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Changes of Constituents and Activity to Apoptosis and Cell Cycle During Fermentation of Tea
Key Laboratory for Molecular Enzymology & Engineering, the Ministry of Education, Jilin University, Changchun 130012, China
College of Life Science, Jilin University, Changchun 130012, China
Yunnan Research Centre for Advance Tea Processing, Yunnan Agricultural University, Kunming 650201, China
* Authors to whom correspondence should be addressed.
Received: 26 January 2011; in revised form: 24 February 2011 / Accepted: 28 February 2011 / Published: 10 March 2011
Abstract: Tea is believed to be beneficial for health, and the effects of the fermentation process on its contributions to apoptosis and cell cycle arrest of gastric cancer cells have not been completely investigated. In this study, the chemical components in green tea, black tea and pu-erh tea aqueous extracts were analyzed and compared. 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. Hence, a treatment of tea aqueous extract and the components, which are emerging as promising anticancer agents, were pursued to determine whether this treatment could lead to enhance apoptosis and cell cycle arrest. In the human gastric cancer cell line SGC-7901, the cell viability and flow cytometry analysis for apoptotic cells indicated effects in a dose-dependent inhibition manner for the three tea treatment groups. The apoptosis rates were found to be elevated after 48 h of treatment with 31.2, 125, and 500 μg/mL of green tea extract, the higher catechins content may be involved in the mechanism. Cell cycle was arrested in S phase in the fermented black tea and pu-erh tea, and the populations were significantly decreased in G2/M phases, possibly due to the oxidation of tea polyphenols, which causes an increase of theabrownins. CCC-HEL-1 normal cells were not sensitive to tea extract. These findings suggest that the fermentation process causes changes of the compounds which might be involved in the changes of cell proliferation inhibition, apoptosis induction and cell cycle arrest.
Keywords: tea; catechins; theabrownins; caffeine; apoptosis; cell cycle
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MDPI and ACS Style
Zhao, H.; Zhang, M.; Zhao, L.; Ge, Y.-K.; Sheng, J.; Shi, W. Changes of Constituents and Activity to Apoptosis and Cell Cycle During Fermentation of Tea. Int. J. Mol. Sci. 2011, 12, 1862-1875.
Zhao H, Zhang M, Zhao L, Ge Y-K, Sheng J, Shi W. Changes of Constituents and Activity to Apoptosis and Cell Cycle During Fermentation of Tea. International Journal of Molecular Sciences. 2011; 12(3):1862-1875.
Zhao, Hang; Zhang, Min; Zhao, Lu; Ge, Ya-kun; Sheng, Jun; Shi, Wei. 2011. "Changes of Constituents and Activity to Apoptosis and Cell Cycle During Fermentation of Tea." Int. J. Mol. Sci. 12, no. 3: 1862-1875.