Chiral resolution and anticancer effect of xanthones from Garcinia paucinervis.

Bioassay-guided fractionation of the dichloromethane-soluble portion of the stems of Garcinia paucinervis led to the isolation of eight new xanthones, including three pairs of enantiomers, (+) and (-) paucinervins L-N (1a-3a, and 1b-3b), one optically pure compound, (-) paucinervin O (4), and one new analogue, paucinervin P (5), as well as thirteen known xanthones (6-18). Their structures were established by detailed analysis of extensive spectroscopic data. The absolute configurations of 1-4 were confirmed by ECD calculations. All the isolates 1-18 displayed antiproliferative effect against HL-60 with IC50 values ranging from 0.87 to 29.14 μM, of which compound 5 was the most active. Compounds 6, and 14 exhibited potential inhibitory activity against PC-3 cells, while compounds 5-7, 14, and 16-17 displayed cytotoxic potency against Caco-2 cells. A preliminary structure-activity relationship was also discussed.