A New Stilbene Diglycoside from Rheum undulatum

A new stilbene diglycoside, piceatannol-3, 4'-O-$\beta$-D-diglucopyranoside (I), together with desoxyrhaponticin (II), emodin-1-O-$\beta$-D-glucopyranoside (III), and physcion-8-O-b-D-gluco-pyranoside (IV), were isolated from the rhizomes of cultivated Korean rhubarb rhizomes(Rheum undulatum), Jong DaeWhang, and the structures of 1-IV were identified on the basis of chemical and spectral evidences.