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Changes of constituents and activity to apoptosis and cell cycle during fermentation of tea.

Zhao H, Zhang M, Zhao L, Ge YK, Sheng J, Shi W - Int J Mol Sci (2011)

Bottom Line: In this study, the chemical components in green tea, black tea and pu-erh tea aqueous extracts were analyzed and compared.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.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory for Molecular Enzymology & Engineering, the Ministry of Education, Jilin University, Changchun 130012, China; E-Mails: zhzky@163.com (H.Z.); zhangmin2584652@yahoo.com.cn (M.Z.); zhaolu_1987@126.com (L.Z.); yakunge@126.com (Y.-K.G.).

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.

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Flow cytometric analysis of cell apoptosis induced by treatment for 48 h in SGC-7901 and CCC-HEL-1 cells. (A) Apoptotic cells after treatment with three tea extracts at concentrations of 31.2, 125 and 500 μg/mL in SCG-7901 cells and 500 μg/mL in CCC-HEL-1 cells; (B) Apoptotic cells after treatment with tea constituents at the concentrations of 10, 50 and 250 μg/mL in SCG-7901 cells and 250 μg/mL in CCC-HEL-1 cells.
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f3-ijms-12-01862: Flow cytometric analysis of cell apoptosis induced by treatment for 48 h in SGC-7901 and CCC-HEL-1 cells. (A) Apoptotic cells after treatment with three tea extracts at concentrations of 31.2, 125 and 500 μg/mL in SCG-7901 cells and 500 μg/mL in CCC-HEL-1 cells; (B) Apoptotic cells after treatment with tea constituents at the concentrations of 10, 50 and 250 μg/mL in SCG-7901 cells and 250 μg/mL in CCC-HEL-1 cells.

Mentions: To investigate whether apoptosis contributed to cell growth inhibition by tea extracts and their components, an assessment of apoptosis rate was observed using flow cytometry. Both the early stage of apoptosis (lower-right) and the late stage of apoptosis (upper-right) in SGC-7901 and CCC-HEL-1 cells were investigated. We examined the concentration-dependence of the samples on apoptosis in SGC-7901 cells. As demonstrated, treatment with tea extracts for 48 h induced early and late stage apoptosis (Figure 3A). Results showed that the percentage of early apoptosis increased to 3.48 ± 0.42%, 2.47 ± 0.45% and 1.93 ± 0.79% compared with 1.75 ± 0.36% in control cells by 31.2 μg/mL green tea, black tea and pu-erh tea, respectively. Treatment with 500 μg/mL increased the percentage of early apoptosis to 45.93 ± 3.25%, 35.64 ± 3.17 and 27.65 ± 2.19%, respectively. The data indicated that the three kinds of tea extract could induce early apoptosis, and the percentage induced in the green tea extract groups was higher than the black tea group, with the lowest rate in pu-erh tea groups at the same concentration .The fermentation process causes changes of the compounds, which may result in reducing the apoptosis of SGC-7901 cells. Early apoptosis was induced by the addition of catechins in the SGC-7901 cell line, rising from 3.91 ± 0.32% to 55.59 ± 5.02% (Figure 3B). The combination of catechins also increased late apoptosis, but insignificantly greater than early apoptosis. A significant reduction in early apoptotic activity was observed with theabrownins when compared to the catechins at the same concentration. Late apoptosis was significantly observed by the addition of caffeine, and no significant changes in late apoptosis were observed with different concentrations.


Changes of constituents and activity to apoptosis and cell cycle during fermentation of tea.

Zhao H, Zhang M, Zhao L, Ge YK, Sheng J, Shi W - Int J Mol Sci (2011)

Flow cytometric analysis of cell apoptosis induced by treatment for 48 h in SGC-7901 and CCC-HEL-1 cells. (A) Apoptotic cells after treatment with three tea extracts at concentrations of 31.2, 125 and 500 μg/mL in SCG-7901 cells and 500 μg/mL in CCC-HEL-1 cells; (B) Apoptotic cells after treatment with tea constituents at the concentrations of 10, 50 and 250 μg/mL in SCG-7901 cells and 250 μg/mL in CCC-HEL-1 cells.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3111638&req=5

f3-ijms-12-01862: Flow cytometric analysis of cell apoptosis induced by treatment for 48 h in SGC-7901 and CCC-HEL-1 cells. (A) Apoptotic cells after treatment with three tea extracts at concentrations of 31.2, 125 and 500 μg/mL in SCG-7901 cells and 500 μg/mL in CCC-HEL-1 cells; (B) Apoptotic cells after treatment with tea constituents at the concentrations of 10, 50 and 250 μg/mL in SCG-7901 cells and 250 μg/mL in CCC-HEL-1 cells.
Mentions: To investigate whether apoptosis contributed to cell growth inhibition by tea extracts and their components, an assessment of apoptosis rate was observed using flow cytometry. Both the early stage of apoptosis (lower-right) and the late stage of apoptosis (upper-right) in SGC-7901 and CCC-HEL-1 cells were investigated. We examined the concentration-dependence of the samples on apoptosis in SGC-7901 cells. As demonstrated, treatment with tea extracts for 48 h induced early and late stage apoptosis (Figure 3A). Results showed that the percentage of early apoptosis increased to 3.48 ± 0.42%, 2.47 ± 0.45% and 1.93 ± 0.79% compared with 1.75 ± 0.36% in control cells by 31.2 μg/mL green tea, black tea and pu-erh tea, respectively. Treatment with 500 μg/mL increased the percentage of early apoptosis to 45.93 ± 3.25%, 35.64 ± 3.17 and 27.65 ± 2.19%, respectively. The data indicated that the three kinds of tea extract could induce early apoptosis, and the percentage induced in the green tea extract groups was higher than the black tea group, with the lowest rate in pu-erh tea groups at the same concentration .The fermentation process causes changes of the compounds, which may result in reducing the apoptosis of SGC-7901 cells. Early apoptosis was induced by the addition of catechins in the SGC-7901 cell line, rising from 3.91 ± 0.32% to 55.59 ± 5.02% (Figure 3B). The combination of catechins also increased late apoptosis, but insignificantly greater than early apoptosis. A significant reduction in early apoptotic activity was observed with theabrownins when compared to the catechins at the same concentration. Late apoptosis was significantly observed by the addition of caffeine, and no significant changes in late apoptosis were observed with different concentrations.

Bottom Line: In this study, the chemical components in green tea, black tea and pu-erh tea aqueous extracts were analyzed and compared.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.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory for Molecular Enzymology & Engineering, the Ministry of Education, Jilin University, Changchun 130012, China; E-Mails: zhzky@163.com (H.Z.); zhangmin2584652@yahoo.com.cn (M.Z.); zhaolu_1987@126.com (L.Z.); yakunge@126.com (Y.-K.G.).

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.

Show MeSH
Related in: MedlinePlus