Study of Radioprotective Effect of Green Tea against Gamma Irradiation Using Micronucleus Assay on Binucleated Human Lymphocytes

OBJECTIVES The aim of this study was to investigate the radioprotective effect of green tea against genotoxicity induced by gamma irradiation in cultured blood lymphocytes from 5 human volunteers. MATERIALS AND METHODS Peripheral blood samples were collected from volunteers before and 1, 3 and 5 hr after drinking a decoction 4 g green tea in 280 ml boiling water for 5 constitutive days with the same quantity. At each time point, the whole blood samples were exposed to 200 cGy of (60) Co gamma irradiation and then were cultured with mitogenic stimulation to determine the chromosomal aberration in micronucleus assay on cytokinesis-blocked binucleated cells. RESULTS As expected, for each volunteer, the results showed a significant increase in the incidence of micronuclei after exposure to gamma irradiation as compared to non-irradiated control samples. Only lymphocytes blood sample collected 3 hr after drinking green tea exhibited a significant decrease in incidence of micronuclei compared to non-treated irradiated samples. CONCLUSION These results suggest the radioprotective ability of green tea against ionizing radiation in human lymphocytes, at specified time after consumptior.