ObjectiveTo investigate the mechanism of lignans-1inhibiting the proliferation of human gastric cancer cell line SGC-7901. MethodsThe morphological changes of the cells were observed by the inverted phase contrast microscope. The cell surviving ratio was determined by methylthiazoly tetrazolium (MTT) assay after lignans-1 added to the cells at different concentrations on human gastric cancer SGC-7901 cell line in vitro, and half maximal (50%) inhibitory concentration (IC50) values were calculated. The cell cycle phase distribution and apoptosis were measured by flow cytometry. The expressions of apoptosis associated proteins of Caspase3, Bcl-2 and Bax were determined by Western blot. ResultsMorphological examination showed that lignans-1 could destroy the SGC-7901 cells with the increasing concentration of lignans-1. The inhibitory effect of lignans-1 on SGC-7901 cell was associated with time-and dose-dependent manner at the different concentration (2.5-20 μg/mL), P < 0.05. The IC50 of lignans-1 on the SGC-7901 cells was 4.19 μg/mL. The rate of the apoptosis cells and G2/M phase cells raised significantly after 48 hours' treatment with lignans-1, as same as the expression of Caspase3 and Bax (P < 0.05). G0/G1 phase cells and Bcl-2 decreased significantly with the increasing concentration of lignans-1 (P < 0.05). ConclusionsThe lignans-1 could inhibit the proliferation of SGC-7901 cells and induce apoptosis by arresting cells at G2/M phase in vitro. The mechanism is associated with activation of Caspase3 and Bax and inhibition of Bcl-2.