Isolation, chemotaxonomic significance and cytotoxic effects of quassinoids from Brucea javanica.

Abstract A new quassinoid, bruceene A ( 1 ) along with seventeen known quassinoids ( 2 – 18 ) was isolated from the fruits of Brucea javanica . The structure of 1 was elucidated by extensive spectroscopic methods, and was further confirmed by single-crystal X-ray diffraction analysis. Isolation of similar quassinoids 1 – 3 as those in genus Ailanthus from genus Brucea , indicated the close chemotaxonomic relationship between these two genera, which further supported the phylogenetic study by DNA analysis. Compounds 5 , 7 , 10 and 12 with a 3-hydroxy-3-en-2-one moiety showed potent inhibitory activities against the MCF-7 and MDA-MB-231 cells with IC 50 values in the ranges 0.063–0.182 μM and 0.081–0.238 μM, respectively; while glycosidation at 3-OH significantly decreased the cytotoxicity. It was also found that the most potent compound 7 induced apoptosis in MCF-7 cells via the intrinsic mitochondrial apoptotic pathway.