Bioactive benzophenones from Garcinia xanthochymus fruits

A MeOH extract of Garcinia xanthochymus fruits was subjected to activity-guided fractionation, yielding two new benzophenones, guttiferone H (1) and gambogenone (2). Compound 1 contains a seven-membered ring attached to the bicyclo[3.3.1]nonane system at positions 7 and 8 and displayed cytotoxicity in the SW-480 colon cancer cell line (IC50 = 12 mu M). Compound 2 has a novel benzophenone bicyclo [3.3.2] decane system and displayed cytotoxicity in the SW-480 colon cancer cell line (IC50 = 188,mu M). Both 1 and 2 induced apoptosis in SW-480 colon cancer cells and displayed antioxidant activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay (IC50 = 64 and 38.7 mu M, respectively). The structures of 1 and 2 were established by 1D and 2D NMR data analysis. Eleven known compounds, aristophenone A, alloathyriol, amentoflavone, 3,8"-biapigenin, cycloxanthochymol, (+/-)-fukugetin, (+/-)-fukugiside, guttiferone E, isoxanthochymol, (+/-)-volkensiflavone, and xanthochymol, were also obtained. The 11 known compounds were also tested against SW-480 colon cancer cells and in the DPPH assay.