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.