Prenylated pterocarpanes from Erythrina melanacantha.

: The stem bark of Erythrina melanacantha ssp. melanacantha Taub. ex Harms. afforded one new and five known prenylated pterocarpanes (phaseollin, isoneorautenol, erybraedin A, phaseollidin, and homoedudiol). The new compound was identified as 2',3'-epoxy-homoedudiol [3-hydroxy-8-(3,3-dimethyl-oxiranyl-methyl)pterocarpane]. All structures were elucidated by interpretation of their 1D and 2D NMR spectra.