Objective To study on the mechanism of growth inhibiting and apoptosis inducing effect of total alkaloid in the CSEO(Capparis spinosa L.essential oil,CSEO)on human hepatocarcinoma cell Line HepG-2.Methods The growth inhibiting effect of the CSEO on human hepatocarcinoma cell Line HepG-2 was measured by MTT method.Morphological observation of the HepG-2 cells was completed by fluorescence microscope.The changing of mitochondrion membrane potential induced by CSEO was observed by staining with Rhodamine123.Effect of the CSEO on intracellular Ca2+ level of the HepG-2 cells was measured by laser confocal microscope.Results The CESO has obvious growth inhibiting effect on the HepG-2 and seems to be dose-dependent,and its IC50 is 127.5 μg·mL-1.The characteristic apoptosis morpha of HepG-2 cells has been observed,and the apoptosis percentage increase to 44.447% in the 300 μg·mL-1 dosage group.In addition,the progress of cells cycle of G1 period has been blocked,and the cellular proportion in S and G2 period is decreased in the 75 μg·mL-1 and 150 μg·mL-1 dosage groups by the function of CSEO for 48 h.The mitochondria membrane potential(Δψm)effected by CESO is decreased,while the curve moves toward left.In addition,the intracellular Ca2+ level is increased by the function of CESO in the middle and high dose groups.Conclusions The CESO has obviously growth inhibiting 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 study on the mechanism of growth inhibiting and apoptosis inducing effect of total alkaloids in the CSEO (Capparis spinosa L. essential oil, CSEO) on human hepatocarcinoma cell line HepG-2.Methods The growth inhibiting effect of the CSEO on human hepatocarcinoma cell Line HepG-2 was measured by MTT method. Morphological observation of the HepG-2 cells was completed by fluorescence microscope. The changing of mitochondrion membrane potential induced by CSEO was observed by staining with Rhodamine 123. Effect of the CSEO on intracellular Ca2 + level of the Results The CESO has obvious growth inhibiting effect on the HepG-2 and seems to be dose-dependent, and its IC50 is 127.5 μg · mL-1.The characteristic apoptosis morpha of HepG- 2 cells has been observed, and the apoptosis percentage increase to 44.447% in the 300 μg · mL -1 dosage group. In addition, the progress of cells cycle of G1 period has been blocked, and the cellular proportion in S and G2 period is decreased in the 75 μg · mL-1 and 150 μg · mL-1 dosage groups by the function of CSEO for 48 h. The mitochondria membrane potential (Δψm) effected by CESO is decreased, while the curve moves toward left.In addition, the intracellular Ca2 + level is increased by the function of CESO in the middle and high dose groups. Conclusions The CESO has obviously growth inhibiting 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.