Objective To discuss on mechanism of the killing and apoptosis inducing effect induced by total alkaloid in the CSS(Capparis spinosa L.saponin,CSS)on human hepatocarcinoma cell Line HepG-2.Methods The killing effect of the CSS on human hepatocarcinoma cell Line HepG-2 was observed by MTT method.Morphological observation of the HepG-2 cells was completed by fluorescence microscope.This test was signed to observe the changes of the cell cycle of HepG-2 cells affected by the CSS by PI single-staining,and to observe if there were typical apoptosis peaks.The apoptosis inducing effect and changing of mitochondria membrane potential of the CSS on the HepG-2 cells were studied by flow cytometry.The effect of intracellular Ca2+ level of CSS on the HepG-2 cells was measured by laser confocal microscope.Results CSS has growth inhibiting on the HepG-2 and seems to be enhanced with the increasing concentration of CSS,and its IC50 value was 46.16 μg·mL-1.The HepG-2 cells are characteristic apoptosis morphologic changed,and the apoptosis percentage is increased to 66.652% in the 50 μg·mL-1 dosage group.The cells cycle has been changed obviously that the progresses of cells cycle of G1 period and G2 period in high dosage group have been blocked,and the cellular proportion in G2 period is decreased by the function of CSS for 24 h.The mitochondria membrane potential of HepG-2 cells induced by CSS is decreased in various degrees.In addition,the intracellular Ca2+ level is increased by the function of CSS in the middle and high dose groups.Conclusions The CSS has obviously killing and apoptosis inducing effect on human hepatocarcinoma cell Line HepG-2 by the mechanism of decreasing the mitochondria membrane potential and increasing the intracellular Ca2+ level. Objective To discuss on mechanism of the killing and apoptosis inducing effect induced by total alkaloid in the CSS (Capparis spinosa L.saponin, CSS) on human hepatocarcinoma cell Line HepG-2.Methods The killing effect of the CSS on human hepatocarcinoma cell Line HepG -2 was observed by MTT method. Morphological observation of the HepG-2 cells was completed by fluorescence microscope. This test was signed to observe the changes of the cell cycle of HepG-2 cells affected by the CSS by PI single-staining, and to observe if there were typical apoptosis peaks.The apoptosis inducing effect and changing of mitochondria membrane potential of the CSS on the HepG-2 cells were studied by flow cytometry. the effect of intracellular Ca2 + level of CSS on the HepG-2 cells was measured by laser confocal microscope. Results CSS has growth inhibiting on the HepG-2 and seems to be enhanced with the increasing concentration of CSS, and its IC50 value was 46.16 μg · mL-1.The HepG-2 cells are characteristic apoptos is morphologic changed, and the apoptosis percentage is increased to 66.652% in the 50 μg · mL-1 dosage group. The cells cycle has been changed obviously that the progresses of cells cycle of G1 period and G2 period in high dosage group have been blocked , and the cellular proportion in G2 period is decreased by the function of CSS for 24 h. The mitochondria membrane potential of HepG-2 cells induced by CSS is decreased in various degrees. In addition, the intracellular Ca2 + level is increased by the function of CSS in the middle and high dose groups. Conclusions The CSS has obviously killing and apoptosis inducing effect on human hepatocarcinoma cell line HepG-2 by the mechanism of decreasing the mitochondria membrane potential and increasing the intracellular Ca2 + level.