Benzophenones and biflavonoids from Garcinia livingstonei fruits.

A series of 13 known compounds, including seven benzophenones [guttiferone A (1), guttiferone K (2), xanthochymol (3), guttiferone E (4), cycloxanthochymol (5), isoxanthochymol (6), and gambogenone (7)], five biflavonoids [amentoflavone (8), 3,8''-biapigenin (9), (+)-volkensiflavone (10), (+)-morelloflavone (11), and (+)-fukugiside (12)], and the xanthone derivative alloathyriol (13), were identified from the fruits of Garcinia livingstonei (Clusiaceae). This is the first time that compounds 2-7, 9, 12, and 13 have been reported in this species. The cytotoxicity of benzophenones 1 and 2 was assessed for their effect on HCT-116, HT-29, and SW-480 human colon cancer cell lines. Both compounds exhibited strong activity against HCT-116 and HT-29 cell lines with IC(50) values between 5 and 10 microM, and somewhat weaker activity with SW-480 cells (IC(50) values ranging from 18 to 25 microM).