Cytotoxic caged-polyprenylated xanthonoids and a xanthone from Garcinia cantleyana

Five caged-xanthonoids, cantleyanone A (1), 7-hydroxyforbesione (2), cantleyanones B-D (4-6) and a simple xanthone, 4-(1,1-dimethylprop-2-enyl)-1,3,5,8-tetrahydroxyxanthone (3) together with eight other known compounds were isolated from Garcinia cantleyana. Significant cytotoxicity against MDA-MB-231, CaOV-3, MCF-7 and HeLa cancer cell-lines were demonstrated by cantleyanones B-D, 7-hydroxyforbesione, deoxygaudichaudione A and macranthol, with IC50 values ranging from 0.22 to 17.17 μg/ml.