Isradipine belongs to the dihydropyridine (DHP) class of calcium channel blockers (CCBs), the most widely used class of CCBs. It is structurally related to felodipine, nifedipine, and nimodipine and is the most potent calcium-channel blocking agent of the DHP class. Isradipine binds to calcium channels with high affinity and specificity and inhibits calcium flux into cardiac and arterial smooth muscle cells. It exhibits greater selectivity towards arterial smooth muscle cells owing to alternative splicing of the alpha-1 subunit of the channel and increased prevalence of inactive channels in smooth muscle cells. Isradipine may be used to treat mild to moderate essential hypertension.
Jasmonic acid is found in apple. Esters are present in Jasminum grandiflorum (royal jasmine) and are responsible for its odour. Jasmonic acid is a member of the jasmonate class of plant hormones. It is biosynthesized from linolenic acid by the octadecanoid pathway
Kaempferol, also known as rhamnolutein or c.i. 75640, belongs to the class of organic compounds known as flavonols. Flavonols are compounds that contain a flavone (2-phenyl-1-benzopyran-4-one) backbone carrying a hydroxyl group at the 3-position. Thus, kaempferol is considered to be a flavonoid molecule. A tetrahydroxyflavone in which the four hydroxy groups are located at positions 3, 5, 7 and 4'. Kaempferol is a very hydrophobic molecule, practically insoluble in water, and relatively neutral. Kaempferol exists in all eukaryotes, ranging from yeast to humans. Kaempferol is a bitter tasting compound. Kaempferol is found, on average, in the highest concentration within a few different foods, such as saffrons, capers, and cumins and in a lower concentration in lovages, endives, and cloves. Kaempferol has also been detected, but not quantified, in several different foods, such as shallots, pine nuts, feijoa, kombus, and chicory leaves. This could make kaempferol a potential biomarker for the consumption of these foods. Kaempferol is a potentially toxic compound.
Ketoleucine is an abnormal metabolite that arises from the incomplete breakdown of branched-chain amino acids. Ketoleucine is both a neurotoxin and a metabotoxin. A neurotoxin causes damage to nerve cells and nerve tissues. A metabotoxin is an endogenously produced metabolite that causes adverse health effects at chronically high levels. Chronically high levels of ketoleucine are associated with maple syrup urine disease (MSUD). MSUD is a metabolic disorder caused by a deficiency of the branched-chain alpha-keto acid dehydrogenase complex (BCKDC), leading to a buildup of the branched-chain amino acids (leucine, isoleucine, and valine) and their toxic by-products (ketoacids) in the blood and urine. The symptoms of MSUD often show in infancy and lead to severe brain damage if untreated. MSUD may also present later depending on the severity of the disease. If left untreated in older individuals, during times of metabolic crisis, symptoms of the condition include uncharacteristically inappropriate, extreme, or erratic behaviour and moods, hallucinations, anorexia, weight loss, anemia, diarrhea, vomiting, dehydration, lethargy, oscillating hypertonia and hypotonia, ataxia, seizures, hypoglycemia, ketoacidosis, opisthotonus, pancreatitis, rapid neurological decline, and coma.  In maple syrup urine disease, the brain concentration of branched-chain ketoacids can increase 10- to 20-fold. This leads to a depletion of glutamate and a consequent reduction in the concentration of brain glutamine, aspartate, alanine, and other amino acids. The result is a compromise of energy metabolism because of a failure of the malate-aspartate shuttle and a diminished rate of protein synthesis (PMID: 15930465).
Kynurenine is a metabolite of the amino acid tryptophan used in the production of niacin. L-Kynurenine is a central compound of the tryptophan metabolism pathway since it can change into the neuroprotective agent kynurenic acid or to the neurotoxic agent quinolinic acid. The break-up of these endogenous compounds' balance can be observable in many disorders such as stroke, epilepsy, multiple sclerosis, and amyotrophic lateral sclerosis. It can also occur in neurodegenerative disorders such as Parkinson's disease, Huntington's, and Alzheimer's disease; and in mental disorders such as schizophrenia and depression.
Lactitol is found in herbs and spices. Artificial sweetener used in foods. Sweetness 0.4 x sucrose.Lactitol is a sugar alcohol used as a replacement bulk sweetener for low calorie foods with approximately 40% of the sweetness of sugar. Lactitol is produced by two manufacturers, Danisco and Purac Biochem
Lamivudine is only found in individuals that have used or taken this drug. It is a reverse transcriptase inhibitor and zalcitabine analog in which a sulfur atom replaces the 3&#39; carbon of the pentose ring. It is used to treat Human Immunodeficiency Virus Type 1 (HIV-1) and hepatitis B (HBV).Lamivudine is a synthetic nucleoside analogue and is phosphorylated intracellularly to its active 5'-triphosphate metabolite, lamivudine triphosphate (L-TP). This nucleoside analogue is incorporated into viral DNA by HIV reverse transcriptase and HBV polymerase, resulting in DNA chain termination.
Lamotrigine is an anticonvulsant drug used in the treatment of epilepsy and bipolar disorder. For epilepsy it is used to treat partial seizures, primary and secondary tonic-clonic seizures, and seizures associated with Lennox-Gastaut syndrome. Lamotrigine also acts as a mood stabilizer. It is the first medication since lithium granted Food and Drug Administration (FDA) approval for the maintenance treatment of bipolar type I. Chemically unrelated to other anticonvulsants, lamotrigine has relatively few side-effects and does not require blood monitoring. The exact way lamotrigine works is unknown. [Wikipedia]
Laricitrin, also known as 3'-O-methylmyricetin or 3,4',5,5',7-pentahydroxy-3'-methoxyflavone, belongs to the class of organic compounds known as flavonols. Flavonols are compounds that contain a flavone (2-phenyl-1-benzopyran-4-one) backbone carrying a hydroxyl group at the 3-position. Thus, laricitrin is considered to be a flavonoid lipid molecule. Laricitrin is a very hydrophobic molecule, practically insoluble (in water), and relatively neutral. BioTransformer predicts that laricitrin is a product of isorhamnetin metabolism via a hydroxylation-of-benzene-ortho-to-edg reaction catalyzed by the CYP1A2, CYP2C8, CYP2C9, and CYP3A4 enzymes (PMID: 30612223).
Dodecanoic acid, also known as dodecanoate or lauric acid, belongs to the class of organic compounds known as medium-chain fatty acids. These are fatty acids with an aliphatic tail that contains between 4 and 12 carbon atoms. Dodecanoic acid is a very hydrophobic molecule, practically insoluble (in water), and relatively neutral. Dodecanoic acid is the main fatty acid in coconut oil and in palm kernel oil, and is believed to have antimicrobial properties. It is a white, powdery solid with a faint odour of bay oil. Dodecanoic acid, although slightly irritating to mucous membranes, has a very low toxicity and so is used in many soaps and shampoos.
Letrozole (INN, trade name Femara) is an oral non-steroidal aromatase inhibitor that has been introduced for the adjuvant treatment of hormonally-responsive breast cancer
Levocetirizine is a second-generation piperazine H1-antihistamine. It has also been labeled as a third-generation antihistamine because it is developed from a second-generation antihistamine (cetirizine).
Linezolid is only found in individuals that have used or taken this drug. It is a synthetic antibiotic, the first of the oxazolidinone class, used for the treatment of infections caused by multi-resistant bacteria including streptococcus and methicillin-resistant Staphylococcus aureus (MRSA). Linezolid is a synthetic antibacterial agent of the oxazolidinone class of antibiotics. It has in vitro activity against aerobic Gram positive bacteria, certain Gram negative bacteria and anaerobic microorganisms. It selectively inhibits bacterial protein synthesis through binding to sites on the bacterial ribosome and prevents the formation of a functional 70S-initiation complex. Specifically, linezolid binds to a site on the bacterial 23S ribosomal RNA of the 50S subunit and prevents the formation of a functional 70S initiation complex, which is an essential component of the bacterial translation process. The results of time-kill studies have shown linezolid to be bacteriostatic against enterococci and staphylococci. For streptococci, linezolid was found to be bactericidal for the majority of strains. Linezolid is also a reversible, nonselective inhibitor of monoamine oxidase. Therefore, linezolid has the potential for interaction with adrenergic and serotonergic agents.
Linoleic acid is a doubly unsaturated fatty acid, also known as an omega-6 fatty acid, occurring widely in plant glycosides. In this particular polyunsaturated fatty acid (PUFA), the first double bond is located between the sixth and seventh carbon atom from the methyl end of the fatty acid (n-6). Linoleic acid is an essential fatty acid in human nutrition because it cannot be synthesized by humans. It is used in the biosynthesis of prostaglandins (via arachidonic acid) and cell membranes (From Stedman, 26th ed). Linoleic acid is found to be associated with isovaleric acidemia, which is an inborn error of metabolism.
Liquiritigenin is found in alfalfa. Liquiritigenin is isolated from Glycyrrhiza, Medicago, Myroxylon, Cicer, and all Leguminosae species. Several glycosides, particularly rutinoside and neohesperidoside, are important in influencing citrus fruit flavour.
Lorazepam is only found in individuals that have used or taken this drug. It is a benzodiazepine used as an anti-anxiety agent with few side effects. It also has hypnotic, anticonvulsant, and considerable sedative properties and has been proposed as a preanesthetic agent. [PubChem]Lorazepam binds to an allosteric site on GABA-A receptors, which are pentameric ionotropic receptors in the CNS. Binding potentiates the effects of the inhibitory neurotransmitter GABA, which upon binding opens the chloride channel in the receptor, allowing chloride influx and causing hyperpolerization of the neuron.
Losartan is an angiotensin-receptor blocker (ARB) that may be used alone or with other agents to treat hypertension. Losartan and its longer acting metabolite, E-3174, lower blood pressure by antagonizing the renin-angiotensin-aldosterone system (RAAS); they compete with angiotensin II for binding to the type-1 angiotensin II receptor (AT1) subtype and prevents the blood pressure increasing effects of angiotensin II. Unlike angiotensin-converting enzyme (ACE) inhibitors, ARBs do not have the adverse effect of dry cough. Losartan may be used to treat hypertension, isolated systolic hypertension, left ventricular hypertrophy and diabetic nephropathy. It may also be used as an alternative agent for the treatment of systolic dysfunction, myocardial infarction, coronary artery disease, and heart failure.
As most NSAIDs, loxoprofen is a non-selective cyclooxygenase inhibitor, and works by reducing the synthesis of prostaglandins from arachidonic acid. Loxoprofen (INN) is a non-steroidal anti-inflammatory drug in the propionic acid derivatives group, which also includes ibuprofen and naproxen among others. It is marketed in Brazil, Mexico and Japan by Sankyo as its sodium salt, loxoprofen sodium, under the trade name Loxonin, Argentina as Oxeno and in India as Loxomac. It is available in these countries for oral administration, and a transdermal preparation was approved for sale in Japan on January 2006. Loxoprofen is a prodrug. It is quickly converted to its active trans-alcohol metabolite following oral administration, and reaches its peak plasma concentration within 30 to 50 minutes.
m-Coumaric acid, also known as 3-coumarate, belongs to the class of organic compounds known as hydroxycinnamic acids. Hydroxycinnamic acids are compounds containing an cinnamic acid where the benzene ring is hydroxylated. m-Coumaric acid exists in all living organisms, ranging from bacteria to humans. m-Coumaric acid (CAS: 588-30-7) is a polyphenol metabolite from caffeic acid, formed by the gut microflora. Outside of the human body, m-Coumaric acid is found, on average, in the highest concentration within a few different foods, such as olives, corns, and beers. m-Coumaric acid has also been detected, but not quantified in several different foods, such as carrots, strawberries, grape wines, garden tomato, and bilberries. MCT-mediated absorption of phenolic compounds per se and their colonic metabolites would exert a significant impact on human health (PMID:16870009, 15479001, 15479001). m-Coumaric acid is transported by the monocarboxylic acid transporter (MCT). The amount of this compound in human biofluids is diet-dependant. m-Coumaric acid is detected after the consumption of whole grain.
Maleic acid is a dicarboxylic acid, a molecule with two carboxyl groups. It consists of an ethylene group flanked by two carboxylic acid groups. Maleic acid is the cis isomer of butenedioic acid, whereas fumaric acid is the trans isomer. The cis isomer is the less stable one of the two; the difference in heat of combustion is 22.7 kJ/mol. The physical properties of maleic acid are very different from that of fumaric acid. Maleic acid is soluble in water whereas fumaric acid is not and the melting point of maleic acid (130 - 131 oC) is also much lower than that of fumaric acid (287 oC). Maleic acid is converted into maleic anhydride by dehydration, to malic acid by hydration, and to succinic acid by hydrogenation. Maleic acid is used in making polyesters for fibre-reinforced laminated moldings and paint vehicles. More specifically it is used in the manufacture of phthalic-type alkyd and polyester resins, surface coatings, copolymers, plasticizers, lubricant additives and agricultural chemicals. It is also found in adhesives and sealants and as a preservative for oils and fats. In the natural world, maleic acid has been identified in ginseng, pineapple, cacao plants, sour cherries and corn. A large number of microbes are able to convert maleic acid to D-malate using the enzyme maleate hydratase (PMID: 1444397).
It is an isomer of cresotinic acid (2-hydroxy-3-methylbenzoic acid) and oxymethylbenzoic acid (2-methoxybenzoic acid). Derivatives of mandelic acid are formed as a result of metabolism of adrenaline and noradrenaline by monoamine oxidase and catechol-o-methyl transferase. It is also present in certain skin care products, is an intermediate molecule in the production of other biochemicals, may be used as an analytical reagent and is a precursor in the manufacture of dyes. Mandelic acid is an aromatic alpha hydroxy acid with the molecular formula C8H8O3. It is a white crystalline solid that is soluble in water and most common organic solvents. Mandelic acid is found to be associated with phenylketonuria, which is an inborn error of metabolism.
Mannitol, or hexan-1,2,3,4,5,6-hexol (C6H8(OH)6), is an alcohol and a sugar (sugar alcohol), or a polyol, it is a stereoisomer of sorbitol and is similar to the C5 xylitol. The structure of mannitol is made of a straight chain of six carbon atoms, each of which is substituted with a hydroxyl group. Mannitol is one of the most abundant energy and carbon storage molecules in nature, it is produced by a wide range of organisms such as bacteria, fungi and plants (PMID: 19578847). In medicine, mannitol is used as a diuretic and renal diagnostic aid. Mannitol has little significant energy value as it is largely eliminated from the body before any metabolism can take place. It can be used to treat oliguria associated with kidney failure or other manifestations of inadequate renal function and has been used for determination of glomerular filtration rate. Mannitol is also commonly used as a research tool in cell biological studies, usually to control osmolarity. Mannitol has a tendency to lose a hydrogen ion in aqueous solutions, which causes the solution to become acidic. For this, it is not uncommon to add a weak base, such as sodium bicarbonate, to the solution to adjust its pH. Mannitol is a non-permeating molecule i.e., it cannot cross biological membranes. Mannitol is an osmotic diuretic agent and a weak renal vasodilator. Mannitol is found to be associated with cytochrome c oxidase deficiency and ribose-5-phosphate isomerase deficiency, which are inborn errors of metabolism. Mannitol is also a microbial metabolite found in Aspergillus, Candida, Clostridium, Gluconobacter, Lactobacillus, Lactococcus, Leuconostoc, Pseudomonas, Rhodobacteraceae, Saccharomyces, Streptococcus, Torulaspora and Zymomonas (PMID: 15240312; PMID: 29480337).
Melatonin is a biogenic amine that is found in animals, plants and microbes. Aaron B. Lerner of Yale University is credited for naming the hormone and for defining its chemical structure in 1958. In mammals, melatonin is produced by the pineal gland. The pineal gland is small endocrine gland, about the size of a rice grain and shaped like a pine cone (hence the name), that is located in the center of the brain (rostro-dorsal to the superior colliculus) but outside the blood-brain barrier. The secretion of melatonin increases in darkness and decreases during exposure to light, thereby regulating the circadian rhythms of several biological functions, including the sleep-wake cycle. In particular, melatonin regulates the sleep-wake cycle by chemically causing drowsiness and. lowering the body temperature. Melatonin is also implicated in the regulation of mood,learning and memory, immune activity, dreaming, fertility and reproduction. Melatonin is also an effective antioxidant. Most of the actions of melatonin are mediated through the binding and activation of melatonin receptors. Individuals with autism spectrum disorders(ASD) may have lower than normal levels of melatonin. A 2008 study found that unaffected parents of individuals with ASD also have lower melatonin levels, and that the deficits. were associated with low activity of the ASMT gene, which encodes the last enzyme of melatonin synthesis. Reduced melatonin production has also been proposed as a likely factor in the significantly higher cancer rates in night workers.
Melezitose, also spelled melicitose, is a nonreducing trisaccharide sugar that is produced by many plant sap eating insects, including aphids such as Cinara pilicornis by an enzyme reaction. This is beneficial to the insects, as it reduces the stress of osmosis by reducing their own water potential. The melezitose is part of the honeydew which acts as an attractant for ants and also as a food for bees. This is useful to the lice as they have a symbiotic relationship with ants. Melezitose can be partially hydrolyzed to glucose and turanose the latter of which is an isomer of sucrose (Wikipedia).
Methionine sulfoxide belongs to the class of organic compounds known as l-alpha-amino acids. These are alpha amino acids which have the L-configuration of the alpha-carbon atom. Methionine sulfoxide exists in all living species, ranging from bacteria to humans. Within humans, methionine sulfoxide participates in a number of enzymatic reactions. In particular, methionine sulfoxide can be biosynthesized from L-methionine through its interaction with the enzyme methionine-R-sulfoxide reductase B3. In addition, methionine sulfoxide can be biosynthesized from L-methionine through the action of the enzyme methionine-R-sulfoxide reductase b2, mitochondrial. In humans, methionine sulfoxide is involved in the metabolic disorder called hypermethioninemia.
Methotrexate is only found in individuals that have used or taken this drug. It is an antineoplastic antimetabolite with immunosuppressant properties. It is an inhibitor of tetrahydrofolate dehydrogenase and prevents the formation of tetrahydrofolate, necessary for synthesis of thymidylate, an essential component of DNA. [PubChem]Methotrexate anti-tumor activity is a result of the inhibition of folic acid reductase, leading to inhibition of DNA synthesis and inhibition of cellular replication. The mechanism involved in its activity against rheumatoid arthritis is not known.
Methyl vanillate is a member of the class of compounds known as m-methoxybenzoic acids and derivatives. These compounds are benzoic acids in which the hydrogen atom at position 3 of the benzene ring is replaced by a methoxy group. Methyl vanillate is considered to be a slightly soluble in water acidic compound. Methyl vanillate can be synthesized from vanillic acid. Vanillic acid is a phenolic acid or chlorogenic acid that is an oxidized form of vanillin. Vanillic acid is also an intermediate in the production of vanillin from ferulic acid. It is found in some forms of vanilla and many other plant extracts. It is a flavouring and scent agent that produces a pleasant, creamy odour. Vanillic acid is also found in wine and vinegar. Vanillic acid is a metabolic by-product of caffeic acid and is often found in the urine of humans who have consumed coffee, chocolate, tea, and vanilla-flavoured confectionary. Vanillic acid selectively and specifically inhibits 5'-nucleotidase activity (PMID:16899266 ). Vanillic acid is also a microbial metabolite found in several bacterial genera including Amycolatopsis, Delftia, and Pseudomonas (PMID:11152072 , 10543794 , 11728709 , 9579070 ). Methyl vanillate has been identified in foods such as cow's milk (PMID:4682334) and beer (PMID:20800742).
Milrinone is only found in individuals that have used or taken this drug. It is a positive inotropic cardiotonic agent with vasodilator properties. Milrinone inhibits erythrocyte phosphodiesterase, resulting in an increase in erythrocyte cAMP activity. Subsequently, the erythrocyte membrane becomes more resistant to deformity. Along with erythrocyte activity, Milrinone also decreases blood viscosity by reducing plasma fibrinogen concentrations and increasing fibrinolytic activity. It also inhibits cAMP phosphodiesterase activity in myocardium and vascular smooth muscle. Milrinone is a derivative of amrinone and has 20-30 times the ionotropic potency of amrinone. [PubChem]
allo-Inositol is an inositol isoform. Inositol is a derivative of cyclohexane with six hydroxyl groups, making it a polyol. It also is known as a sugar alcohol, having exactly the same molecular formula as glucose or other hexoses. Inositol exists in nine possible stereoisomers, including scyllo-inositol, myo-inositol (the most abundant), muco-inositol, D-chiro-inositol, L-chiro-inositol, neo-inositol, allo-inositol, epi-inositol, and cis-inositol.
Myricetin, also known as cannabiscetin or myricetol, belongs to the class of organic compounds known as flavonols. Flavonols are compounds that contain a flavone (2-phenyl-1-benzopyran-4-one) backbone carrying a hydroxyl group at the 3-position. Thus, myricetin is considered to be a flavonoid lipid molecule. A hexahydroxyflavone that is flavone substituted by hydroxy groups at positions 3, 3', 4', 5, 5' and 7. Myricetin is a very hydrophobic molecule, practically insoluble in water, and relatively neutral. Myricetin is found, on average, in the highest concentration within a few different foods, such as common walnuts, carobs, and fennels and in a lower concentration in welsh onions, yellow bell peppers, and jutes. Myricetin has also been detected, but not quantified in several different foods, such as napa cabbages, sesames, mixed nuts, lichee, and garden cress.
Asymmetric dimethylarginine (ADMA) is a naturally occurring chemical found in blood plasma. It is a metabolic by-product of continual protein modification processes in the cytoplasm of all human cells. It is closely related to L-arginine, a conditionally-essential amino acid. ADMA interferes with L-arginine in the production of nitric oxide, a key chemical to endothelial and hence cardiovascular health. Asymmetric dimethylarginine is created in protein methylation, a common mechanism of post-translational protein modification. This reaction is catalyzed by an enzyme set called S-adenosylmethionine protein N-methyltransferases (protein methylases I and II). The methyl groups transferred to create ADMA are derived from the methyl group donor S-adenosylmethionine, an intermediate in the metabolism of homocysteine. (Homocysteine is an important blood chemical, because it is also a marker of cardiovascular disease). After synthesis, ADMA migrates into the extracellular space and thence into blood plasma. Asymmetric dimethylarginine is measured using high performance liquid chromatography. ADMA has been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID: 22626821).
2-Furoylglycine is an acyl glycine. Acyl glycines are normally minor metabolites of fatty acids. However, the excretion of certain acyl glycines is increased in several inborn errors of metabolism. In certain cases the measurement of these metabolites in body fluids can be used to diagnose disorders associated with mitochondrial fatty acid beta-oxidation. Acyl glycines are produced through the action of glycine N-acyltransferase (EC 2.3.1.13) which is an enzyme that catalyzes the chemical reaction:. acyl-CoA + glycine < -- > CoA + N-acylglycine. Dietary studies show that 2-Furoylglycine precursors are of exogenous origin. Most probably from furan derivatives found in food prepared by strong heating. This may explain the absence of 2-furoylglycine in urine of breastfed children (PMID 4630229). 2-Furoylglycine is also a microbial metabolite.
N-Acetylaspartylglutamate (NAAG) is a neuropeptide found in millimolar concentrations in the brain that is localized to subpopulations of glutamatergic, cholinergic, GABAergic, and noradrenergic neuronal systems. NAAG is released upon depolarization by a Ca(2+)-dependent process and is an agonist at mGluR3 receptors and an antagonist at NMDA receptors. NAAG is catabolized to N-acetylaspartate and glutamate primarily by glutamate carboxypeptidase II, which is expressed on the extracellular surface of astrocytes. The levels of NAAG and the activity of carboxypeptidase II are altered in a regionally specific fashion in several neuropsychiatric disorders (PMID:9361299). N-Acetylaspartylglutamic acid (NAAG) is a purported precursor of N-acetylaspartic acid (NAA) and is present at about one-tenth of the concentration of NAA in the brain. NAAG has been reported to activate N-methyl-D-aspartic acid (NMDA) receptors in neurons. Previous immunohistochemical studies in the vertebrate central nervous system (CNS) have suggested that NAAG is exclusively localized to neurons. Recent evidence, however, indicates that NAAG might also be localized to nonneuronal cells within the CNS. Only traces of NAA and NAAG are detectable in other tissues. Some compounds can change levels of NAA and NAAG in the brain. For example, methylphenidate increases the levels of NAA and NAAG in the cerebral cortex; amphetamine also increases NAA concentration in a mature brain by 26%, raising the possibility that other neurochemical systems might be involved in the clinical effects of stimulants (PMID:10603234).
N4-Acetylcytidine is a modified nucleoside. N4-acetylcytidine is an endogenous urinary nucleoside product of the degradation of transfer ribonucleic acid (tRNA); urinary nucleosides are biological markers for patients with colorectal cancer. tRNA has been shown to be excreted in abnormal amounts in the urine of cancer patients. tRNA from neoplastic tissue had a much more rapid turnover rate than the tRNA from the corresponding normal tissue. Evidence indicates that methylation of tRNA occurs only after synthesis of the intact macromolecule. Because there are no specific enzyme systems to incorporate the modified nucleosides into the macromolecular nucleic acid, these nucleosides once released in the process of tRNA turnover cannot be reutilized, nor are they further degraded, but are excreted in urine. (PMID: 15991285, 3506820).
N-Acetyl-D-Glucosamine (N-acetlyglucosamine) is a monosaccharide derivative of glucose. Chemically it is an amide between glucosamine and acetic acid. A single N-acetlyglucosamine moiety linked to serine or threonine residues on nuclear and cytoplasmic proteins -O-GlcNAc, is an ubiquitous post-translational protein modification. O-GlcNAc modified proteins are involved in sensing the nutrient status of the surrounding cellular environment and adjusting the activity of cellular proteins accordingly. O-GlcNAc regulates cellular responses to hormones such as insulin, initiates a protective response to stress, modulates a cell's capacity to grow and divide, and regulates gene transcription. In humans, it exists in skin, cartilage and blood vessel as a component of hyaluronic acid, and bone tissue, cornea and aorta as a component of keratan sulfate. (PMID 16237703).
Cinnamoylglycine is known as a urinary metabolite in man (PMID 649712) although whether it is formed de novo from plant cinnamate or is a plant product excreted. unchanged has not been conclusively demonstrated. When cinnamoylglycine occurs naturally it is probably a food constituent excreted unchanged. It is not found when small quantities (0.5-6 g) of cinnamic acid are fed to man, but by analogy with animal experiments may be produced when much larger quantities are given. (PMID 6743769).
N-formyl-L-methionine is a L-methionine derivative in which one of the hydrogens attached to the nitrogen is replaced by a formyl group. It has a role as a metabolite. It is a proteinogenic amino acid, a N-formyl amino acid and a L-methionine derivative. It is a conjugate acid of a N-formyl-L-methioninate. N-Formyl-L-methionine belongs to the class of organic compounds known as methionine and derivatives. Methionine and derivatives are compounds containing methionine or a derivative thereof resulting from reaction of methionine at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom. N-Formyl-L-methionine is effective in the initiation of protein synthesis. The initiating methionine residue enters the ribosome as N-formylmethionyl-tRNA. This process occurs in Escherichia coli and other bacteria as well as in the mitochondria of eukaryotic cells.
Acetyl-N-formyl-5-methoxykynurenamine (AFMK) results from the oxidative cleavage of the pyrrole ring during melatonin oxidation by myeloperoxidase (MPO), a superoxide anion (O)-dependent reaction. AFMK is also expected to be formed from oxidation catalyzed by the unspecific enzyme indoleamine-2,3-dioxygenase (IDO), found in a variety of cell types including monocyte/macrophage lineages. MPO- and IDO-catalyzed melatonin oxidation has the requirement of O in common, a species formed in large amounts in inflammatory conditions. The non-enzymatic formation of AFMK can also be expected by its direct reaction with highly reactive oxygen species, such as hydroxyl radical and singlet oxygen. Thus, we assume that AFMK is a product formed in a route of melatonin metabolism, especially active in inflammation. As AFMK is biologically more active on leukocytes than melatonin, the metabolizing of melatonin to AFMK at inflammatory sites possibly plays a role in immunomodulation. AFMK is found in the CSF of patients with meningitis, and in some samples at a remarkably high concentration. AFMK was also found in some patients to exceed the concentration of melatonin normally found in serum (PMID: 16150112).
Isobutyrylglycine is an acyl glycine. Acyl glycines are normally minor metabolites of fatty acids. However, the excretion of certain acyl glycines is increased in several inborn errors of metabolism. In certain cases the measurement of these metabolites in body fluids can be used to diagnose disorders associated with mitochondrial fatty acid beta-oxidation. Acyl glycines are produced through the action of glycine N-acyltransferase (EC 2.3.1.13) which is an enzyme that catalyzes the chemical reaction: acyl-CoA + glycine < -- > CoA + N-acylglycine. Isobutyrylglycine is identified in large amount in urine of patients with isobutyryl-CoA dehydrogenase deficiency. Isobutyryl-CoA dehydrogenase deficiency is a disorder caused by the deficiency of isobutyryl-CoA dehydrogenase that is involved in the catabolism of the branched-chain amino acid valine (PMID 15505379). Moreover, Isobutyrylglycine is found to be associated with ethylmalonic encephalopathy and propionic acidemia, which are also inborn errors of metabolism. Isobutyrylglycine is a biomarker for the consumption of cheese.
Isovalerylglycine (IVG) is an acyl glycine. Acyl glycines are normally minor metabolites of fatty acids. However, the excretion of certain acyl glycines is increased in several inborn errors of metabolism. In certain cases the measurement of these metabolites in body fluids can be used to diagnose disorders associated with mitochondrial fatty acid beta-oxidation. Acyl glycines are produced through the action of glycine N-acyltransferase (EC 2.3.1.13) which is an enzyme that catalyzes the chemical reaction: acyl-CoA + glycine < -- > CoA + N-acylglycine. Isovalerylglycine is a byproduct of the catabolism of the aminoacid leucine. Accumulation of isovalerylglycine occurs in Isovaleric Acidemia (IVA). IVA (OMIM/ McKusick 243500) is an autosomal recessive disorder caused by mutations in the isovaleryl-CoA dehydrogenase (EC 1.3.99.10) gene. The deficiency of this enzyme in the metabolism of leucine leads to the accumulation of a series of isovaleryl-CoA metabolites, such as isovalerylglycine. It is very important to caution for false positive results when screening for isovaleric acidemia by tandem mass spectrometry based on dried blood-spot levels of C5-acylcarnitines, including isovalerylcarnitine and its isomer, pivaloylcarnitine; pivaloylcarnitine is derived from pivalate-generating antibiotics, and has caused many false-positive results (PMID: 17850781). Isovalerylglycine is a biomarker for the consumption of cheese.
2-(Methylamino)benzoic acid is found in citrus. 2-(Methylamino)benzoic acid is isolated from grapefruit peel oi
N-Acetylhistamine is a 4-(beta-Acetylaminoethyl)imidazole that is an intermediate in Histidine metabolism. It is generated from Histamine via the enzyme Transferases (EC 2.3.1.-). Histamine is an amine derived by enzymatic decarboxylation of histidine. It is a powerful stimulant of gastric secretion, a constrictor of bronchial smooth muscle, a vasodilator, and also a centrally acting neurotransmitter.
N2,N2-Dimethylguanosine is an urinary nucleoside, a primary degradation product of tRNA. The mean levels of urinary N2,N2-Dimethylguanosine in the patients with colorectal cancer are significantly higher than those in patients with intestinal villous adenoma or the healthy adults (PMID 15991285). N2,N2-Dimethylguanosine has been identified in the human placenta (PMID: 32033212).
Riboprine, also known as isopentenyladenosine or ipa, is a member of the class of compounds known as purine nucleosides. Purine nucleosides are compounds comprising a purine base attached to a ribosyl or deoxyribosyl moiety. Riboprine is slightly soluble (in water) and a very weakly acidic compound (based on its pKa). Riboprine can be found in a number of food items such as peppermint, chinese mustard, custard apple, and green bean, which makes riboprine a potential biomarker for the consumption of these food products.
Naproxen (INN) is a non-steroidal anti-inflammatory drug (NSAID) commonly used for the reduction of mild to moderate pain, fever, inflammation and stiffness caused by conditions such as osteoarthritis, rheumatoid arthritis, psoriatic arthritis, gout, ankylosing spondylitis, injury (like fractures), menstrual cramps, tendonitis, bursitis, and the treatment of primary dysmenorrhea. Naproxen and naproxen sodium are marketed under various trade names including: Aleve, Anaprox, Naprogesic, Naprosyn, Naprelan; Naproxen is a non-steroidal anti-inflammatory drug (NSAID) commonly used for the reduction of mild to moderate pain, fever, inflammation and stiffness caused by conditions such as osteoarthritis, rheumatoid arthritis, psoriatic arthritis, gout, ankylosing spondylitis, injury (like fractures), menstrual cramps, tendonitis, bursitis, and the treatment of primary dysmenorrhea. Naproxen and naproxen sodium are marketed under various trade names including: Aleve, Anaprox, Naprogesic, Naprosyn, Naprelan. Naproxen was first marketed as the prescription drug Naprosyn in 1976 and naproxen sodium was first marketed under the trade name Anaprox in 1980. It remains a prescription-only drug in much of the world. The U.S. Food and Drug Administration (FDA) approved the use of naproxen sodium as an over-the-counter (OTC) drug in 1991, where OTC preparations are sold under the trade name Aleve. In Australia, small packets of lower-strength preparations of naproxen sodium are Schedule 2 Pharmacy Medicines; Naproxen is a member of the 2-arylpropionic acid (profen) family of NSAIDs. It is an odorless, white to off-white crystalline substance. It is lipid-soluble, practically insoluble in water with a low pH (below pH 4), while freely soluble in water at 6 pH and above. Naproxen has a melting point of 153 degree centigrade.
Naringin, also known as naringoside or naringin hydrate, is a flavanone-7-O-glycoside between the flavanone naringenin and the disaccharide neohesperidose. Naringin belongs to the flavonoid family. Flavonoids consist of 15 carbon atoms in 3 rings, 2 of which must be benzene rings connected by a 3 carbon chain.  Naringin contains the basic flavonoid structure along with one rhamnose and one glucose unit attached to its aglycone portion, called naringenin, at the 7-carbon position. The steric hindrance provided by the two sugar units makes naringin less potent than its aglycone counterpart, naringenin. Naringin is a bitter tasting compound. Naringin is found, on average, in the highest concentration within a few different foods, such as rosemaries, grapefruit/pummelo hybrids, and grapefruits and in a lower concentration in grape wines, pummelo, and beers. Naringin has also been detected, but not quantified in several different foods, such as citrus, limes, herbs and spices, common oregano, and mandarin orange (clementine, tangerine). Both naringin and hesperetin, which are the aglycones of naringin and hesperidin, occur naturally in citrus fruits. Naringin is the major flavonoid glycoside in grapefruit and gives grapefruit juice its bitter taste. Narinigin exerts a variety of pharmacological effects such as antioxidant activity, blood lipid-lowering, anticarcinogenic activity, and inhibition of selected cytochrome P450 enzymes including CYP3A4 and CYP1A2, which may result in several drug interactions in-vitro.
Nelfinavir is only found in individuals that have used or taken this drug. It is a potent HIV-1 protease inhibitor. It is used in combination with other antiviral drugs in the treatment of HIV in both adults and children. [PubChem]Nelfinavir inhibits the HIV viral proteinase enzyme which prevents cleavage of the gag-pol polyprotein, resulting in noninfectious, immature viral particles.
Nervonic acid is a long chain unsaturated fatty acid that is enriched in sphingomyelin. It consists of choline, sphingosine, phosphoric acid, and fatty acid. Nervonic acid may enhance the brain functions and prevent demyelination (Chemical Land21). Research shows that there is negative relationship between nervonic acid and obesity-related risk factors (PMID:16394593). Demyelination in adrenoleukodystrophy (ALD) is associated with an accumulation of very long chain saturated fatty acids stemming from a genetic defect in the peroxisomal beta oxidation system responsible for the chain shortening of these fatty acids. Sphingolipids from post mortem ALD brain have decreased levels of nervonic acid, 24:1(n-9), and increased levels of stearic acid, 18:0. (PMID:8072429).
Nicotinic acid, also known as niacin or vitamin B3, is a water-soluble vitamin whose derivatives such as NADH, NAD, NAD+, and NADP play essential roles in energy metabolism in the living cell and DNA repair. The designation vitamin B3 also includes the amide form, nicotinamide or niacinamide. Severe lack of niacin causes the deficiency disease pellagra, whereas a mild deficiency slows down the metabolism decreasing cold tolerance. The recommended daily allowance of niacin is 2-12 mg a day for children, 14 mg a day for women, 16 mg a day for men, and 18 mg a day for pregnant or breast-feeding women. It is found in various animal and plant tissues and has pellagra-curative, vasodilating, and antilipemic properties. The liver can synthesize niacin from the essential amino acid tryptophan, but the synthesis is extremely slow and requires vitamin B6; 60 mg of tryptophan are required to make one milligram of niacin. Bacteria in the gut may also perform the conversion but are inefficient.
Nicotinuric acid is an acylglycine. Acylglycines are normally minor metabolites of fatty acids. However, the excretion of certain acylglycines is increased in several inborn errors of metabolism. In certain cases, the measurement of these metabolites in body fluids can be used to diagnose disorders associated with mitochondrial fatty acid beta-oxidation. Acylglycines are produced through the action of glycine N-acyltransferase (EC 2.3.1.13) which is an enzyme that catalyzes the chemical reaction acyl-CoA + glycine <-> CoA + N-acylglycine. Nicotinuric acid is the major detoxification product of nicotinic acid. It may serve as a simple quantitative index of hepatic biotransformation of nicotinic acid (PMID:3243933).
Nimodipine is a 1,4-dihydropyridine calcium channel blocker. It acts primarily on vascular smooth muscle cells by stabilizing voltage-gated L-type calcium channels in their inactive conformation. By inhibiting the influx of calcium in smooth muscle cells, nimodipine prevents calcium-dependent smooth muscle contraction and subsequent vasoconstriction. Compared to other calcium channel blocking agents, nimodipine exhibits greater effects on cerebral circulation than on peripheral circulation. Nimodipine is used to as an adjunct to improve the neurologic outcome following subarachnoid hemorrhage from ruptured intracranial aneurysm.
Nitazoxanide, also known by the brand name Alinia, is a synthetic nitrothiazolyl-salicylamide derivative and an anti-protozoal agent. It is approved for treatment of infectious diarrhea caused by Cryptosporidium parvum and Giardia lamblia in patients 1 year of age and older. Following oral administration it is rapidly hydrolyzed to its active metabolite, tizoxanide, which is 99% protein bound. Peak concentrations are observed 1-4 hours after administration. It is excreted in the urine, bile and feces. Untoward effects include abdominal pain, vomiting and diarrhea. [Wikipedia]
Nitrazepam is only found in individuals that have used or taken this drug. It is a benzodiazepine derivative used as an anticonvulsant and hypnotic.Nitrazepam belongs to a group of medicines called benzodiazepines. It acts on benzodiazepine receptors in the brain which are associated with the GABA receptors causing an enhanced binding of GABA (gamma amino butyric acid) to GABAA receptors. GABA is a major inhibitory neurotransmitter in the brain, involved in inducing sleepiness, muscular relaxation and control of anxiety and fits, and slows down the central nervous system. The anticonvulsant properties of nitrazepam and other benzodiazepines may be in part or entirely due to binding to voltage-dependent sodium channels rather than benzodiazepine receptors. Sustained repetitive firing seems to be limited by benzodiazepines effect of slowing recovery of sodium channels from inactivation.
Nitrendipine is only found in individuals that have used or taken this drug. It is a calcium channel blocker with marked vasodilator action. It is an effective antihypertensive agent and differs from other calcium channel blockers in that it does not reduce glomerular filtration rate and is mildly natriuretic, rather than sodium retentive. [PubChem]By deforming the channel, inhibiting ion-control gating mechanisms, and/or interfering with the release of calcium from the sarcoplasmic reticulum, Nitrendipine inhibits the influx of extracellular calcium across the myocardial and vascular smooth muscle cell membranes The decrease in intracellular calcium inhibits the contractile processes of the myocardial smooth muscle cells, causing dilation of the coronary and systemic arteries, increased oxygen delivery to the myocardial tissue, decreased total peripheral resistance, decreased systemic blood pressure, and decreased afterload.
Nizatidine is only found in individuals that have used or taken this drug. It is a histamine H2 receptor antagonist with low toxicity that inhibits gastric acid secretion. The drug is used for the treatment of duodenal ulcers. [PubChem]Nizatidine competes with histamine for binding at the H<sub>2</sub>-receptors on the gastric basolateral membrane of parietal cells. Competitive inhibition results in reduction of basal and nocturnal gastric acid secretions. The drug also decreases the gastric acid response to stimuli such as food, caffeine, insulin, betazole, or pentagastrin.
L-Norleucine, also known as L-aminohexanoate or caprine, belongs to the class of organic compounds known as l-alpha-amino acids. These are alpha amino acids which have the L-configuration of the alpha-carbon atom. Thus, L-norleucine is considered to be a fatty acid lipid molecule. An unnatural amino acid that is used experimentally to study protein structure and function. L-Norleucine is a very hydrophobic molecule, practically insoluble in water, and relatively neutral. L-Norleucine exists in all eukaryotes, ranging from yeast to humans. Outside of the human body, L-Norleucine has been detected, but not quantified in cow milk. This could make L-norleucine a potential biomarker for the consumption of these foods. It binds reversibly to the kringle domain of plasminogen and blocks the binding of plasminogen to fibrin and its activation to plasmin.
O-Acetylserine is an α-amino acid with the chemical formula HO2CCH(NH2)CH2OC(O)CH3. It is an intermediate in the biosynthesis of the common amino acid cysteine in bacteria and plants. O-Acetylserine is biosynthesized by acetylation of the serine by the enzyme serine transacetylase. The enzyme O-acetylserine (thiol)-lyase, using sulfide sources, converts this ester into cysteine, releasing acetate. O-Acetylserine belongs to the class of organic compounds known as l-alpha-amino acids. These are alpha amino acids which have the L-configuration of the alpha-carbon atom. O-Acetylserine (OASS) is an acylated amino acid derivative. O-Acetylserine exists in all living species, ranging from bacteria to humans. Outside of the human body, O-Acetylserine has been detected, but not quantified in several different foods, such as okra, vaccinium (blueberry, cranberry, huckleberry), rapes, sparkleberries, and lingonberries. This could make O-acetylserine a potential biomarker for the consumption of these foods.
Octadecanedioic acid, also known as 1,18-octadecanedioate or octadecane-1,18-dioate, belongs to the class of organic compounds known as long-chain fatty acids. These are fatty acids with an aliphatic tail that contains between 13 and 21 carbon atoms. In the case of octadecanedioic acid, it has carboxyl groups at both ends of the chain, not just one.  Octadecanedioic acid is a very hydrophobic molecule, practically insoluble (in water).  Octadecanedioic acid is a long-chain dicarboxylic acid normally not found in humans that has been identified in the blood serum in Reye's syndrome patients (PMID:¬†3746531).  There may also be an association with colorectal cancer (PMID: 25037050).
Oleic acid (or 9Z)-Octadecenoic acid) is an unsaturated C-18 or an omega-9 fatty acid that is the most widely distributed and abundant fatty acid in nature. It occurs naturally in various animal and vegetable fats and oils. It is an odorless, colorless oil, although commercial samples may be yellowish. The name derives from the Latin word oleum, which means oil. Oleic acid is the most abundant fatty acid in human adipose tissue, and the second most abundant in human tissues overall, following palmitic acid. Oleic acid is a component of the normal human diet, being a part of animal fats and vegetable oils. Triglycerides of oleic acid represent the majority of olive oil (about 70%). Oleic acid triglycerides also make up 59‚Äì75% of pecan oil, 61% of canola oil, 36‚Äì67% of peanut oil, 60% of macadamia oil, 20‚Äì80% of sunflower oil, 15‚Äì20% of grape seed oil, sea buckthorn oil, 40% of sesame oil, and 14% of poppyseed oil. High oleic variants of plant sources such as sunflower (~80%) and canola oil (70%) also have been developed. consumption has been associated with decreased low-density lipoprotein (LDL) cholesterol, and possibly with increased high-density lipoprotein (HDL) cholesterol, however, the ability of oleic acid to raise HDL is still debated. Oleic acid may be responsible for the hypotensive (blood pressure reducing) effects of olive oil that is considered a health benefit. Oleic acid is used in manufacturing of surfactants, soaps, plasticizers. It is also used as an emulsifying agent in foods and pharmaceuticals. Oleic acid is used commercially in the preparation of oleates and lotions, and as a pharmaceutical solvent.
Olmesartan is an antihypertensive agent which belongs to the class of medicines called angiotensin II receptor antagonists. It acts rapidly to lower high blood pressure. It is marketed worldwide by Daiichi Sankyo, Ltd. and in the United States by Daiichi Sankyo, Inc. and Forest Laboratories.
Used to treat allergic conjunctivitis (itching eyes), olopatadine inhibits the release of histamine from mast cells. It is a relatively selective histamine H1 antagonist that inhibits the in vivo and in vitro type 1 immediate hypersensitivity reaction including inhibition of histamine induced effects on human conjunctival epithelial cells.
Omeprazole is a highly effective inhibitor of gastric acid secretion used in the therapy of stomach ulcers, dyspepsia, peptic ulcer disease , gastroesophageal reflux disease and Zollinger-Ellison syndrome. The drug inhibits the H(+)-K(+)-ATPase (H(+)-K(+)-exchanging ATPase) in the proton pump of Gastric Parietal Cells.--Pubchem. Omeprazole is one of the most widely prescribed drugs internationally and is available over the counter in some countries.
Orlistat is a drug designed to treat obesity. Its primary function is preventing the absorption of fats from the human diet, thereby reducing caloric intake. Orlistat works by inhibiting pancreatic lipase, an enzyme that breaks down triglycerides in the intestine. Without this enzyme, triglycerides from the diet are prevented from being hydrolyzed into absorbable free fatty acids and are excreted undigested.
Oxalacetic acid, also known as oxaloacetic acid, keto-oxaloacetate or 2-oxobutanedioate, belongs to the class of organic compounds known as short-chain keto acids and derivatives. These are keto acids with an alkyl chain the contains less than 6 carbon atoms. Oxalacetic acid is a metabolic intermediate in many processes that occur in animals and plants. It takes part in gluconeogenesis, the urea cycle, the glyoxylate cycle, amino acid synthesis, fatty acid synthesis and the citric acid cycle. Oxalacetic acid exists in all living species, ranging from bacteria to plants to humans. Within humans, oxalacetic acid participates in a number of enzymatic reactions. In particular, oxalacetic acid is an intermediate of the citric acid cycle, where it reacts with acetyl-CoA to form citrate, catalyzed by citrate synthase. It is also involved in gluconeogenesis and the urea cycle. In gluconeogenesis oxaloacetate is decarboxylated and phosphorylated by phosphoenolpyruvate carboxykinase and becomes 2-phosphoenolpyruvate using guanosine triphosphate (GTP) as phosphate source. In the urea cycle, malate is acted on by malate dehydrogenase to become oxaloacetate, producing a molecule of NADH. After that, oxaloacetate can be recycled to aspartate, as this recycling maintains the flow of nitrogen into the cell. In mice, injections of oxalacetic acid have been shown to promote brain mitochondrial biogenesis, activate the insulin signaling pathway, reduce neuroinflammation and activate hippocampal neurogenesis (PMID: 25027327). Oxalacetic acid has also been reported to reduce hyperglycemia in type II diabetes and to extend longevity in C. elegans (PMID: 25027327). Outside of the human body, oxalacetic acid has been detected, but not quantified in, several different foods, such as Persian limes, lemon balms, wild rice, canola, and peanuts. This could make oxalacetic acid a potential biomarker for the consumption of these foods.
Oxaprozin is only found in individuals that have used or taken this drug. It is a non-narcotic, non-steroidal anti-inflammatory drug (NSAID), used to relieve the inflammation, swelling, stiffness, and joint pain associated with osteoarthritis and rheumatoid arthritis.Anti-inflammatory effects of Oxaprozin are believed to be due to inhibition of cylooxygenase in platelets which leads to the blockage of prostaglandin synthesis. Antipyretic effects may be due to action on the hypothalamus, resulting in an increased peripheral blood flow, vasodilation, and subsequent heat dissipation. Oxaprozin is a non-selective NSAID, with a cell assay system showing lower COX-2 selectivity implying higher COX-1 selectivity.
Oxazepam is only found in individuals that have used or taken this drug. It is an intermediate-acting benzodiazepine used to treat alcohol withdrawal and anxiety disorders. It is a metabolite of diazepam, prazepam, temazepam, and clorazepate, and has moderate amnesic, anxiolytic, anticonvulsant, hypnotic, sedative, and skeletal muscle relaxant properties compared to other benzodiazepines (Wikipedia). Like other benzodiazepines, oxazepam exerts its anxiolytic effects by potentiating the effect of gamma-aminobutyric acid (GABA) on GABA-A receptors through a cooperative mechanism of action. GABA receptors are ionotropic chloride-linked channel receptors that produce inhibitory postsynaptic potentials. When activated by GABA, the GABA receptor/chloride ionophore complex undergoes a conformational change that allows the passage of chloride ions through the channel. Benzodiazepines are believed to exert their effect by increasing the effect of GABA at its receptor. Benzodiazepine binding increases chloride conductance in the presence of GABA by increasing the frequency at which the channel opens. In contrast, barbiturates increase chloride conductance in the presence of GABA by prolonging the time in which the channel remains open. There are 18 subtypes of the GABA receptor subunits. The &alpha;<sub>2</sub> subunit of the &alpha;<sub>2</sub>&beta;<sub>3</sub>&gamma;<sub>2</sub> receptor complex is thought to mediate anxiolytic effects while the &alpha;<sub>1</sub> subunit of the &alpha;<sub>1</sub>&beta;<sub>2</sub>&gamma;<sub>2</sub> receptor complex is thought to mediate sedative, anticonvulsant, and anterograde amnesia effects.
p-Anisic acid, also known as 4-anisate or draconic acid, belongs to the class of organic compounds known as p-methoxybenzoic acids and derivatives. These are benzoic acids in which the hydrogen atom at position 4 of the benzene ring is replaced by a methoxy group. p-Anisic acid is a drug. p-Anisic acid exists in all eukaryotes, ranging from yeast to humans. p-Anisic acid is a faint, sweet, and cadaverous tasting compound. Outside of the human body, p-anisic acid has been detected, but not quantified in several different foods, such as anises, cocoa beans, fennels, and german camomiles. This could make p-anisic acid a potential biomarker for the consumption of these foods. It is a white crystalline solid which is insoluble in water, highly soluble in alcohols and soluble in ether, and ethyl acetate. p-Anisic acid has antiseptic properties. It is also used as an intermediate in the preparation of more complex organic compounds. It is generally obtained by the oxidation of anethole or p-methoxyacetophenone. The term "anisic acid" often refers to this form specifically. p-Anisic acid is found naturally in anise.
p-Toluenesulfonic acid, also known as tosylate or para-toluene sulfonate, is a member of the class of compounds known as p-methylbenzenesulfonates. p-Methylbenzenesulfonates are benzenesulfonic acids (or derivative thereof) carrying a methyl group at the para- position. p-Toluenesulfonic acid is slightly soluble (in water) and an extremely strong acidic compound (based on its pKa). p-Toluenesulfonic acid (PTSA or pTsOH) or tosylic acid (TsOH) is an organic compound with the formula CH3C6H4SO3H. It is a white solid that is soluble in water, alcohols, and other polar organic solvents. The CH3C6H4SO2– group is known as the tosyl group and is often abbreviated as Ts or Tos. Most often, TsOH refers to the monohydrate, TsOH•H2O. It is a white solid that is soluble in water, alcohols, and other polar organic solvents (Wikipedia).
Palmitic acid, or hexadecanoic acid, is one of the most common saturated fatty acids found in animals, plants, and microorganisms. As its name indicates, it is a major component of the oil from the fruit of oil palms (palm oil). Excess carbohydrates in the body are converted to palmitic acid. Palmitic acid is the first fatty acid produced during fatty acid synthesis and is the precursor to longer fatty acids. As a consequence, palmitic acid is a major body component of animals. In humans, one analysis found it to make up 21–30% (molar) of human depot fat (PMID: 13756126), and it is a major, but highly variable, lipid component of human breast milk (PMID: 352132). Palmitic acid is used to produce soaps, cosmetics, and industrial mould release agents. These applications use sodium palmitate, which is commonly obtained by saponification of palm oil. To this end, palm oil, rendered from palm tree (species Elaeis guineensis), is treated with sodium hydroxide (in the form of caustic soda or lye), which causes hydrolysis of the ester groups, yielding glycerol and sodium palmitate. Aluminium salts of palmitic acid and naphthenic acid were combined during World War II to produce napalm. The word "napalm" is derived from the words naphthenic acid and palmitic acid (Wikipedia). Palmitic acid is also used in the determination of water hardness and is a surfactant of Levovist, an intravenous ultrasonic contrast agent.
Palmitoleic acid, or (9Z)-hexadec-9-enoic acid, is an omega-7 monounsaturated fatty acid (16:1n-7) with the formula CH3(CH2)5CH=CH(CH2)7COOH that is a common constituent of the glycerides of human adipose tissue. Present in all tissues, it is generally found in higher concentrations in the liver. Macadamia oil (Macadamia integrifolia) and sea buckthorn oil (Hippophae rhamnoides) are botanical sources of palmitoleic acid, containing 22 and 40% respectively. Palmitoleic acid is found to be associated with isovaleric acidemia, which is an inborn error of metabolism.
In cosmetics, panthenol (also called pantothenol) is a humectant, emollient, and moisturizer. It binds to hair follicles readily and is a frequent component of shampoos and hair conditioners (in concentrations of 0.1-1%). It coats the hair and seals its surface, lubricating follicles and making strands appear shiny. Panthenol (specifically D-panthenol or dexpanthenol) is the alcohol analog of pantothenic acid (vitamin B5), and is thus the provitamin of B5. In organisms, it is quickly oxidized into pantothenate. Panthenol is a viscous transparent liquid at room temperature, but salts of pantothenic acid (for example sodium pantothenate) are powders (typically white). It is very soluble in water, alcohol, and propylene glycol, soluble in ether and chloroform, and only slightly soluble in glycerin.
Pantothenic acid, also called vitamin B5, is a water-soluble vitamin required to sustain life. Pantothenic acid is needed to form coenzyme-A (CoA), and is thus critical in the metabolism and synthesis of carbohydrates, proteins, and fats. Its name is derived from the Greek pantothen meaning "from everywhere" and small quantities of pantothenic acid are found in nearly every food, with high amounts in whole grain cereals, legumes, eggs, meat, and royal jelly. Pantothenic acid is classified as a member of the secondary alcohols. Secondary alcohols are compounds containing a secondary alcohol functional group, with the general structure HOC(R)(R') (R,R'=alkyl, aryl). Pantothenic acid is considered to be soluble (in water) and acidic.
Parabanic Acid, also known as Parabanate or 2,4,5-Imidazolidinetrione, is classified as a member of the Imidazolinones. Imidazolinones are organic compounds containing an imidazolinone moiety, which is an imidazoline ring bearing a ketone. Parabanic Acid is considered to be soluble (in water) and acidic.  Parabanic Acid can be synthesized from imidazolidine. Parabanic Acid can be synthesized into 1-(2-phenylethyl)imidazolidine-2,4,5-trione
Penciclovir is only found in individuals that have used or taken this drug. It is a guanine analogue antiviral drug used for the treatment of various herpesvirus infections. It is a nucleoside analogue which exhibits low toxicity and good selectivity. [Wikipedia]Penciclovir has <i>in vitro</i> activity against herpes simplex virus types 1 (HSV-1) and 2 (HSV-2). In cells infected with HSV-1 or HSV-2, viral thymidine kinase phosphorylates penciclovir to a monophosphate form. The monophosphate form of the drug is then converted to penciclovir triphosphate by cellular kinases. The intracellular triphosphate of penciclovir is retained <i>in vitro</i> inside HSV-infected cells for 10-20 hours, compared with 0.7-1 hour for acyclovir. <i>in vitro</i> studies show that penciclovir triphosphate selectively inhibits viral DNA polymerase by competing with deoxyguanosine triphosphate. Inhibition of DNA synthesis of virus-infected cells inhibits viral replication. In cells not infected with HSV, DNA synthesis is unaltered. Resistant mutants of HSV can occur from qualitative changes in viral thymidine kinase or DNA polymerase. The most commonly encountered acyclovir-resistant mutants that are deficient in viral thymidine kinase are also resistant to penciclovir.
Phenylacetylglutamine is a product formed from the conjugation of phenylacetate and glutamine. Technically, it is the amino acid acetylation product of phenylacetate (or phenylbutyrate after beta-oxidation). Phenylacetylglutamine is a normal constituent of human urine, but other mammals such as the dog, cat, rat, monkey, sheep, and horse do not excrete this compound. Phenylacetyl-CoA and L-glutamine react to form phenylacetylglutamine and coenzyme A. The enzyme (glutamine N-acetyl transferase) that catalyzes this reaction has been purified from human liver mitochondria and shown to be a polypeptide species distinct from glycine-N-acyltransferase. Phenylacetylglutamine is a major nitrogenous metabolite that accumulates in uremia (PMID: 2791363, 8972626). It has been shown that over 50% of urine phenylacetylglutamine may be derived from kidney conjugation of free plasma phenylacetic acid and/or from the kidney's preferential filtration of conjugated phenylacetic acid (PMID: 6420430). Phenylacetylglutamine is a microbial metabolite found in Christensenellaceae, Lachnospiraceae and Ruminococcaceae (PMID: 26241311).
Phenylacetylglycine is an acyl glycine. Acyl glycines are normally minor metabolites of fatty acids. However, the excretion of certain acyl glycines is increased in several inborn errors of metabolism. In certain cases the measurement of these metabolites in body fluids can be used to diagnose disorders associated with mitochondrial fatty acid beta-oxidation. Acyl glycines are produced through the action of glycine N-acyltransferase (EC 2.3.1.13) which is an enzyme that catalyzes the chemical reaction:. acyl-CoA + glycine < -- > CoA + N-acylglycine. Phenylacetylglycine or PAG is a glycine conjugate of phenylacetic acid. Phenylacetic acid may arise from exposure to styrene (plastic) or through the consumption of fruits and vegetables. Phenylacetic acid is used in some perfumes, possessing a honey-like odour in low concentrations, and is also used in penicillin G production. PAG is a putative biomarker of phospholipidosis. Urinary PAG is elevated in animals exhibiting abnormal phospholipid accumulation in many tissues and may thus be useful as a surrogate biomarker for phospholipidosis. (PMID: 15764292) The presence of phenylacetylglycine in urine has been confirmed for dogs, rats and mice. However, the presence of this compound in human urine is controversial. GC-MS studies have not found this compound (PMID: 7492634) while NMR studies claimed to have identified it (PMID: 21167146). It appears that phenylacetylglycine may sometimes be mistaken for phenylacetylglutamine via NMR.
Phloretin is the aglucone of phlorizin, a plant-derived dihydrochalcone phytochemical reported to promote potent antioxidative activities in peroxynitrite scavenging and the inhibition of lipid peroxidation. Phloretin, which is present in apples, pears and tomatoes, has been found to inhibit the growth of several cancer cells and induce apoptosis of B16 melanoma and HL60 human leukemia cells. Phloretin also inhibits HT-29 cell growth by inducing apoptosis, which may be mediated through changes in mitochondrial membrane permeability and activation of the caspase pathways. Phloretin is a well-known inhibitor of eukaryotic urea transporters, blocks VacA-mediated urea and ion transport (PMID:18158826, 11560962, 18063724, 15671209, 12083758). Phloretin is a biomarker for the consumption of apples. Phloretin has been found to be a metabolite of Escherichia (PMID:23542617).
Phthalic acid is an aromatic dicarboxylic acid, with formula C6H4(COOH)2. Phthalic acid is used mainly in the form of the anhydride to produce other chemicals such as dyes, perfumes, saccharin, phthalates and many other useful products. Phthalic acid, when found in tissues or biofluids arises from exposure to these phthalate products. Phthalate is an environmental chemical of heightened public concern because reports of its potential risk to male reproductive health (PMID 16804814), being significantly associated with reduced sperm concentration to pesticide concentration in men's urine (PMID 16804812). Within the reproductive tract, the male is exquisitely vulnerable to the effects of anti-androgens during development due the reliance on the synthesis and action of androgens for the masculinization of the male reproductive tract. The ability of phthalates to suppress androgen synthesis during development and to induce testicular dysgenesis together with cryptorchidism and hypospadias has raised considerable concern. (PMID 15016950).
3,3',4'5-Tetrahydroxystilbene (or Piceatannol) is a phenolic stilbenoid. It is a metabolite of resveratrol found in red wine. A viral protein-tyrosine kinase (LMP2A) implicated in leukemia, non-Hodgkin's lymphoma and other diseases associated with Epstein-Barr virus, was recently found to be blocked by picetannol in vitro (PMID 2590224). Therefore there is research interest in piceatannol as an anti-cancer and anti-EBV drug. Piceatannol can also act as an agonist for estrogen receptor alpha in human breast cancer cells (PMID: 16216908).
Pimelic acid, also known as heptanedioic acid is a dicarboxylic acid.  Derivatives of pimelic acid are involved in the biosynthesis of the amino acid called lysine. Pimelic acid is one methylene longer than a related dicarboxylic acid, adipic acid, a precursor to many polyesters and polyamides. Pimelic acid is essential for the synthesis of biotin (also called vitamin B7). Biotin is a heterocyclic, S-containing monocarboxylic acid that is made from two precursors, alanine and pimeloyl-CoA. Biotin is important in fatty acid synthesis, branched-chain amino acid catabolism, and gluconeogenesis. Biotin is found in a wide range of foods. Likewise, intestinal bacteria synthesize biotin, which is then absorbed by the host animal. Pimelic acid (which is the precursor for pimeloyl-CoA) is synthesized in many bacteria via a head-to-tail incorporation of acetate units through a modified fatty acid synthetic pathway using O-methyl esters disguised to resemble the canonical intermediates of the fatty acid synthetic pathway (PMID:21435937). Some bacteria and yeast synthesize pimelic acid not by biosynthesis, but via cleavage of longer chain fatty acids (such as linolenic acid) via a cytochrome P450-like enzyme (PMID:28196402, 21435937, 3236079). Pimelic acid is excreted in elevated amounts in the urine of individuals with mitochondrial beta-oxidation disorders and peroxisomal beta oxidation disorders (PMID:1527989)
Pioglitazone is used for the treatment of diabetes mellitus type 2. Pioglitazone selectively stimulates nuclear receptor peroxisone proliferator-activated receptor gamma (PPAR-gamma). It modulates the transcription of the insulin-sensitive genes involved in the control of glucose and lipid metabolism in the lipidic, muscular tissues and in the liver.
Piroxicam is only found in individuals that have used or taken this drug. It is a cyclooxygenase inhibiting, non-steroidal anti-inflammatory agent (NSAID) that is well established in treating rheumatoid arthritis and osteoarthritis and used for musculoskeletal disorders, dysmenorrhea, and postoperative pain. Its long half-life enables it to be administered once daily. [PubChem]The antiinflammatory effect of Piroxicam may result from the reversible inhibition of cyclooxygenase, causing the peripheral inhibition of prostaglandin synthesis. The prostaglandins are produced by an enzyme called Cox-1. Piroxicam blocks the Cox-1 enzyme, resulting into the disruption of production of prostaglandins. Piroxicam also inhibits the migration of leukocytes into sites of inflammation and prevents the formation of thromboxane A2, an aggregating agent, by the platelets.
Most statins are metabolised in part by one or more hepatic cytochrome P450 enzymes, leading to an increased potential for drug interactions and problems with certain foods (such as grapefruit juice). Pitavastatin appears to be a substrate of CYP2C9, and not CYP3A4 (which is a common source of interactions in other statins). As a result, pitavastatin is less likely to interact with drugs that are metabolized via CYP3A4, which might be important for elderly patients who need to take multiple medicines. Pitavastatin (usually as a calcium salt) is a member of the medication class of statins, marketed in the United States under the trade name Livalo. Like other statins, it is an inhibitor of HMG-CoA reductase, the enzyme that catalyses the first step of cholesterol synthesis. It has been available in Japan since 2003, and is being marketed under licence in South Korea and in India. It is likely that pitavastatin will be approved for use in hypercholesterolaemia (elevated levels of cholesterol in the blood) and for the prevention of cardiovascular disease outside South and Southeast Asia as well.
Porphobilinogen (PBG) is a pyrrole-containing intermediate in the biosynthesis of porphyrins. It is generated from aminolevulinate (ALA) by the enzyme ALA dehydratase. Porphobilinogen is then converted into hydroxymethylbilane by the enzyme porphobilinogen deaminase (also known as hydroxymethylbilane synthase). Under certain conditions, porphobilinogen can act as a phototoxin, a neurotoxin, and a metabotoxin. A phototoxin leads to cell damage upon exposure to light. A neurotoxin causes damage to nerve cells and nerve tissues. A metabotoxin is an endogenously produced metabolite that causes adverse health effects at chronically high levels. Chronically high levels of porphyrins are associated with porphyrias such as porphyria variegate, acute intermittent porphyria, and hereditary coproporphyria (HCP). There are several types of porphyrias (most are inherited). Hepatic porphyrias are characterized by acute neurological attacks (seizures, psychosis, extreme back and abdominal pain, and an acute polyneuropathy), while the erythropoietic forms present with skin problems (usually a light-sensitive blistering rash and increased hair growth). The neurotoxicity of porphyrins may be due to their selective interactions with tubulin, which disrupt microtubule formation and cause neural malformations (PMID: 3441503).
Pravastatin is a member of the drug class of statins, used for lowering cholesterol and preventing cardiovascular disease. Pravastatin was identified originally in a mold called Nocardia autotrophica by researchers of the Sankyo Pharma Inc; An antilipemic fungal metabolite isolated from cultures of Nocardia autotrophica. It acts as a competitive inhibitor of HMG CoA reductase (hydroxymethylglutaryl CoA reductases); In medicine and pharmacology, pravastatin (Pravachol or Selektine) is a member of the drug class of statins, used for lowering cholesterol and preventing cardiovascular disease.
Prazosin is a selective &alpha;-<sub>1</sub>-adrenergic receptor antagonist used to treat hypertension. It has also been used to decrease urinary obstruction and relieve symptoms associated with symptomatic benign prostatic hyperplasia. &alpha;<sub>1</sub>-Receptors mediate contraction and hypertrophic growth of smooth muscle cells. Antagonism of these receptors leads to smooth muscle relaxation in the peripheral vasculature and prostate gland. Prazosin has also been used in conjunction with cardiac glycosides and diuretics in the management of severe congestive heart failure. It has also been used alone or in combination with &beta;-blockers in the preoperative management of signs and symptoms of pheochromocytoma.
Prolylhydroxyproline is a dipeptide. Prolylhydroxyproline is a marker of bone collagen degradation, showing high sensitivity for the diagnosis of osteoporosis. Prolylhydroxyproline has been suggested as a possible alternative to hydroxyproline determination in bone resorption studies. Prolylhydroxyproline is one of the iminodipeptides present in the urine of patients with prolidase deficiency. Prolidase (X-Pro dipeptidase EC 3.4.13.9) splits iminodipeptides containing C-terminal proline or hydroxyproline (X-Pro or X-Hyp) to X+Pro or X+Hyp. Prolidase deficiency is a rare autosomal recessive disease characterized by chronic ulcerative dermatitis and mental retardation. These patients excrete large amounts of iminodipeptides containing C-terminal proline in the urine due to hereditary prolidase deficiency (PMID: 12636053, 11863289, 2387877, 1874885, 9586797).
Pseudouridine, also known as psi-uridine or 5-ribosyluracil, belongs to the class of organic compounds known as nucleoside and nucleotide analogues. These are analogues of nucleosides and nucleotides, such as phosphonated nucleosides, C-glycosylated nucleoside bases, analogues where the sugar unit is a pyranose, and carbocyclic nucleosides.  Pseudouridine specifically has its uracil attached via a carbon-carbon instead of a nitrogen-carbon glycosidic bond to the ribofuranose.  It is the most prevalent of the over one hundred different modified nucleosides found in RNA (PMID: 17113994).  Pseudouridine is a solid that is soluble in water.  Pseudouridine exists in all living species, ranging from bacteria to humans, and is in all classes of RNA except mRNA.  It is formed by enzymes called pseudouridine synthases, which post-transcriptionally isomerize specific uridine residues in RNA.
Purine, also known as purine base or 1H-purine, belongs to the class of organic compounds known as purines and purine derivatives. These are aromatic heterocyclic compounds containing a purine moiety, which is formed a pyrimidine-ring ring fused to an imidazole ring. Two of the bases in nucleic acids, adenine and guanine, are purines. Purines from food (or from tissue turnover) are metabolised by several enzymes, including xanthine oxidase, into uric acid. Purine exists in all living species, ranging from bacteria to humans. High levels of uric acid can predispose to gout when the acid crystalises in joints; this phenomenon only happens in humans and some animal species (e.g. dogs) that lack an intrinsic uricase enzyme that can further degrade uric acid. In humans, purine is involved in thioguanine action pathway. Outside of the human body, purine is found, on average, in the highest concentration within cocoa beans. Purine has also been detected, but not quantified in several different foods, such as rapinis, plains prickly pears, blackcurrants, radish, and parsley. This could make purine a potential biomarker for the consumption of these foods. Purine is a heterocyclic aromatic organic compound, consisting of a pyrimidine ring fused to an imidazole ring.
Pyrocatechol, often known as catechol or benzene-1,2-diol, is a benzenediol, with formula C6H4(OH)2. It was first prepared in 1839 by H. Reinsch by distilling catechin (the juice of Mimosa catechu). This colourless compound occurs naturally, but about 20000 tons are manufactured each year, mainly as precursors to pesticides, flavors, and fragrances. Its sulfonic acid is often present in the urine of many mammals. Small amounts of catechol occur naturally in fruits and vegetables, along with the enzyme polyphenol oxidase. Upon mixing the enzyme with the substrate and exposure to oxygen (as when a potato or apple is cut), the colorless catechol oxidizes to reddish-brown benzoquinone derivatives. The enzyme is inactivated by adding an acid, such as lemon juice, or by refrigeration. Excluding oxygen also prevents the browning reaction. Catechol melts at 28 °C and boils at 250 °C. It is employed in medicine as an expectorant. The dimethyl ether or veratrol is also used in medicine. Many other pyrocatechin derivatives have been suggested for therapeutic application. Pyrocatechol has also been found to be a microbial metabolite in Escherichia, Mycobacterium and Pseudomonas (PMID:19300498; PMID:25281236).
1,2,3-Trihydroxybenzene, or pyrogallol is a benzenetriol. It is a white crystalline powder and a powerful reducing agent. It was first prepared by Scheele 1786 by heating gallic acid. An alternate preparation is heating para-chlorophenoldisulphonic acid with potassium hydroxide. 1,2,3-Trihydroxybenzene has been found to be a metabolite of Aspergillus (https://www.tandfonline.com/doi/pdf/10.1080/00021369.1982.10865473).
Pyrrole-2-carboxylic acid was synthesized over a century ago, but its history as a compound of biological origin is rather recent. It was first identified as a degradation product of sialic acids, then as a derivative of the oxidation of the D-hydroxyproline isomers by mammalian D-amino acid oxidase. The latter relationship results from the lability of the direct oxidation product, A'-pyrroline-4-hydroxy-2-carboxylic acid, which loses water spontaneously to form the pyrrole. A similar reaction is catalyzed by the more specific allohydroxy-D-proline oxidase of Pseudomonas. In whole animal observations, pyrrole-2-carboxylate (PCA) ' was identified in rat or human urine after administration of the D-isomers of hydroxyproline, a finding ascribable to the action of D-amino acid oxidase. (PMID:4430715). Urinary excretion of N-(pyrrole-2-carboxyl) glycine has been reported in a 5-year-old affected with type II hyperprolinemia; The child has mild developmental delay, recurrent seizures of the grand mal type and EEG alterations. The urinary excretion of the conjugate is stressed, since it appears that only one previous report in the literature described this compound in the urine of two patients affected by this disturbance (PMID 2383933).
Quercetin 3-O-(6''-acetyl-glucoside) is a polyphenol compound found in foods of plant origin  (PMID: 20428313)
Quercetin is a flavonoid widely distributed in many plants and fruits including red grapes, citrus fruit, tomato, broccoli and other leafy green vegetables, and a number of berries, including raspberries and cranberries. Quercetin itself (aglycone quercetin), as opposed to quercetin glycosides, is not a normal dietary component. Quercetin glycosides are converted to phenolic acids as they pass through the gastrointestinal tract. Quercetin has neither been confirmed scientifically as a specific therapeutic for any condition nor been approved by any regulatory agency. The U.S. Food and Drug Administration has not approved any health claims for quercetin. Nevertheless, the interest in dietary flavonoids has grown after the publication of several epidemiological studies showing an inverse correlation between dietary consumption of flavonols and flavones and reduced incidence and mortality from cardiovascular disease and cancer. In recent years, a large amount of experimental and some clinical data have accumulated regarding the effects of flavonoids on the endothelium under physiological and pathological conditions. The meta-analysis of seven prospective cohort studies concluded that the individuals in the top third of dietary flavonol intake are associated with a reduced risk of mortality from coronary heart disease as compared with those in the bottom third, after adjustment for known risk factors and other dietary components. A limited number of intervention studies with flavonoids and flavonoid containing foods and extracts has been performed in several pathological conditions (PMID:17015250).
Raffinose is a complex carbohydrate. It is a trisaccharide composed of galactose, fructose, and glucose. It can be found in beans, cabbage, brussels sprouts, broccoli, asparagus, other vegetables, and whole grains. Raffinose is hydrolyzed to D-galactose and sucrose by D-galactosidase (D-GAL). D-GAL also hydrolyzes other D-galactosides such as stachyose, verbascose, and galactinol [1-O-(D-galactosyl)-myoinositol], if present. The enzyme does not cleave linked galactose, as in lactose. Raffinose is also known as melitose and may be thought of as galactose and sucrose connected via an alpha(1->6) glycosidic linkage. Thus, raffinose can be broken down into galactose and sucrose via the enzyme alpha-galactosidase. Human intestines do not contain this enzyme. Raffinose is a trisaccharide occurring in Australian manna (from Eucalyptus spp, Myrtaceae) and in cottonseed meal.
Raltitrexed is only found in individuals that have used or taken this drug. It is a chemotherapy drug manufactured AstraZeneca Company, is an antimetabolite used in chemotherapy. It is an inhibitor of thymidylate synthase.Raltitrexed is an antineoplastic Agents and folic acid antagonists. Raltitrexed inhibits thymidylate synthase (TS) leading to DNA fragmentation and cell death. It is transported into cells via a reduced folate carrier. Inside the cell Raltitrexed is extensively polyglutamated, which enhances thymidylate synthase inhibitory power and duration. Inhibition of this enzyme results in decreased synthesis of thymidine triphosphate which is required for DNA synthesis.
Ramipril is a prodrug belonging to the angiotensin-converting enzyme (ACE) inhibitor class of medications. It is metabolized to ramiprilat in the liver and, to a lesser extent, kidneys. Ramiprilat is a potent, competitive inhibitor of ACE, the enzyme responsible for the conversion of angiotensin I (ATI) to angiotensin II (ATII). ATII regulates blood pressure and is a key component of the renin-angiotensin-aldosterone system (RAAS). Ramipril may be used in the treatment of hypertension, congestive heart failure, nephropathy, and to reduce the rate of death, myocardial infarction and stroke in individuals at high risk of cardiovascular events.
Ranitidine (CAS: 66357-35-5) is a non-imidazole blocker of histamine receptors that mediate gastric secretion (H2 receptors). It is used to treat gastrointestinal ulcers (PubChem). Ranitidine is a histamine H2-receptor antagonist that inhibits stomach acid production and is commonly used in the treatment of peptic ulcer disease (PUD) and gastroesophageal reflux disease (GERD). It is currently marketed by GlaxoSmithKline under the trade name Zantac (Wikipedia).
Ranolazine is only found in individuals that have used or taken this drug. It is an antianginal medication. On January 31, 2006, ranolazine was approved for use in the United States by the FDA for the treatment of chronic angina. [Wikipedia]The mechanism of action of ranolazine is unknown. It does not increase the rate-pressure product, a measure of myocardial work, at maximal exercise. In vitro studies suggest that ranolazine is a P-gp inhibitor. Ranolazine is believed to have its effects via altering the trans-cellular late sodium current. It is by altering the intracellular sodium level that ranolazine affects the sodium-dependent calcium channels during myocardial ischemia. Thus, ranolazine indirectly prevents the calcium overload that causes cardiac ischemia.
Repaglinide is an oral antihyperglycemic agent used for the treatment of non-insulin-dependent diabetes mellitus (NIDDM). It belongs to the meglitinide class of short-acting insulin secretagogues, which act by binding to cells of the pancreas to stimulate insulin release. Repaglinide induces an early insulin response to meals decreasing postprandial blood glucose levels. It should only be taken with meals and meal-time doses should be skipped with any skipped meal. Approximately one month of therapy is required before a decrease in fasting blood glucose is seen. Meglitnides may have a neutral effect on weight or cause a slight increase in weight. The average weight gain caused by meglitinides appears to be lower than that caused by sulfonylureas and insulin and appears to occur only in those naive to oral antidiabetic agents. Due to their mechanism of action, meglitinides may cause hypoglycemia although the risk is thought to be lower than that of sulfonylureas since their action is dependent on the presence of glucose. In addition to reducing postprandial and fasting blood glucose, meglitnides have been shown to decrease glycosylated hemoglobin (HbA1c) levels, which are reflective of the last 8-10 weeks of glucose control. Meglitinides appear to be more effective at lowering postprandial blood glucose than metformin, sulfonylureas and thiazolidinediones. Repaglinide is extensively metabolized in the liver and excreted in bile. Repaglinide metabolites do not possess appreciable hypoglycemic activity. Approximately 90% of a single orally administered dose is eliminated in feces and 8% in urine.
all-trans-Retinoic acid is an isomer of retinoic acid, the oxidized form of vitamin A. Retinoic acid functions in determining position along embryonic anterior/posterior axis in chordates. It acts through Hox genes, which ultimately controls anterior/posterior patterning in early developmental stages (PMID:17495912). It is an important regulator of gene expression during growth and development, and in neoplasms. As a drug, all-trans-retinoic acid is known as tretinoin. Tretinoin is derived from maternal vitamin A and is essential for normal growth and embryonic development. An excess of tretinoin can be teratogenic. Tretinoin is used in the treatment of psoriasis, acne vulgaris, and several other skin diseases. It has also been approved for use in promyelocytic leukemia (leukemia, promyelocytic, acute).
Riboflavin or vitamin B2 is an easily absorbed, water-soluble micronutrient with a key role in maintaining human health. Like the other B vitamins, it supports energy production by aiding in the metabolizing of fats, carbohydrates, and proteins. Vitamin B2 is also required for red blood cell formation and respiration, antibody production, and for regulating human growth and reproduction. It is essential for healthy skin, nails, hair growth and general good health, including regulating thyroid activity. Riboflavin is found in milk, eggs, malted barley, liver, kidney, heart, and leafy vegetables. Riboflavin is yellow or orange-yellow in color and in addition to being used as a food coloring it is also used to fortify some foods. It can be found in baby foods, breakfast cereals, sauces, processed cheese, fruit drinks and vitamin-enriched milk products. The richest natural source is yeast. It occurs in the free form only in the retina of the eye, in whey, and in urine; its principal forms in tissues and cells are as flavin mononucleotide and flavin adenine dinucleotide.
Riluzole is only found in individuals that have used or taken this drug. It is a glutamate antagonist (receptors, glutamate) used as an anticonvulsant (anticonvulsants) and to prolong the survival of patients with amyotrophic lateral sclerosis. [PubChem]The mode of action of riluzole is unknown. Its pharmacological properties include the following, some of which may be related to its effect: 1) an inhibitory effect on glutamate release (activation of glutamate reuptake), 2) inactivation of voltage-dependent sodium channels, and 3) ability to interfere with intracellular events that follow transmitter binding at excitatory amino acid receptors.
Ritonavir is only found in individuals that have used or taken this drug. It is an HIV protease inhibitor that works by interfering with the reproductive cycle of HIV. [PubChem]Ritonavir inhibits the HIV viral proteinase enzyme which prevents cleavage of the gag-pol polyprotein, resulting in noninfectious, immature viral particles.
Rizatriptan is only found in individuals that have used or taken this drug. It is a triptan drug used for the treatment of migraine headaches. It is a selective 5-hydroxytryptamine1 receptor subtype agonist.Three distinct pharmacological actions have been implicated in the antimigraine effect of the triptans: (1) stimulation of presynaptic 5-HT1D receptors, which serves to inhibit both dural vasodilation and inflammation; (2) direct inhibition of trigeminal nuclei cell excitability via 5-HT1B/1D receptor agonism in the brainstem and (3) vasoconstriction of meningeal, dural, cerebral or pial vessels as a result of vascular 5-HT1B receptor agonism.
Rosiglitazone is an anti-diabetic drug from the thiazolidinedione class. Like other thiazolidinediones, its mechanism of action is by activation of the intracellular receptor class of the peroxisome proliferator-activated receptors (PPARs), specifically PPAR-gamma. Rosiglitazone is a pure ligand of PPAR-gamma, and has no PPAR-alpha-binding action. Apart from its effect on insulin resistance, it appears to have an anti-inflammatory effect: nuclear factor kappa-B (NF&#954;B) levels fall and inhibitor (I&#954;B) levels increase in patients on rosiglitazone (Mohanty et al). It increases glyceroneogenesis and reduces the release of free fatty acids from adipocytes; Rosiglitazone is an anti-diabetic drug from the thiazolidinedione class. It is being marketed as Avandia by the pharmaceutical company GlaxoSmithKline, both as a standalone preparation and in combination with metformin (Avandamet). Another combination drug approved by the FDA is Avandaryl (with glimepiride); Like other thiazolidinediones, its mechanism of action is by activation of the intracellular receptor class of the peroxisome proliferator-activated receptors (PPARs), specifically PPAR-gamma. Rosiglitazone is a pure ligand of PPAR-gamma, and has no PPAR-alpha binding action. Apart from its effect on insulin resistance, it appears to have an anti-inflammatory effect: nuclear factor kappa-B (NFkB) levels fall and inhibitor (IkB) levels increase in patients on rosiglitazone (Mohanty et al). It increases glyceroneogenesis and reduces the release of free fatty acids from adipocytes.
Rutin is a flavonoid known to have a variety of biological activities including antiallergic, anti-inflammatory, antiproliferative, and anticarcinogenic properties. A large number of flavonoids, mostly O-glycosides, are polyphenolic compounds of natural origin that are present in most fruits and vegetables. The average intake of the compounds by humans on a normal diet is more than 1 g per day. Although flavonoids are devoid of classical nutritional value, they are increasingly viewed as beneficial dietary components that act as potential protectors against human diseases such as coronary heart disease, cancers, and inflammatory bowel disease. Rutin acts as a quercetin deliverer to the large intestine; moreover, quercetin is extensively metabolized in the large intestine, which suggests that quercetin liberated from rutin and/or its colonic metabolites may play a role. Rutin's anti-inflammatory actions are mediated through a molecular mechanism that underlies the quercetin-mediated therapeutic effects: quercetin-mediated inhibition of tumor necrosis factor-alpha (TNF-alpha)-induced nuclear factor kappa B (NFkB) activation. TNF-alpha-induced NFkB activity plays a central role in the production of pro-inflammatory mediators involved in progression of gut inflammation. (PMID:16132362).
Salbutamol is a short-acting, selective beta2-adrenergic receptor agonist used in the treatment of asthma and COPD. It is 29 times more selective for beta2 receptors than beta1 receptors giving it higher specificity for pulmonary beta receptors versus beta1-adrenergic receptors located in the heart. Salbutamol is formulated as a racemic mixture of the R- and S-isomers. The R-isomer has 150 times greater affinity for the beta2-receptor than the S-isomer and the S-isomer has been associated with toxicity. This lead to the development of levalbuterol, the single R-isomer of salbutamol. However, the high cost of levalbuterol compared to salbutamol has deterred wide-spread use of this enantiomerically pure version of the drug. Salbutamol is generally used for acute episodes of bronchospasm caused by bronchial asthma, chronic bronchitis and other chronic bronchopulmonary disorders such as chronic obstructive pulmonary disorder (COPD). It is also used prophylactically for exercise-induced asthma
Salicin, also known as salicoside or delta-salicin, is an aryl beta-D-glucoside that is salicyl alcohol in which the phenolic hydrogen has been replaced by a beta-D-glucosyl residue. It has a role as a prodrug, an antipyretic, a non-narcotic analgesic, a non-steroidal anti-inflammatory drug, an EC 1.14.99.1 (prostaglandin-endoperoxide synthase) inhibitor and a metabolite. It is an aryl beta-D-glucoside, an aromatic primary alcohol and a member of benzyl alcohols. It derives from a salicyl alcohol.  Salicin belongs to the class of organic compounds known as phenolic glycosides. These are organic compounds containing a phenolic structure attached to a glycosyl moiety. Some examples of phenolic structures include lignans, and flavonoids. Among the sugar units found in natural glycosides are D-glucose, L-Fructose, and L rhamnose. Salicin exists in all living organisms, ranging from bacteria to humans. Salicin is a bitter tasting compound.
Salicylic acid is a monohydroxybenzoic acid that is benzoic acid with a hydroxy group at the ortho position. It is obtained from the bark of the white willow and wintergreen leaves. It has a role as an antiinfective agent, an antifungal agent, a keratolytic drug, an EC 1.11.1.11 (L-ascorbate peroxidase) inhibitor, a plant metabolite, an algal metabolite and a plant hormone. It is a conjugate acid of a salicylate. It is a colorless solid, it is a precursor to and a metabolite of aspirin (acetylsalicylic acid). It is a plant hormone. The name is from Latin salix for willow tree. It is an ingredient in some anti-acne products. Salts and esters of salicylic acid are known as salicylates. Salicylic acid modulates COX1 enzymatic activity to decrease the formation of pro-inflammatory prostaglandins. Salicylate may competitively inhibit prostaglandin formation. Salicylate's antirheumatic (nonsteroidal anti-inflammatory) actions are a result of its analgesic and anti-inflammatory mechanisms. Salicylic acid works by causing the cells of the epidermis to slough off more readily, preventing pores from clogging up, and allowing room for new cell growth. Salicylic acid inhibits the oxidation of uridine-5-diphosphoglucose (UDPG) competitively with nicotinamide adenosine dinucleotide and noncompetitively with UDPG. It also competitively inhibits the transferring of glucuronyl group of uridine-5-phosphoglucuronic acid to the phenolic acceptor. The wound-healing retardation action of salicylates is probably due mainly to its inhibitory action on mucopolysaccharide synthesis. Salicylic acid is biosynthesized from the amino acid phenylalanine. In Arabidopsis thaliana, it can be synthesized via a phenylalanine-independent pathway.
2-Hydroxybenzyl alcohol (CAS Number 90-01-7) is a stable light brown crystalline powder.
Salmeterol is only found in individuals that have used or taken this drug. It is a long-acting beta2-adrenergic receptor agonist drug that is currently prescribed for the treatment of asthma and chronic obstructive pulmonary disease COPD. Salmeterol's long, lipophilic side chain binds to exosites near beta(2)-receptors in the lungs and on bronchiolar smooth muscle, allowing the active portion of the molecule to remain at the receptor site, continually binding and releasing. Beta(2)-receptor stimulation in the lung causes relaxation of bronchial smooth muscle, bronchodilation, and increased bronchial airflow.
Scopoletin is found in anise. Scopoletin is isolated from Angelica acutiloba (Dong Dang Gui
Secobarbital is only found in individuals that have used or taken this drug. It is a barbiturate derivative drug. It possesses anaesthetic, anticonvulsant, sedative and hypnotic properties. In the United Kingdom, it was known as Quinalbarbitone. Secobarbital binds at a distinct binding site associated with a Cl<sup>-</sup> ionopore at the GABA<sub>A</sub> receptor, increasing the duration of time for which the Cl<sup>-</sup> ionopore is open. The post-synaptic inhibitory effect of GABA in the thalamus is, therefore, prolonged.
Secoisolariciresinol is a lignan, a type of phenylpropanoids.
Sinapic acid, also known as sinapinate, belongs to the class of organic compounds known as hydroxycinnamic acids. Hydroxycinnamic acids are compounds containing an cinnamic acid where the benzene ring is hydroxylated. Sinapic acid has been detected, but not quantified, in several different foods, such as strawberry guava, purple lavers, common verbena, ryes, and lupines. This could make sinapic acid a potential biomarker for the consumption of these foods. A sinapic acid in which the double bond has trans-configuration.
Sinapyl alcohol is an organic compound derived from cinnamic acid. This phytochemical is one of the monolignols. It is biosynthetized via the phenylpropanoid biochemical pathway, its immediate precursor being sinapaldehyde. Sinapyl alcohol is a precursor to lignin or lignans. It is also a biosynthetic precursor to various stilbenes and coumarins.[From Wiki].
Sotalol is only found in individuals that have used or taken this drug. It is an adrenergic beta-antagonist that is used in the treatment of life-threatening arrhythmias (PubChem). Sotalol has both beta-adrenoreceptor blocking (Vaughan Williams Class I) and cardiac action potential duration prolongation (Vaughan Williams Class I) antiarrhythmic properties. Sotalol is a racemic mixture of d- and l-sotalol. Both isomers have similar Class I antiarrhythmic effects, while the l-isomer is responsible for virtually all of the beta-blocking activity. Sotalol inhibits response to adrenergic stimuli by competitively blocking &#946;<sub>1</sub>-adrenergic receptors within the myocardium and &#946;<sub>2</sub>-adrenergic receptors within bronchial and vascular smooth muscle. The electrophysiologic effects of sotalol may be due to its selective inhibition of the rapidly activating component of the potassium channel involved in the repolarization of cardiac cells. The class II electrophysiologic effects are caused by an increase in sinus cycle length (slowed heart rate), decreased AV nodal conduction, and increased AV nodal refractoriness, while the class III electrophysiological effects include prolongation of the atrial and ventricular monophasic action potentials, and effective refractory period prolongation of atrial muscle, ventricular muscle, and atrio-ventricular accessory pathways (where present) in both the anterograde and retrograde directions.
Sorbitol is a polyhydric alcohol with about half the sweetness of sucrose. Sorbitol occurs naturally and is also produced synthetically from glucose. It was formerly used as a diuretic and may still be used as a laxative and in irrigating solutions for some surgical procedures. It is also used in many manufacturing processes, as a pharmaceutical aid, and in several research applications. Ascorbic acid fermentation; in solution form for moisture-conditioning of cosmetic creams and lotions, toothpaste, tobacco, gelatin; bodying agent for paper, textiles, and liquid pharmaceuticals; softener for candy; sugar crystallization inhibitor; surfactants; urethane resins and rigid foams; plasticizer, stabilizer for vinyl resins; food additive (sweetener, humectant, emulsifier, thickener, anticaking agent); dietary supplement. (Hawley's Condensed Chemical Dictionary) Biological Source: Occurs widely in plants ranging from algae to the higher orders. Fruits of the plant family Rosaceae, which include apples, pears, cherries, apricots, contain appreciable amounts. Rich sources are the fruits of the Sorbus and Crataegus species Use/Importance: Used for manufacturing of sorbose, propylene glycol, ascorbic acid, resins, plasticizers and as antifreeze mixtures with glycerol or glycol. Tablet diluent, sweetening agent and humectant, other food uses. Sorbitol is used in photometric determination of Ru(VI) and Ru(VIII); in acid-base titration of borate (Dictionary of Organic Compounds).
Stavudine is only found in individuals that have used or taken this drug. It is a dideoxynucleoside analog that inhibits reverse transcriptase and has in vitro activity against HIV. [PubChem]Stavudine inhibits the activity of HIV-1 reverse transcriptase (RT) both by competing with the natural substrate dGTP and by its incorporation into viral DNA.
Stearic acid, also known as octadecanoic acid or C18:0, belongs to the class of organic compounds known as long-chain fatty acids. These are fatty acids with an aliphatic tail that contains between 13 and 21 carbon atoms. Stearic acid (its ester is called stearate) is a saturated fatty acid that has 18 carbons and is therefore a very hydrophobic molecule that is practically insoluble in water.  It exists as a waxy solid.  In terms of its biosynthesis, stearic acid is produced from carbohydrates via the fatty acid synthesis machinery wherein acetyl-CoA contributes two-carbon building blocks, up to the 16-carbon palmitate, via the enzyme complex fatty acid synthase (FA synthase), at which point a fatty acid elongase is needed to further lengthen it.  After synthesis, there are a variety of reactions it may undergo, including desaturation to oleate via stearoyl-CoA desaturase (PMID: 16477801).  Stearic acid is found in all living organisms ranging from bacteria to plants to animals.  It is one of the useful types of saturated fatty acids that comes from many animal and vegetable fats and oils. For example, it is a component of cocoa butter and shea butter.  It is used as a food additive, in cleaning and personal care products, and in lubricants.  Its name comes from the Greek word stear, which means ‚Äòtallow‚Äô or ‚Äòhard fat‚Äô.
Sucrose is a nonreducing disaccharide composed of glucose and fructose linked via their anomeric carbons. It is obtained commercially from sugarcane (Saccharum officinarum), sugar beet (Beta vulgaris), and other plants and used extensively as a food and a sweetener. Sucrose is derived by crushing and extracting sugarcane with water or by extracting sugar beet with water, evaporating, and purifying with lime, carbon, and various liquids. Sucrose is also obtainable from sorghum. Sucrose occurs in low percentages in honey and maple syrup. Sucrose is used as a sweetener in foods and soft drinks, in the manufacture of syrups, in invert sugar, confectionery, preserves and jams, demulcent, pharmaceutical products, and caramel. Sucrose is also a chemical intermediate for detergents, emulsifying agents, and other sucrose derivatives. Sucrose is widespread in the seeds, leaves, fruits, flowers, and roots of plants, where it functions as an energy store for metabolism and as a carbon source for biosynthesis. The annual world production of sucrose is in excess of 90 million tons mainly from the juice of sugar cane (20%) and sugar beet (17%). In addition to its use as a sweetener, sucrose is used in food products as a preservative, antioxidant, moisture control agent, stabilizer, and thickening agent. BioTransformer predicts that sucrose is a product of 6-O-sinapoyl sucrose metabolism via a hydrolysis-of-carboxylic-acid-ester-pattern1 reaction occurring in human gut microbiota and catalyzed by the liver carboxylesterase 1 (P23141) enzyme (PMID: 30612223).
Oftentimes, serotonin levels in the brain become extremely erratic before the onset of a migraine. In an attempt to stabilize this, sumatriptan is administered to help aid in leveling the serotonin levels in the brain. Sumatriptan is structurally similar to serotonin, and is a 5-HT (5-HT1D) agonist, which is one of the receptors that serotonin binds to. The specific receptor subtype it activates is present in the cranial and basilar arteries. Activation of these receptors causes vasoconstriction of those dilated arteries. Sumatriptan is also shown to decrease the activity of the trigeminal nerve. Sumatriptan is a triptan drug including a sulfonamide group structurally similar to serotonin, and is a 5-HT (5-HT1D) agonist, which is one of the receptors that serotonin binds to. Oftentimes, serotonin levels in the brain become extremely erratic before the onset of a migraine. In an attempt to stabilize this, sumatriptan is administered to help aid in leveling the serotonin levels in the brain. A serotonin agonist that acts selectively at 5HT1 receptors. It is used in the treatment of migraines. Sumatriptan (Imitrex, Imigran, Imigran Recovery) is a triptan drug including a sulfonamide group which was originally developed by Glaxo for the treatment of migraine headaches.
Syringic acid, also known as syringate or cedar acid, belongs to the class of organic compounds known as gallic acid and derivatives. Gallic acid and derivatives are compounds containing a 3,4,5-trihydroxybenzoic acid moiety. Outside of the human body, Syringic acid is found, on average, in the highest concentration within a few different foods, such as common walnuts, swiss chards, and olives and in a lower concentration in apples, tarragons, and peanuts. Syringic acid has also been detected, but not quantified in several different foods, such as sweet marjorams, silver lindens, bulgurs, annual wild rices, and barley. This could make syringic acid a potential biomarker for the consumption of these foods. Syringic acid is correlated with high antioxidant activity and inhibition of LDL oxidation. Research suggests that phenolics from wine may play a positive role against oxidation of low-density lipoprotein (LDL), which is a key step in the development of atherosclerosis. Syringic acid is a phenol present in some distilled alcohol beverages. It is also a product of microbial (gut) metabolism of anthocyanins and other polyphenols that have been consumed (in fruits and alcoholic beverages - PMID:18767860). Syringic acid is also a microbial metabolite that can be found in Bifidobacterium (PMID:24958563).
Tacrolimus (also FK-506 or Fujimycin) is an immunosuppressive drug whose main use is after organ transplant to reduce the activity of the patient's immune system and so the risk of organ rejection. It is also used in a topical preparation in the treatment of severe atopic dermatitis, severe refractory uveitis after bone marrow transplants, and the skin condition vitiligo. It was discovered in 1984 from the fermentation broth of a Japanese soil sample that contained the bacteria Streptomyces tsukubaensis. Tacrolimus is chemically known as a macrolide. It reduces peptidyl-prolyl isomerase activity by binding to the immunophilin FKBP-12 (FK506 binding protein) creating a new complex. This FKBP12-FK506 complex interacts with and inhibits calcineurin thus inhibiting both T-lymphocyte signal transduction and IL-2 transcription.
Tadalafil is an orally adminstered drug used to treat male erectile dysfunction (impotence). It is marketed worldwide under the brand name Cialis. It is a phosphodiesterase 5 (PDE5) inhibitor. Tadalafil's distinguishing pharmacologic feature is its longer half-life (17.5 hours) compared with Viagra and Levitra (4-5 hours). This longer half-life results in a longer duration of action and is, in part, responsible for the Cialis nickname of the 'weekend pill.' This longer half-life also is the basis of current investigation for tadalafil's use in pulmonary arterial hypertension as a once-daily therapy. [Wikipedia]
Taurocholic acid is a bile acid and is the product of the conjugation of cholic acid with taurine. Its sodium salt is the chief ingredient of the bile of carnivorous animals. Bile acids are steroid acids found predominantly in the bile of mammals. The distinction between different bile acids is minute, depending only on the presence or absence of hydroxyl groups on positions 3, 7, and 12. Bile acids are physiological detergents that facilitate excretion, absorption, and transport of fats and sterols in the intestine and liver. Bile acids are also steroidal amphipathic molecules derived from the catabolism of cholesterol. They modulate bile flow and lipid secretion, are essential for the absorption of dietary fats and vitamins, and have been implicated in the regulation of all the key enzymes involved in cholesterol homeostasis. Bile acids recirculate through the liver, bile ducts, small intestine, and portal vein to form an enterohepatic circuit. They exist as anions at physiological pH, and consequently require a carrier for transport across the membranes of the enterohepatic tissues. The unique detergent properties of bile acids are essential for the digestion and intestinal absorption of hydrophobic nutrients. Bile acids have potent toxic properties (e.g. membrane disruption) and there are a plethora of mechanisms to limit their accumulation in blood and tissues (PMID: 11316487, 16037564, 12576301, 11907135). Taurocholic acid, as with all bile acids, acts as a detergent to solubilize fats for absorption and is itself absorbed. It is used as a cholagogue and choleretic (a bile purging agent). Hydrolysis of taurocholic acid yields taurine, a nonessential amino acid. Taurocholic acid is one of the main components of urinary nonsulfated bile acids in biliary atresia. Raised levels of taurocholate in fetal serum in obstetric cholestasis may result in the development of a fetal dysrhythmia and sudden intra-uterine death (PMID: 3944741, 11256973).
Telmisartan is an angiotensin II receptor antagonist (ARB) used in the management of hypertension. Generally, angiotensin II receptor blockers (ARBs) such as telmisartan bind to the angiotensin II type 1 (AT1) receptors with high affinity, causing inhibition of the action of angiotensin II on vascular smooth muscle, ultimately leading to a reduction in arterial blood pressure. Recent studies suggest that telmisartan may also have PPAR-gamma agonistic properties that could potentially confer beneficial metabolic effects.
Terazosin is a selective alpha1-antagonist used for treatment of symptoms of benign prostatic hyperplasia (BPH). It also acts to lower blood pressure, so it is a drug of choice for men with hypertension and prostate enlargement. It works by blocking the action of adrenaline on smooth muscle of the bladder and the blood vessel walls.
L-Theanine, also known as L-gamma-glutamylethylamide or N-gamma-ethyl-L-glutamine, is a member of the class of compounds known as glutamine and derivatives. These compounds contain glutamine or a derivative thereof resulting from a reaction of glutamine at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom. L-Theanine is slightly soluble (in water) and a moderately acidic compound (based on its pKa). L-Theanine can be found in saliva. The regulatory status of theanine varies by country. In Japan, L-theanine has been approved for use in all foods, including herb teas, soft drinks, and desserts. Restrictions apply to infant foods. In the United States, the Food and Drug Administration (FDA) considers it to be generally recognized as safe (GRAS) and allows its sale as a dietary supplement. The German Federal Institute for Risk Assessment, an agency of their Federal Ministry of Food and Agriculture, objects to the addition of L-theanine to beverages. The European Food Safety Authority EFSA advised negatively on health claims related to L-theanine and cognitive function, alleviation of psychological stress, maintenance of normal sleep, and reduction of menstrual discomfort. Therefore, health claims for L-theanine are prohibited in the European Union (Wikipedia). L-Theanine is found in mushrooms and is a constituent of tea (Thea sinensis) and of the fungus Imleria badia. L-Theanine has been shown to exhibit neuroprotectant and neuroprotective functions (PMID: 20416364, 20416364).
Theophylline, also known as quibron TSR or uniphyl, belongs to the class of organic compounds known as xanthines. These are purine derivatives with a ketone group conjugated at carbons 2 and 6 of the purine moiety. Theophylline also binds to the adenosine A2B receptor and blocks adenosine mediated bronchoconstriction. Theophylline is a drug which is used for the treatment of the symptoms and reversible airflow obstruction associated with chronic asthma and other chronic lung diseases, such as emphysema and chronic bronchitis. Theophylline is marketed under several brand names such as Theophylline and Theochron, and it is indicated mainly for asthma, bronchospasm, and COPD. Within humans, theophylline participates in a number of enzymatic reactions. In particular, theophylline and formaldehyde can be biosynthesized from caffeine; which is mediated by the enzymes cytochrome P450 1A2, cytochrome P450 3A4, cytochrome P450 2C8, cytochrome P450 2C9, and cytochrome P450 2E1. In addition, theophylline can be converted into 1-methylxanthine and formaldehyde; which is mediated by the enzyme cytochrome P450 1A2. In humans, theophylline is involved in caffeine metabolism. Theophylline is a bitter tasting compound. Outside of the human body, Theophylline is found, on average, in the highest concentration within cocoa beans and tea. Theophylline has also been detected, but not quantified in a few different foods, such as arabica coffee, lemons, and pummelo. This could make theophylline a potential biomarker for the consumption of these foods. Theophylline is a potentially toxic compound.
Thymidine, also known as deoxythymidine or deoxyribosylthymine or thymine deoxyriboside, is a pyrimidine deoxynucleoside. It consists of the nucleobase thymine attached to deoxyribose through a beta N- glycosidic bond. Thymidine also belongs to the class of organic compounds known as pyrimidine 2'-deoxyribonucleosides. Pyrimidine 2'-deoxyribonucleosides are compounds consisting of a pyrimidine linked to a ribose which lacks a hydroxyl group at position 2. Deoxythymidine (or thymidine) is the DNA nucleoside T, which pairs with deoxyadenosine (A) in double-stranded DNA. Therefore, thymidine is essential to all life. Indeed, thymidine exists in all living species, ranging from bacteria to plants to humans. Within humans, thymidine participates in a number of enzymatic reactions. In particular, thymidine can be biosynthesized from 5-thymidylic acid through its interaction with the enzyme cytosolic purine 5'-nucleotidase. In addition, thymidine can be converted into 5-thymidylic acid; which is catalyzed by the enzyme thymidine kinase. Deoxythymidine can be phosphorylated with one, two or three phosphoric acid groups, creating dTMP (deoxythymidine monophosphate), dTDP, or dTTP (for the di- and tri- phosphates, respectively). dTMP can be incorporated into DNA via DNA polymerases. In cell biology, thymidine can be used to synchronize the cells in S phase. Derivatives of thymidine are used in a number of drugs, including Azidothymidine (AZT), which is used in the treatment of HIV infection. AZT inhibits the process of reverse transcription in the human immunodeficiency virus.
Tiagabine is an anti-convulsive medication. It is also used in the treatment for panic disorder as are a few other anticonvulsants. Though the exact mechanism by which tiagabine exerts its effect on the human body is unknown, it does appear to operate as a selective GABA reuptake inhibitor.
Tolterodine is only found in individuals that have used or taken this drug. It is an antimuscarinic drug that is used to treat urinary incontinence. Tolterodine acts on M2 and M3 subtypes of muscarinic receptors.Both tolterodine and its active metabolite, 5-hydroxymethyltolterodine, act as competitive antagonists at muscarinic receptors. This antagonism results in inhibition of bladder contraction, decrease in detrusor pressure, and an incomplete emptying of the bladder.
Topotecan is only found in individuals that have used or taken this drug. It is an antineoplastic agent used to treat ovarian cancer. It works by inhibiting DNA topoisomerases, type I. [PubChem]Topotecan has the same mechanism of action as irinotecan and is believed to exert its cytotoxic effects during the S-phase of DNA synthesis. Topoisomerase I relieves torsional strain in DNA by inducing reversible single strand breaks. Topotecan binds to the topoisomerase I-DNA complex and prevents religation of these single strand breaks. This ternary complex interferes with the moving replication fork, which leads to the induction of replication arrest and lethal double-stranded breaks in DNA. As mammalian cells cannot efficiently repair these double strand breaks, the formation of this ternary complex eventually leads to apoptosis (programmed cell death).Topotecan mimics a DNA base pair and binds at the site of DNA cleavage by intercalating between the upstream (âˆ’1) and downstream (+1) base pairs. Intercalation displaces the downstream DNA, thus preventing religation of the cleaved strand. By specifically binding to the enzymeâ€“substrate complex, Topotecan acts as an uncompetitive inhibitor.
Ketorolac is only found in individuals that have used or taken this drug. It is a pyrrolizine carboxylic acid derivative structurally related to indomethacin. It is an NSAID and is used principally for its analgesic activity (from Martindale The Extra Pharmacopoeia, 31st ed). Ketorolac is a nonsteroidal anti-inflammatory drug (NSAID) chemically related to indomethacin and tolmetin. Ketorolac tromethamine is a racemic mixture of [-]S- and [+]R-enantiomeric forms, with the S-form having analgesic activity. Its antiinflammatory effects are believed to be due to inhibition of both cylooxygenase-1 (COX-1) and cylooxygenase-2 (COX-2) which leads to the inhibition of prostaglandin synthesis leading to decreased formation of precursors of prostaglandins and thromboxanes from arachidonic acid. The resultant reduction in prostaglandin synthesis and activity may be at least partially responsible for many of the adverse, as well as the therapeutic, effects of these medications. Analgesia is probably produced via a peripheral action in which blockade of pain impulse generation results from decreased prostaglandin activity. However, inhibition of the synthesis or actions of other substances that sensitize pain receptors to mechanical or chemical stimulation may also contribute to the analgesic effect. In terms of the ophthalmic applications of ketorolac - ocular administration of ketorolac reduces prostaglandin E2 levels in aqueous humor, secondary to inhibition of prostaglandin biosynthesis.
Torasemide (rINN) or torsemide (USAN) is a pyridine-sulfonylurea type loop diuretic mainly used in the management of edema associated with congestive heart failure. It is also used at low doses for the management of hypertension. It is marketed under the brand name Demadex. [Wikipedia]
trans-Piceid is found in alcoholic beverages. trans-Piceid is present in grapeskins and red wine. It is isolated from Polygonum cuspidatum (Japanese knotweed).Piceid is a stilbenoid glucoside and is a major resveratrol derivative in grape juices
Resveratrol is a polyphenolic phytoalexin. It is also classified as a stilbenoid, a derivate of stilbene, and is produced in plants with the help of the enzyme stilbene synthase. The levels of resveratrol found in food vary greatly. Red wine contains between 0.2 and 5.8 mg/L depending on the grape variety, while white wine has much less. The reason for this difference is that red wine is fermented with grape skins, allowing the wine to absorb the resveratrol, whereas white wine is fermented after the skin has been removed. Resveratrol is also sold as a nutritional supplement. A number of beneficial health effects, such as anti-cancer, antiviral, neuroprotective, anti-aging, anti-inflammatory, and life-prolonging effects have been reported for resveratrol. The fact that resveratrol is found in the skin of red grapes and as a constituent of red wine may explain the "French paradox". This paradox is based on the observation that the incidence of coronary heart disease is relatively low in southern France despite high dietary intake of saturated fats. Resveratrol is thought to achieve these cardioprotective effects by a number of different routes: (1) inhibition of vascular cell adhesion molecule expression; (2) inhibition of vascular smooth muscle cell proliferation; (3) stimulation of endothelial nitric oxide synthase (eNOS) activity; (4) inhibition of platelet aggregation; and (5) inhibition of LDL peroxidation (PMID: 17875315, 14676260, 9678525). Resveratrol is a biomarker for the consumption of grapes and raisins.
Trehalose 6-phosphate is a substrate for Hexokinase (type I) and Tryptase beta-1. Trehalose 6-phosphate has been found to be a microbial metabolite in Escherichia, Mycobacterium and Saccharomyces (UniProt).
Trehalose, also known as mycose, is a 1-alpha (disaccharide) sugar found extensively but not abundantly in nature. It is thought to be implicated in anhydrobiosis - the ability of plants and animals to withstand prolonged periods of desiccation. The sugar is thought to form a gel phase as cells dehydrate, which prevents disruption of internal cell organelles by effectively splinting them in position. Rehydration then allows normal cellular activity to be resumed without the major, generally lethal damage that would normally follow a dehydration/reyhdration cycle. Trehalose is a non-reducing sugar formed from two glucose units joined by a 1-1 alpha bond giving it the name of alpha-D-glucopyranoglucopyranosyl-1,1-alpha-D-glucopyranoside. The bonding makes trehalose very resistant to acid hydrolysis, and therefore stable in solution at high temperatures even under acidic conditions. The bonding also keeps non-reducing sugars in closed-ring form, such that the aldehyde or ketone end-groups do not bind to the lysine or arginine residues of proteins (a process called glycation). The enzyme trehalase, present but not abundant in most people, breaks it into two glucose molecules, which can then be readily absorbed in the gut. Trehalose is an important components of insects circulating fluid. It acts as a storage form of insect circulating fluid and it is important in respiration. Trehalose has also been found to be a metabolite of Burkholderia, Escherichia and Propionibacterium (PMID:12105274; PMID:25479689) (krishikosh.egranth.ac.in/bitstream/1/84382/1/88571%20P-1257.pdf).
Tropate, also known as Tropic acid or alpha-(Hydroxymethyl)phenylacetic acid, is classified as a beta hydroxy acid or a Beta hydroxy acid derivative. Beta hydroxy acids are compounds containing a carboxylic acid substituted with a hydroxyl group on the C3 carbon atom. Tropate is considered to be soluble in water and acidic. Tropate can be synthesized from hydratropic acid and propionic acid. Tropate can be synthesized into tropan-3alpha-yl 3-hydroxy-2-phenylpropanoate
Uridine diphosphategalactose (UDPgal) is a nucleoside diphosphate sugar which can be epimerized into UDPglucose for entry into the mainstream of carbohydrate metabolism. UDPgal is a pivotal compound in the metabolism of galactose. UDPgal is a product of the galactose-l-phosphate uridyl transferase (EC 2.7.7.10) reaction but may also be made from Glucose-l-P, involving uridine diphosphate galactose-4-epimerase (EC 5.1.3.2). UDPgal is the necessary galactosyl donor of galactose in the metabolism to incorporate it into complex oligosaccharides, glycoproteins and glycolipids (galactosides). Defective galactosylation of complex glycoconjugates exists in tissues from galactosemic patients. There is a tendency for galactosemic red cell UDPgal to be in the low normal range with a high uridine diphosphate glucose to UDP-gal ratio. This may reflect an inability of red cell UDPgal-4'-epimerase to maintain a normal ratio and consequently higher levels of UDPgal. In the more complex white blood cells and cultured fibroblasts, the UDPgal content and the uridine diphosphate glucose to UDPgal ratio of galactosemics are normal. Therefore, defective galactosylation observed in galactosemic fibroblasts must result from a defect in the transfer of galactose from UDPgal to these moieties. (PMID: 2122114, 7671968).
Uridine diphosphate glucuronic acid is a nucleoside diphosphate sugar which serves as a source of glucuronic acid for polysaccharide biosynthesis. It may also be epimerized to UDP Iduronic acid, which donates Iduronic acid to polysaccharides. In animals, UDP glucuronic acid is used for formation of many glucosiduronides with various aglycones. The transfer of glucuronic acid from UDP-alpha-D-glucuronic acid onto a terminal galactose residue is done by beta1,3-glucuronosyltransferases, responsible for the completion of the protein-glycosaminoglycan linkage region of proteoglycans and of the HNK1 epitope of glycoproteins and glycolipids. In humans the enzyme galactose-beta-1,3-glucuronosyltransferase I completes the synthesis of the common linker region of glycosaminoglycans (GAGs) by transferring glucuronic acid (GlcA) onto the terminal galactose of the glycopeptide primer of proteoglycans. The GAG chains of proteoglycans regulate major biological processes such as cell proliferation and recognition, extracellular matrix deposition, and morphogenesis. (PMID:16815917).
This compound belongs to the family of Pyrimidine Nucleotide Sugars. These are pyrimidine nucleotides bound to a saccharide derivative through the terminal phosphate group.
Urocanic acid (CAS: 104-98-3) is a breakdown (deamination) product of histidine. In the liver, urocanic acid is an intermediate in the conversion of histidine to glutamic acid, whereas, in the epidermis, it accumulates and may be both a UV protectant and an immunoregulator. Urocanic acid (UA) exists as a trans isomer (t-UA, approximately 30 mg/cm2) in the uppermost layer of the skin (stratum corneum). t-UA is formed as the cells of the second layer of the skin become metabolically inactive. During this process, proteins and membranes degrade, histidine is released, and histidase (histidine ammonia lyase) catalyzes the deamination of histidine to form t-UA. t-UA accumulates in the epidermis until removal by either the monthly skin renewal cycle or sweat. Upon absorption of UV light, the naturally occurring t-UA isomerizes to its cis form, c-UA. Because DNA lesions (e.g., pyrimidine dimers) in the lower epidermis can result from UV-B absorption, initial research proposed that t-UA acted as a natural sunscreen absorbing UV-B in the stratum corneum before the damaging rays could penetrate into lower epidermal zones. Researchers have found that c-UA also suppresses contact hypersensitivity and delayed hypersensitivity, reduces the Langerhans cell count in the epidermis, prolongs skin-graft survival time, and affects natural killer cell activity. (E)-Urocanic acid is found in mushrooms. It has been isolated from Coprinus atramentarius (common ink cap) and Phallus impudicus (common stinkhorn).
cis-11-Octadecenoic acid, also known as (Z)-octadec-11-enoic acid or asclepic acid, belongs to the class of organic compounds known as long-chain fatty acids. These are fatty acids with an aliphatic tail that contains between 13 and 21 carbon atoms. cis-11-Octadecenoic acid is a very hydrophobic molecule, practically insoluble in water, and relatively neutral.
Valaciclovir (INN) or valacyclovir (USAN) is an antiviral drug used in the management of herpes simplex and herpes zoster (shingles). It is a prodrug, being converted in vivo to aciclovir. It is marketed by GlaxoSmithKline under the trade name Valtrex or Zelitrex. [Wikipedia]
Valdecoxib is a prescription drug used in the treatment of osteoarthritis, rheumatoid arthritis, and painful menstruation and menstrual symptoms. It is classified as a nonsteroidal anti-inflammatory drug, or NSAID, and should not be taken by anyone allergic to these types of medications.
Valsartan is an angiotensin-receptor blocker (ARB) that may be used to treat a variety of cardiac conditions including hypertension, diabetic nephropathy and heart failure. Valsartan lowers blood pressure by antagonizing the renin-angiotensin-aldosterone system (RAAS); it competes with angiotensin II for binding to the type-1 angiotensin II receptor (AT1) subtype and prevents the blood pressure increasing effects of angiotensin II. Unlike angiotensin-converting enzyme (ACE) inhibitors, ARBs do not have the adverse effect of dry cough. Valsartan may be used to treat hypertension, isolated systolic hypertension, left ventricular hypertrophy and diabetic nephropathy. It may also be used as an alternative agent for the treatment of heart failure, systolic dysfunction, myocardial infarction and coronary artery disease.
Vanillic acid is a phenolic acid found in some forms of vanilla and many other plant extracts. It is a flavouring and scent agent that produces a pleasant, creamy odour. It is the intermediate product in the two-step bioconversion of ferulic acid to vanillin (J Biotechnol 1996;50(2-3):107-13). Vanillic acid, which is a chlorogenic acid, is an oxidized form of vanillin. It is also an intermediate in the production of vanillin from ferulic acid. Vanillic acid is a metabolic byproduct of caffeic acid and is often found in the urine of humans who have consumed coffee, chocolate, tea, and vanilla-flavoured confectionary. Vanillic acid selectively and specifically inhibits 5'nucleotidase activity (PMID: 16899266). Vanillic acid is a microbial metabolite found in Amycolatopsis, Delftia, and Pseudomonas (PMID: 11152072, 10543794, 11728709, 9579070).
Vanillin, also known as vanillaldehyde or lioxin, belongs to the class of organic compounds known as methoxyphenols. Methoxyphenols are compounds containing a methoxy group attached to the benzene ring of a phenol moiety. It is used by the food industry as well as ethylvanillin. Vanillin exists in all living species, ranging from bacteria to humans. Vanillin is a sweet, chocolate, and creamy tasting compound. Vanillin is found, on average, in the highest concentration within a few different foods, such as corns, ryes, and sherries and in a lower concentration in beers, rums, and oats. Vanillin has also been detected, but not quantified, in several different foods, such as gooseberries, other bread, brazil nuts, shea tree, and ohelo berries. This could make vanillin a potential biomarker for the consumption of these foods. Vanillin is a potentially toxic compound. Synthetic vanillin, instead of natural Vanillin extract, is sometimes used as a flavouring agent in foods, beverages, and pharmaceuticals. Vanillin is the primary component of the extract of the Vanillin bean. Because of the scarcity and expense of natural Vanillin extract, there has long been interest in the synthetic preparation of its predominant component. Artificial Vanillin flavoring is a solution of pure vanillin, usually of synthetic origin. Today, artificial vanillin is made from either guaiacol or from lignin, a constituent of wood which is a byproduct of the paper industry. The first commercial synthesis of vanillin began with the more readily available natural compound eugenol.
Vardenafil (Levitra) is an oral therapy for the treatment of erectile dysfunction. It is a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5). Penile erection is a hemodynamic process initiated by the relaxation of smooth muscle in the corpus cavernosum and its associated arterioles. During sexual stimulation, nitric oxide is released from nerve endings and endothelial cells in the corpus cavernosum. Nitric oxide activates the enzyme guanylate cyclase resulting in increased synthesis of cyclic guanosine monophosphate (cGMP) in the smooth muscle cells of the corpus cavernosum. The cGMP in turn triggers smooth muscle relaxation, allowing increased blood flow into the penis, resulting in erection. The tissue concentration of cGMP is regulated by both the rates of synthesis and degradation via phosphodiesterases (PDEs). The most abundant PDE in the human corpus cavernosum is the cGMPspecific phosphodiesterase type 5 (PDE5); therefore, the inhibition of PDE5 enhances erectile function by increasing the amount of cGMP.
Vincristine is only found in individuals that have used or taken this drug. It is an antitumor alkaloid isolated from Vinca Rosea. (Merck, 11th ed.)The antitumor activity of Vincristine is thought to be due primarily to inhibition of mitosis at metaphase through its interaction with tubulin. Like other vinca alkaloids, Vincristine may also interfere with: 1) amino acid, cyclic AMP, and glutathione metabolism, 2) calmodulin-dependent Ca<sup>2+</sup>-transport ATPase activity, 3) cellular respiration, and 4) nucleic acid and lipid biosynthesis.
Vindesine is only found in individuals that have used or taken this drug. It is a vinblastine derivative with antineoplastic activity against cancer. Major side effects are myelosuppression and neurotoxicity. Vindesine is used extensively in chemotherapy protocols (antineoplastic combined chemotherapy protocols). [PubChem]Vindesine acts by causing the arrest of cells in metaphase mitosis through its inhibition tubulin mitotic funcitoning. The drug is cell-cycle specific for the S phase.
Vitexin, also known as apigenin 8-C-glucoside or 8-glycosylapigenin, belongs to the class of organic compounds known as flavonoid 8-C-glycosides. Flavonoid 8-C-glycosides are compounds containing a carbohydrate moiety which is C-glycosidically linked to 8-position of a 2-phenylchromen-4-one flavonoid backbone. Vitexin is also described as an apigenin flavone glucoside. Vitexin has been found in passion flower, chasteberry, bamboo leaves, millet and Hawthorn. Vitexin has shown a wide range of pharmacological effects, such as antioxidant, anti-cancer, anti-inflammatory, anti-hyperalgesic, and neuroprotective effects (PMID: 27693342). Vitexin has also been shown to directly inhibit thyroid peroxidase and potentially contributes to goiter (PMID: 1696490). It is sometimes called a goitrogen.
Voriconazole (Vfend, Pfizer) is a triazole antifungal medication used to treat serious fungal infections. It is used to treat invasive fungal infections that are generally seen in patients who are immunocompromised. These include invasive candidiasis, invasive aspergillosis, and emerging fungal infections.
Xanthosine, also known as xanthine riboside, belongs to the class of organic compounds known as purine nucleosides. Purine nucleosides are compounds comprising a purine base attached to a ribosyl or deoxyribosyl moiety. Xanthosine is a nucleoside derived from xanthine and ribose. Xanthosine exists in all living species, ranging from bacteria to plants to humans. In plants xanthosine is the biosynthetic precursor to 7-methylxanthosine which is produced by the action of the enzyme known as 7-methylxanthosine synthase. 7-Methylxanthosine in turn is the precursor to theobromine (the active alkaloid in chocolate), which in turn is the precursor to caffeine, the active alkaloid in coffee and tea. Within humans, xanthosine participates in a number of enzymatic reactions. In particular, xanthosine can be biosynthesized from xanthylic acid; which is catalyzed by the enzyme cytosolic purine 5'-nucleotidase. In addition, xanthosine can be converted into xanthine and ribose 1-phosphate; which is mediated by the enzyme purine nucleoside phosphorylase. Xanthosine monophosphate (XMP) is an intermediate in purine metabolism, formed from IMP (inosine monophosphate).
Zafirlukast is an oral leukotriene receptor antagonist (LTRA) for the maintenance treatment of asthma, often used in conjunction with an inhaled steroid and/or long-acting bronchodilator. It is available as a tablet and is usually dosed twice daily. Another leukotriene receptor antagonist is montelukast (Singulair), which is usually taken just once daily. Zafirlukast blocks the action of the cysteinyl leukotrienes on the CysLT1 receptors, thus reducing constriction of the airways, build-up of mucus in the lungs and inflammation of the breathing passages.
Leukotrienes are substances that induce numerous biological effects including augmentation of neutrophil and eosinophil migration, neutrophil and monocyte aggregation, leukocyte adhesion, increased capillary permeability, and smooth muscle contraction. These effects contribute to inflammation, edema, mucus secretion, and bronchoconstriction in the airways of asthmatic patients. Zileuton relieves such symptoms through its selective inhibition of 5-lipoxygenase, the enzyme that catalyzes the formation of leukotrienes from arachidonic acid. Specifically, it inhibits leukotriene LTB4, LTC4, LTD4, and LTE4 formation. Both the R(+) and S(-) enantiomers are pharmacologically active as 5-lipoxygenase inhibitors in in vitro systems.
Zolmitriptan is only found in individuals that have used or taken this drug. It is a synthetic tryptamine derivative and appears as a white powder that is readily soluble in water. [Wikipedia]Zolmitriptan binds with high affinity to human 5-HT<sub>1B</sub> and 5-HT<sub>1D</sub> receptors leading to cranial blood vessel constriction. Current theories proposed to explain the etiology of migraine headache suggest that symptoms are due to local cranial vasodilatation and/or to the release of sensory neuropeptides (vasoactive intestinal peptide, substance P and calcitonin gene-related peptide) through nerve endings in the trigeminal system. The therapeutic activity of zolmitriptan for the treatment of migraine headache can most likely be attributed to the agonist effects at the 5HT1B/1D receptors on intracranial blood vessels (including the arterio-venous anastomoses) and sensory nerves of the trigeminal system which result in cranial vessel constriction and inhibition of pro-inflammatory neuropeptide release.