Triterpenes from Mucuna birdwoodiana.

Methanolic extracts of the stalks of Mucuna birdwoodiana on acid hydrolysis and subsequent methylation with diazomethane provided four triterpene sapogenols. On the other hand, investigation of glycosides after methylation of the same extract led to the isolation of four triterpene glycosides. On the basis of chemical and spectral evidence, their structures were characterized as methyl asiatate, methyl maslinate, two new sapogenols, methyl 1 beta,2 alpha,3 beta,23-tetrahydroxyolean-12-en 28-oate (mucunagenin a), its urs-12-en isomer (mucunagenin b), 3-O-(6-O-methyl-beta-D-glucuronopyranosyl) methyl asiatate 3-O-[alpha-L-arabinopyranosyl(1----2)]-6-O-methyl-beta-D-glucur onopyranosyl methyl maslinate, 3-O-[alpha-L-arabinopyranosyl(1----2)]-6-O-methyl-beta-D-glucur onopyranosyl methyl asiatate and 3-O-(6-O-methyl-beta-D-glucuronopyranosyl) asiatic acid 28-O-beta-D-glucopyranoside.