Prenylated xanthones and benzophenones from the fruits of Garcinia bracteata and their potential antiproliferative and anti-inflammatory activities.

Ten previously undescribed compounds, including five prenylated xanthones (1-5), two caged xanthones (16-17) and three rearranged benzophenones (27-29), together with nineteen known compounds were isolated from the fruits of Garcinia bracteata. Their structures were established on the basis of spectroscopic analysis, electronic circular dichroism calculations, and X-ray crystallographic data. Compound 17 was a caged xanthone bearing a rare 8, 8a-epoxy moiety. Compound 28 belonged to the rearranged benzophenones with rare 2, 7-dioxabicyclo-[2.2.1] heptane moiety fused at C-2 and C-3 respectively. The antiproliferative and anti-inflammatory activities of all isolated compounds were evaluated. Compounds 23 and 24 exhibited remarkable inhibitory activities against three human cancer cell lines (HepG2, T98, MCF-7) with IC50 values ranging from 3.21 ± 1.00 to 6.27 ± 1.03 μM. Moreover, compounds 20 and 24 also displayed significant inhibitory effects against NO production with IC50 values of 1.22 ± 0.01 and 1.77 ± 0.23 μM respectively. These results enrich the structural diversities of xanthones and benzophenones from Garcinia plants. Neobractatin (24) due to its anti-tumor and anti-inflammatory effects is worth further investigation in anticancer research.