title: Dual function of (--)-epigallocatechin gallate (EGCG) in healthy human lymphocytes.
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).
authors.affiliation: Department of Social and, Osaka University Graduated School of Medicine, Osaka 565-0871, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Kanadzu
authors.forename: Yuquan
authors.initials: Y
authors.lastname: Lu
authors.forename: Kanehisa
authors.initials: K
authors.lastname: Morimoto
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000494:pharmacology*; D001761:Bleomycin / Q000494:pharmacology; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D004249:DNA Damage / Q000187:drug effects; D016166:Free Radical Scavengers / Q000494:pharmacology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008214:Lymphocytes / Q000187:drug effects*; D008297:Male; D016877:Oxidants / Q000494:pharmacology*; D010084:Oxidation-Reduction
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D016877:Oxidants; D001761:Bleomycin; D002392:Catechin; D006861:Hydrogen Peroxide; C045651:epigallocatechin gallate