Effect of green tea extract on DNA repair and oxidative damage due to H2O2 in Jurkat T cells

Green tea is considered as an aid to good health since it should increase the antioxidants defence system of the body against radical damage. The aim of this study was to investigate, in Jurkat cells, the protective effect of green tea extract (GTE) supplementation (10 mg/L, corresponding to 15 mumol/L EGCg, 24 h) against oxidative DNA damage induced by different concentrations of hydrogen peroxide (from 10 to 200 mumol/L H2O2 for 15 min). The DNA damage, evaluated by the Comet assay, was dose dependent, however it reached a plateau at 75 mumol/L of H2O2 without any protective effect exerted by GTE. The DNA repair process, completed within 2 hours, was unaffected by supplementation. These results seem to suggest that GTE supplementation, is not able to protect Jurkat cells against H2O2 induced DNA damage, at least under the conditions used in this study. (C) 2002 Elsevier Science Inc. All rights reserved.