OBJECTIVETo investigate the inhibition of three C2 steroidal saponins from Cynanchum auriculatum on the cell growth and cell cycle of human lung cancer A549 cells.

METHODA549 cells were exposed to three C21 steroidal saponins of different concentrations (5, 10, 20, 40, 60, 80, 100 micromol L(-1)) for 48 hours. After 48 h, MTT assay was used to evaluate the inhibiting effects of three C21 steroidal saponins on the proliferation of the A549 cells. Exponential growth phase A549 cells were treated with 47, 34, 60 micromol x L(-1) of three C21 steroidal saponins respectively for 12, 24, 48 h, then the changes of cell cycle were analyzed by flow cytometry.

RESULTThe three C21 steroidal saponins could inhibit the growth of A549 cells in dose-dependent manner and IC50 is 46. 07 mol x L(-1), 33.02 mol x L(-1), 59.92 mol x L(-1) respectively. The cell cycle analysis showed that wilfoside C1N and wilfoside C3N increased the percentage of G0/G1 phase cells and decreased G2/M and S-phase cells while the proportion of cells in S-phase was lower and in G2/M phase the proportion was higher than control when the cells were cultivated with wilfoside K1N (P < 0.05, P < 0.01).

CONCLUSIONThree C21 steroidal saponins could inhibit the proliferation of A549 cells in dose-dependent manner and the mechanism may be related to its arresting the cell cycle.