Vitamin C

Mark Levine, Arie Katz, Sebastian J. Padayatty, Yaohui Wang, Peter Eck, Oran Kwon, Shenglin Chen, Jee Hyuk Lee

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

1 Scopus citations


Vitamin C is an electron donor, and this property accounts for its known and postulated functions. As an antioxidant, or reducing agent, the vitamin sequentially donates two electrons from the C2-C3 double bond. The first intermediate, formed by the loss of one electron, is the unstable free radical semidehydroascorbic acid. This intermediate is relatively unreactive and does not interact with other compounds to form potentially harmful free radicals, and can be reversibly reduced to ascorbate. Semidehydroascorbic acid undergoes further oxidation to form the more stable product dehydroascorbic acid (DHA) (Fig. 1), which can be reduced back to ascorbate by glutathione or by three distinct enzymatic reduction reactions.[2,3] If not reduced, DHA undergoes ring rupture and is irreversibly hydrolyzed to 2,3-diketogulonic acid. The latter is metabolized to xylose, xylonate, lyxonate, and oxalate, which is a clinically significant end product of vitamin C metabolism.

Original languageEnglish
Title of host publicationEncyclopedia of Dietary Supplements
PublisherCRC Press
Number of pages11
ISBN (Electronic)9781482204056
ISBN (Print)0824755049, 9780824755041
StatePublished - 1 Jan 2004

Bibliographical note

Publisher Copyright:
© 2005 by Marcel Dekker. All rights reserved.


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