Abstract
Xanthones are important chemical constituents of Garcinia xanthochymus and varied bioactivities including cytotoxicity. However, their anti-tumor mechanism has remained unknown. Here, we isolated and identified a new xanthone named garciniaxanthone I (1) and five known compounds from the bark of G. xanthochymus. Their structures were elucidated by NMR analysis and HRESIMS. The anti-proliferation activities of all isolated compounds were evaluated on four human tumor cell lines (HepG2, A549, SGC7901, MCF-7). The results demonstrated that the anti-proliferation activity of xanthone was related to the number and location of prenyl groups. We further found that garciniaxanthone I (GXI) could induce HepG2 apoptosis and enhance the expression of cleaved caspase-8, caspase-9, and caspase-3. GXI could also increase Bax level and concurrently reduce the overexpression of Bcl-2, Bcl-XL, Mcl-1, and surviving in HepG2 cells. Moreover, GXI could inhibit cell migration of HepG2 cells by inhibiting the expressions of MMP-7 and MMP-9. In summary, our study suggests that GXI could induce HepG2 apoptosis via the mitochondrial pathway and might become a lead compound for liver cancer treatment.