Cytotoxic and apoptosis-inducing properties of a C21-steroidal glycoside isolated from the roots of Cynanchum auriculatum

The present study aimed to investigate the anti-cancer effect of a C 21 -steroidal glycoside (CG) isolated from the roots of Cynanchum auriculatum . CG was able to inhibit the growth of human cancer cells (SGC-7901 cells) in a concentration and time-dependent manner in vitro . SGC-7901 cells exposed to CG (10.8 and 21.6 μ M) exhibited typical morphological apoptosis characteristics, such as nuclear-chromatin condensation and apoptotic body formation. Flow cytometric analysis showed that after treatment with CG at 10.8 and 21.6 μ M for 24 h, the percentage of apoptotic cells increased to 30.4 and 43.2%, respectively, while the number of cells in the G 0 /G 1 , S and G 2 /M phases of the cell cycle decreased (P<0.05). Furthermore, treatment with CG at a concentration of 21.6 μ M for 24 h significantly increased the expression of caspase-3 and the activity of caspase-3 was increased ∼3-fold in SGC-7901 cells. These results suggest that CG is the active anticancer component of the total C 21 -glycosides of the roots of Cynanchum auriculatum which is able to inhibit the growth of cancer cells and induce cancer cell apoptosis through caspase-3-dependent pathways.