Anti-proliferative effect and cell cycle arrest induced by saponins extracted from tea (Camellia sinensis) flower in human ovarian cancer cells.

Tea (Camellia sinensis) flower saponins (TFS) have various biological properties. However, the anti-cancer effects of TFS have not been investigated in any detail. Here, we evaluated the anti-cancer effects of TFS using human ovarian cancer cell lines. TFS (1.5 μg/ml) produced significant antiproliferative effects against A2780/CP70 and OVCAR-3 cells by inducing p53-dependent apoptosis and S phase arrest. Further study showed that TFS decreased mitochondrial membrane potential, activated Caspase-3/7, Caspase-8 and Caspase-9 activities, and that the p53 inhibitor PFT-α reversed the TFS-induced cell growth inhibition and apoptosis. In addition, TFS inhibited the expression of Cdc25A, Cdk2, and CyclinD1 and upregulated Cyclin E and Cyclin A, suggesting that the Cdc25A-Cdk2-Cyclin E/A pathway was involved in TFS-induced S phase arrest. Furthermore, the S phase arrest was associated with a Chk2-Cdc25A DNA damage response. These results demonstrated that TFS has promising potential serving as functional food components for prevention of ovarian cancer.