Protective effect of extracts of Mesona procumbens Hemsl. on DNA damage inhuman lymphocytes exposed to hydrogen peroxide and UV irradiation

In the present study, the protective effect of mater extracts from Hsian-ts ao (WEHT) on DNA damage in human lymphocytes induced by W-C and/or H2O2 was evaluated using single-cell electrophoresis (comet assay). No toxicity was found in WEHT towards human lymphocytes. WEHT did not cause DNA damage at loser concentrations of 0.05 and 0.1 mg/ml, while it did cause slight DNA d amage at a concentration of 0.5-2.5 mg/ml when compared with the control gr oup. When WEHT was mixed with H2O2 for reaction, it exhibited a slight inhi bitory effect on DNA damage induced by H2O2 Moreover, when WEHT and lymphoc ytes were irradiated by UV-C and then incubated for 35 min, the DNA damage decreased with an increase of the concentration of WEHT. Thus, WEHT could r educe UV-C-induced DNA damage, and WEHT had a more protective effect on UV- C than on H2O2-induced DNA damage. The protective effect of WEHT on DNA dam age might be due to the fact that it contains polyphenol compounds and/or o ther active components. (C) 2000 Elsevier Science Ltd. All rights reserved.