Viniferin formation by COX-1: Evidence for radical intermediates during co-oxidation of resveratrol

Lawrence M. Szewczuk, Hwa Lee Seon, Ian A. Blair, Trevor M. Penning

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)


Resveratrol (1) is a polyphenolic natural product, which functions as both a mechanism-based inactivator and a co-reductant of the COX-1 peroxidase. These functions are mediated through different moieties on the molecule, namely, the m-hydroquinone moiety (mechanism-based inactivator) and the phenol moiety (co-reductant). Implicit in this bifunctionality is the notion that resveratrol is oxidized at the peroxidase active site of COX-1, resulting in the formation of two hypothetical radical species. Oxidation of the m-hydroquinone moiety can generate a hypothetical m-semiquinone radical, which is unstabilized and leads to irreversible enzyme inactivation. Oxidation of the phenol moiety can generate a hypothetical phenoxy radical, which is stabilized and leads to co-reduction during peroxidase catalysis. These two radicals have been trapped as the resveratrol dimers, cis-ε-viniferin (4, trapped m-semiquinone radical) and trans-δ-viniferin (5, trapped phenoxy radical), and identified by liquid chromatography (LC), absorbance spectroscopy, and LC/tandem mass spectrometry (MSn) methods. Methoxy-resveratrol analogues, in which either the m-hydroquinone or the phenol moiety were protected as methyl ethers, were used to confirm the proposed mechanism of viniferin production by COX-1.

Original languageEnglish
Pages (from-to)36-42
Number of pages7
JournalJournal of Natural Products
Issue number1
Publication statusPublished - 2005 Jan
Externally publishedYes

ASJC Scopus subject areas

  • Analytical Chemistry
  • Molecular Medicine
  • Pharmacology
  • Pharmaceutical Science
  • Drug Discovery
  • Complementary and alternative medicine
  • Organic Chemistry


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