Effects of tea extracts of different fermentations on proliferation of colorectal cancer cell line HCT116

There is no conclusion if tea polyphenols have effect on colorectal cancer, and no report about the effect of tea polyphenols on colorectal cancer cells in different degree of fermentation (unfermented/semi-fermented/ full-fermented). Three kinds of tea polyphenol extracts of Huangshan Maofeng, Robe Tea and Keemun Black Tea were selected in this study. The effects of tea polyphenol extracts on cell growth were detected by MTS method. Cell morphological changes of colorectal cancer cell HCT116 were observed by inverted microscope after treated with three tea polyphenol extracts separately. The MTS data reflected that the proliferation of HCT116 cells could be inhibited in different degrees by these tea polyphenol extracts from three kinds of tea (P<0.05). And the IC50 of tea polyphenol extracts to HCT116 were different according to the different fermentation degree of the tea. The morphology of the cells which were separately treated by the tea polyphenol extracts with the doses of 15, 35 μg/mL were observed. The results showed that HCT116 were undergoing different degree of apoptosis morphological changes compared with the control after treated by three kinds of tea polyphenol extracts for 72 h. The tea polyphenol extracts of Huangshan Maofeng, Robe Tea and Keemun Black Tea have inhibitory effects on HCT116 and induce the apoptosis of HCT116. The inhibition effects to HCT116 by the tea polyphenol extracts from tea are significantly different according to the different fermentation degree.