ObjectiveTo explore the antitumor effect of solanine and its mechanisms. MethodsThe in vivo antitumor effect of solanine was observed using models developed through in vivo transplantation of tumor cells; In vitro lines of sensitive antitumor cells were selected from the digestive system using MTT assay; The effect of solanine on cell morphology was observed using transmission electronic microscopy; The morphology of apoptotic cells was observed using Annexin V/PI double staining and laser confocal scanning microscopy (LCSM); The rate of cell apoptosis was measured using Annexin V/PI double staining and flow cytometry; The concentration of intracellular Ca2+ ([Ca2+]i) was determined using Fluo-3/AM staining and LCSM; The membrane potential of cellular mitochondria was determined using TMRE staining and LCSM; The protein expression of Bcl-2 and Bax was measured using immunological marking and LCSM; And the activity of caspase-3 was measured using the colorimetric method. ResultsSolanine could inhibit the growth of tumor weight in S180 tumor-bearing mice and prolong the survival time of H22 tumor-bearing mice. MTT assay revealed that HepG2 cells were quite sensitive to solanine because solanine could induce morphological changes in HepG2 cells, with the rate of early apoptosis being 4%, 8.5%, and 20.1%, for HepG2 cells treated for 24 h with solanine at concentration of 0.4, 2, and 10 μg/mL, respectively. Solanine could raise the [Ca2+]i and lower the membrane potential. It could reduce the protein expression of Bcl-2 while increase that of Bax, thus increasing the activity of caspase-3. ConclusionThe obvious antitumor activity of solanine in human hepatocarcinoma is demonstrated. This inhibitory effect is achieved through solanine decreasing the Bcl-2/Bax ratio, thus increasing [Ca2+]i, which could enhance the enzymatic activity of the caspase family, thus inducing the apoptosis of HepG2 cells.