Cytotoxic xanthone derivatives from the twigs of Garcinia oligantha

Ten undescribed xanthone derivatives, garoliganthins A−I and oliganthaxanthone C, along with eight known compounds, were isolated from the twigs of Garcinia oligantha Merr. Their structures and absolute configurations were determined by extensive spectroscopic methods, single-crystal X-ray diffraction analysis, electronic circular dichroism analysis, and chiral HPLC/HPLC-CD analysis combined with density functional theory calculations. Garoliganthin A is an unprecedented tetrahydro-xanthone derivative possessing a bicycle [3.2.2] nonane skeleton, and garoliganthins B-E are the first examples of a new class of rearranged xanthone derivatives with six-membered lactone core scaffold. The cytotoxic effects of the isolates on four human cancer cell lines (HeLa, PC-3, A549, and K562) were measured using an MTT assay. Seven compounds showed good inhibitory activities against four cancer cell lines with IC50 values ranging from 2.1 to 16.8 μM. Ten undescribed xanthone derivatives were isolated from the twigs of Garcinia oligantha Merr. Garoliganthin A is the first representative of a novel type of tetrahydro-xanthone derivative possessing a bicycle [3.2.2] nonane skeleton. [Display omitted] •Ten undescribed xanthone derivatives were isolated from Garcinia oligantha.•Garoliganthin A is an undescribed xanthone with bicycle [3.2.2] nonane skeleton.•Garoliganthins B-E are undescribed rearranged xanthones with lactone core scaffold.•Seven compounds exhibited mild to moderate cytotoxic activities.