Flavonoids from the stem bark of Bolusanthus speciosus.

Abstract

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′-γ,γ-dimethylallylisoflavanone, 5,7,2′-trihydroxy-4′-methoxy-6,5′-di(γ,γ-dimethylallyl)isoflavanone, 3,5,7,3′,4′-pentahydroxy-6-γ,γ-dimethylallylflavone and 5,7,2′,4′-tetrahydroxy-8,3′-di(γ,γ-dimethylallyl)-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′-γ,γ-dimethylallylisoflavanone (bolusanthol B), and 5,7,4′-trihydroxy-6,3′-di(γ,γ-dimethylallyl)isoflavanone (bolusanthol C) by spectroscopic methods.