Anticancer activity of sesquiterpenoids extracted from Solanum lyratum via the induction of mitochondria-mediated apoptosis

Sesquiterpenoids are a major type of compound found in Solanum lyratum (S. lyratum). The present study aimed to investigate whether sesquiterpenoids from S. lyratum demonstrated cytotoxicity against the MCF-7, HCT-8, A-549, SGC-7901 and BEL-7402 cell lines, and the mechanism of solajiangxin H and lyratol D, which exhibited high cytotoxicity against SGC-7901 cells (half maximal inhibitory concentration, IC₅₀=4.8 and 5.9 µg/ml), was associated with mitochondria-mediated apoptosis. The results of the Cell Counting Kit-8 assay indicated that 15 sesquiterpenoids had cytotoxicity against the aforementioned cultured cells. The results of DAPI staining and western blot analysis, used to study the anticancer mechanisms of solajiangxin H and lyratol D in SGC-7901 cells, suggested that solajiangxin H and lyratol D induced the apoptosis of SGC-7901 cells significantly (P<0.01), downregulated the expression of the antiapoptotic proteins B-cell lymphoma (Bcl)-2 and survivin, and upregulated the expression of the proapoptotic proteins Bcl-2-like protein 4, second mitochondria-derived activator of caspase, cleaved (c)-caspase-3 and c-caspase-9. The present study therefore demonstrated that 15 sesquiterpenoids from S. lyratum exhibited anticancer activity in MCF-7, HCT-8, A-549, SGC-7901 and BEL-7402 cells, and that the anticancer mechanisms of solajiangxin H and lyratol D may be associated with mitochondria-mediated apoptosis. Additionally, the present study provides evidence in support of the hypothesis that S. lyratum may be a promising candidate for the development of novel cancer therapies.