Inhibitory effects of tea extracts and (-)-epigallocatechin gallate on DNA synthesis and proliferation of hepatoma and erythroleukemia cells.

Polyphenols extracted from green or black tea with ethyl acetate were strongly inhibitory for DNA synthesis in HTC rat hepatoma cells and DS19 mouse erythroleukemia cells at concentrations of 0.1-0.2 mg/ml. There was less inhibition with a subsequent black tea fraction extracted with butanol and with the residual water-soluble fraction. Although cell proliferation was inhibited by (-)-epigallocatechin gallate and the tea extracts, there were only marginal effects on differentiation of DS19 cells as judged by hemoglobin synthesis.