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Dual function of (--)-epigallocatechin gallate (EGCG) in healthy human lymphocytes.

Cancer letters (2005-11-24)
Masaki Kanadzu, Yuquan Lu, Kanehisa Morimoto
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).

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
(−)-Epigallocatechin gallate, ≥95%
Sigma-Aldrich
(−)-Epigallocatechin gallate, ≥80% (HPLC), from green tea
Supelco
(−)-Epigallocatechin gallate, analytical standard
Epigallocatechin gallate, primary reference standard