Abstract: ObjectiveTo investigate the effect of chloroform extracts (CE) of leaves from Crinum asiaticum on proliferation and apoptosis of non-small cell lung cancer(NSCLC) NCI-H460 cells . Methods The activity of cell growth inhibition of NCI-H460 cells was measured by MTT assay. Morphological changes of cell nuclei were observed by Hoechst 33258 staining. The expression levels of Bcl-2 and Bax proteins were examined by immunocytochemistry staining. Flow cytometry was performed to measure the cell cycle. ResultsCE displayed growth inhibitory activity against NCI-H460 cells with IC50 values of 36.22 ±3.04, 41.21±2.50 and 62.55±3.47 mg/L for 24,48 and 72 h, respectively. The effect enhanced with an increase in the concentration of CE. The condensed chromatin, nuclear fragmentation and a large number of apoptotic bodies was observed by Hoechst 33258 staining. The percentage of apoptosis in NCI-H460 cells increased after treated with CE, compared with control. The expression level of Bax protein in NCI-H460 cells cultured with CE were higher than that of control, and the expression level of Bcl-2 protein in NCI-H460 cells dealt with CE were lower than that of control. The arrest of NCI-H460 cells in G1/S phases was induced by CE. ConclusionIn vitro CE significantly inhibited the growth of NCI-H460 cells. Antitumor mechanism of NCI-H460 cells may be associated with the changes of cell cycle and cell apoptosis.