Flavonoids from the stem bark of Bolusanthus speciosus

Three flavonoids (bolusanthols A-C), viz an isoflavan and two prenylated isoflavanones, were isolated from the stem bark of Bolusanthus speciosus in addition to four known flavonoids, 5,7,3'-trihydroxy-4'-methoxy-5'-gamma,gamma -dimethylallylisoflavanone, 5,7,2'-trihydroxy-4'-methoxy-6,5'-di(gamma,gamma -dimethylallyl)isoflavanone, 3,5,7,3',4'-pentahydroxy-6-gamma,gamma -dimethylallylflavone and 5,7,2',4'-tetrahydroxy-8,3'-di(gamma,gamma -dimethyllallyl)-isoflavanone. The structure of the new compounds were determined to be 4,2',3',4'-tetrahydroxy-6,7-methylenedioxyisoflavan (bolusanthol A), 5,7,3',4'-tetrahydroxy-5'-gamma,gamma -dimethylallylisoflavanone (bolusanthol B), acid 5,7,4'-trihydroxy-6,3'-di(gamma,gamma -dimethylallyl)isoflavanone (bolusanthol C) by spectroscopic methods. (C) 2001 Elsevier Science Ltd. All rights reserved.