Suppressing Effect of Tannic Acid on UV and Chemically Induced Chromosome Aberrations in Cultured Mammalian Cells

UV-induced structural chromosome aberrations were suppressed by post-treatment with tannic acid (w-galoyl gallic acid) in cultured Chinese hamster ovary cells. A significant decrease in the frequencies of chromosome aberrations in the presence of tannic acid was observed in cells treated with mitomycin C or methylmethanesulfonate but not with X-rays or bleomycin. The effects of tannic acid were dependent on the DNA pre-replicational Gl phase of the cell cycle. Furthermore, tannic acid enhanced the liquid-holding effect on UV-irradiated cells at Gl phase. On the other hand, the number of surviving UV-irradiated cells increased in the presence of tannic acid. These results suggest the possibility of promotion by tannic acid of an excision repair system of mammalian cells.