Cytotoxic prenylated xanthone derivatives from the twigs of .

A new prenylated xanthone, kaennacowanol D (), was isolated from the twigs of together with 22 known analogs. The structure of the new metabolite was elucidated by extensive spectroscopic analysis, particularly using HRMS and NMR. Kaennacowanol D is the first example of a natural xanthone containing a levulinyl group incorporated at the terminal prenyl unit ester bond. Cytotoxic evaluation of the isolated compounds on human cancer cells showed that jacareubin (), 2-prenylisojacareubin (), nigrolineaxanthone E () were significantly active against KB and Hela S3 cell lines with IC values ranging from 1.78 to 9.52 µM, while and also suppressed the growth of MCF-7, Hep G2, and HT-29 cells with IC values lower than 10 µM.