Dehydroascorbic acid (DHA) is an oxidized form of ascorbic acid (vitamin C). It is actively imported into the endoplasmic reticulum of cells via glucose transporters. It is trapped therein by reduction back to ascorbate by glutathione and other thiols. Dehydroascorbic acid, also known as L-dehydroascorbate or DHAA, belongs to the class of organic compounds known as gamma butyrolactones. Gamma butyrolactones are compounds containing a gamma butyrolactone moiety, which consists of an aliphatic five-member ring with four carbon atoms, one oxygen atom, and bears a ketone group on the carbon adjacent to the oxygen atom. Dehydroascorbic acid has similar biological activity as ascorbic acid. Currently dehydroascorbic acid is an experimental drug with no known approved indications. Dehydroascorbic acid may be a unique E. coli metabolite. Norepinephrine and dehydroascorbic acid can be biosynthesized from dopamine and ascorbic acid through its interaction with the enzyme dopamine beta-hydroxylase. In humans, dehydroascorbic acid is involved in the metabolic disorder called tyrosinemia type I. Concerning dehydroascorbic acid's antiviral effect against herpes simplex virus type 1, it is suggested that dehydroascorbic acid acts after replication of viral DNA and prevents the assembly of progeny virus particles. This is important because one study has found that after an ischemic stroke, dehydroascorbic acid has neuroprotective effects by reducing infarct volume, neurological deficits, and mortality. This reaction is reversible, but dehydroascorbic acid can instead undergo irreversible hydrolysis to 2,3-diketogulonic acid. In addition, unlike ascorbic Dehydroascorbic acid acid can cross the blood brain barrier and is then converted to ascorbic acid to enable retention in the brain. Dehydroascorbic acid is made from the oxidation of ascorbic acid. The exact mechanism of action is still being investigated, but some have been elucidated. Both compounds have been shown to have antiviral effects against herpes simplex virus type 1, influenza virus type A and poliovirus type 1 with dehydroascorbic acid having the stronger effect. In the body, both dehydroascorbic acid and ascorbic acid have similar biological activity as antivirals but dehydroascorbic acid also has neuroprotective effects. Even though dehydroascorbic acid and ascorbic acid have similar effects, their mechanism of action seems to be different.