Flavonoids from the stem bark of Bolusanthus speciosus

Three flavonoids (bolusanthols A-C), viz an isoflavan and two prenylated is oflavanones, were isolated from the stem bark of Bolusanthus speciosus in a ddition to four known flavonoids, 5,7,3'-trihydroxy-4'-methoxy-5'-gamma,gam ma -dimethylallylisoflavanone, 5,7,2'-trihydroxy-4'-methoxy-6,5'-di(gamma,g amma -dimethylallyl)isoflavanone, 3,5,7,3',4'-pentahydroxy-6-gamma,gamma -d imethylallylflavone and 5,7,2',4'-tetrahydroxy-8,3'-di(gamma,gamma -dimethy llallyl)-isoflavanone. The structure of the new compounds were determined t o be 4,2',3',4'-tetrahydroxy-6,7-methylenedioxyisoflavan (bolusanthol A), 5 ,7,3',4'-tetrahydroxy-5'-gamma,gamma -dimethylallylisoflavanone (bolusantho l B), acid 5,7,4'-trihydroxy-6,3'-di(gamma,gamma -dimethylallyl)isoflavanon e (bolusanthol C) by spectroscopic methods. (C) 2001 Elsevier Science Ltd. All rights reserved.