A new biologically active flavonol glycoside from Psoralea corylifolia (Linn.).

A new biologically active flavonol glycoside (1) mp 264-265 degrees C, C32H38O20, [M]+ 742 (EIMS) has been isolated from the methanol-soluble fraction of the defatted seeds of Psoralea corylifolia (Linn.). It was characterised as the new flavonol glycoside 3,5,3',4'-tetrahydroxy-7-methoxyflavone-3'-O-alpha-L-xylopyranosyl(1-->3)-O-alpha-L-arabinopyranosyl(1-->4)-O-beta-D-galactopyranoside by several colour reactions, spectral analysis and chemical degradations. Compound 1 showed anti-microbial activity against various bacteria and fungi.