Kanadzu M, Lu Y, Morimoto K. Dual function of (−)-epigallocatechin gallate (EGCG) in healthy human lymphocytes.
Cancer Lett 2006;
241:250-5. [PMID:
16303244 DOI:
10.1016/j.canlet.2005.10.021]
[Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2005] [Revised: 10/13/2005] [Accepted: 10/18/2005] [Indexed: 12/14/2022]
Abstract
(-)-Epigallocatechin gallate (EGCG), a catechin polyphenol component, is the main ingredient of green tea extract. Recently, increasing attention has been given to its anti-oxidant effects. However, several studies reported the oxidative effects of EGCG, suggesting that EGCG had a dual function of anti-oxidant and pro-oxidant potentials. In this study, we examined the influences of EGCG on healthy human whole blood lymphocytes and purified blood lymphocytes using a single-cell gel electrophoresis (SCG) assay. The results showed that EGCG suppressed the DNA strand breakage in whole blood lymphocytes at concentrations from 10(-8) to 10(-5)M, while it induced DNA strand breakage at concentration of 10(-3)M. Furthermore, EGCG at concentrations of 10(-6)-10(-4)M suppressed the DNA strand breakage induced by bleomycin (BLM) and H(2)O(2) in whole blood lymphocytes. In the same range of 10(-6)-10(-4)M, EGCG increased DNA strand breakage in purified blood lymphocytes, but suppressed the DNA breakage induced by BLM at lower concentrations from 10(-8) to10(-7)M. From these findings, we propose that EGCG might have a dual function of anti-oxidant and pro-oxidant in healthy human lymphocytes, which would involved in its inhibitory effects against DNA strand breakage induced by BLM and H(2)O(2).
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