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Tea components effect on apoptosis and cell cycle of gastric cancer cell

Tea is popular widespread because of its possible beneficial health effects. Generally, tea can be classified according to the production method as unfermented tea (green tea), fully fermented tea (black tea) and post-fermented tea  (pu-erh tea). The chemical components in these three kinds of tea extracts were different. The polysaccharide and caffeine levels were substantially higher  in the fermented black tea and pu-erh tea, while the polyphenol level was higher in the unfermented green tea. This differentiation has distinct effect on apoptosis and cell cycle arrest.

The results showed that catechins, which is the main tea phenolic compounds, could induce early apoptosis of gastric cancer cell lines SGC-7901 higher, and during the fermentation process, the content of phenolic compounds reduced. Cell cycle results showed that the proportion of G2/M phase cells decreased with the fermentation process, which may be due to the oxidation of tea polyphenols, and increase of theabrownins. In addition, the results also showed that tea extract and their constituents have lower cytotoxicity to normal CCC-HEL-1 cells. Cell cycle was not affected with the high concentration treatment. These results suggest that tea extract and their constituents could be a candidate agent for the therapy of gastric cancer.

Figure 1 Flow cytometric analysis of cell apoptosis induced by treatment for 48 h in  SGC-7901 and CCC-HEL-1 cells.

Figure 2 Cell cycle analysis of SGC-7901 and CCC-HEL-1 cells after treatment with three kinds of tea extract and their main constituents.

Reference: Hang Zhao, Min Zhang, Lu Zhao, Ya-kun Ge, Jun Sheng and Wei Shi. Changes of Constituents and Activity to Apoptosis and Cell Cycle During Fermentation of Tea. Int. J. Mol. Sci. 2011 12: 1862-1875; doi:10.3390/ijms12031862