Redox properties of tea polyphenols and related biological activities

Shengmin Sang, Zhe Hou, Joshua D. Lambert, Chung S. Yang

Research output: Contribution to journalReview articlepeer-review

114 Scopus citations


Plant polyphenolic compounds are known to be strong antioxidants. Because oxidative stress is believed to contribute to many acute and chronic diseases, these polyphenols have been postulated to have many beneficial health effects, such as the prevention of cancer and cardiovascular diseases. Indeed, some of these beneficial effects have been demonstrated in animal models and in some, but not all, epidemiological studies. Nevertheless, only some of these activities have been demonstrated to be associated with the antioxidative activities of polyphenols. In studies with cell lines in culture, some of the observed activities may be due to superoxide and hydrogen peroxide produced during the autooxidation of polyphenols. Such pro-oxidation-dependent reactions may not happen in tissues where the oxygen partial pressure is much lower than that in cell culture medium. This review will use the well-studied tea polyphenol, (-)-epigallocatechin-3-gallate, as an example to illustrate the redox properties of polyphenols and their influence on signaling pathways related to anti-cancer activities. Existing data suggest, however, that most of the relevant mechanisms of cancer prevention by tea polyphenols are not related to their redox properties, but are due to the direct binding of the polyphenol to target molecules, including the inhibition of selected protein kinases, matrix metalloproteinases, and DNA methyltransferases.

Original languageEnglish (US)
Pages (from-to)1704-1714
Number of pages11
JournalAntioxidants and Redox Signaling
Issue number11-12
StatePublished - Nov 2005

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Physiology
  • Molecular Biology
  • Clinical Biochemistry
  • Cell Biology


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