A novel phytoestrogen compound, 3'-prenyl-4'-methoxy-isoflavone-7-O- beta-D-(2''-O-p-coumaroyl)glucopyranoside, has been isolated from the EtOAc-soluble fraction of the stems of Sopubia delphinifolia and has been identified by chemical and spectral analysis. Pharmacological examination of the compound showed it to have estrogenic activity.