Cytotoxic caged-polyprenylated xanthonoids and a xanthone from Garcinia cantleyana

Abstract Phytochemical studies on the leaves and trunk bark of Garcinia cantleyana yielded five caged-xanthonoids including one tetra- and four tri-prenylated xanthones, cantleyanone A ( 1 ), 7-hydroxyforbesione ( 2 ) and cantleyanones B–D ( 4 – 6 ), as well as a simple xanthone, 4-(1,1-dimethylprop-2-enyl)-1,3,5,8-tetrahydroxyxanthone ( 3 ). Eight other known compounds, deoxygaudichaudione A, gaudichaudione H, friedelin, garbogiol, macranthol, glutin-5-en-3β-ol, and a mixture of sitosterol and stigmasterol were also isolated. Their structures were elucidated by means of spectroscopic data and comparison of their NMR data with literature values. Significant cytotoxicity against MDA-MB-231, CaOV-3, MCF-7 and HeLa cancer cell-lines was demonstrated by cantleyanones B–D, 7-hydroxyforbesione, deoxygaudichaudione A and macranthol, with IC 50 values ranging from 0.22 to 17.17 μg/ml.