FLAVANONE AND CHALCONE DERIVATIVES FROM CRYPTOCARYA-KURZII

Four complex flavanones, kurziflavolactones A 2!, B 3!, C 4!, and D 5! and a complex chalcone 6 with an unprecendented carbon side chain on the flavanone or chalcone A ring have been isolated from a Malaysi an plant, Cryptocarya kurzii (Lauraceae). Their structures were determ ined by extensive spectroscopic analysis, especially 2D nmr experiment s. Compounds 3 and 6 showed slight cytotoxicity against KB cells, with IC50 values of 4 and 15 mug/ml, respectively. A biosynthetic pathway for the formation of these compounds is suggested.