Prodrug not its intended target. This reduces adverse or unintended effects of a drug, especially important in treatments like chemotherapy, which can have severe unintended and undesirable side effects. Many herbal extracts historically used in medicine contain glycosides (sugar derivatives) of the active agent, which are hydrolyzed in the intestines to release the active and more bioavailable aglycone. For example, salicin is a β-D-glucopyranoside that is cleaved by esterases to release salicylic acid. Aspirin, acetylsalicylic acid, first made by Felix Hoffmann at Bayer in 1897, is a synthetic prodrug of salicylic acid. However, in other cases, such as codeine and morphine,
Homogentisic acid Homogentisic acid Homogentisic acid (2,5-dihydroxyphenylacetic acid) is a phenolic acid usually found in "Arbutus unedo" (strawberry-tree) honey. It is also present in the bacterial plant pathogen "Xanthomonas campestris pv. phaseoli" as well as in the yeast "Yarrowia lipolytica" where it is associated with the production of brown pigments. It is oxidatively dimerised to form hipposudoric acid, one of the main constituents of the 'blood sweat' of hippopotamuses. It is less commonly known as melanic acid, the name chosen by William Prout. Accumulation of excess homogentisic acid and its oxide, named alkapton, is a result of the failure of the enzyme