Isolation and identification of stilbenes in two varieties of Polygonum cuspidatum

Abstract

The roots of two varieties of Polygonum cuspidatum (Hu Zhang and Mexican Bamboo) were analyzed for resveratrol and analogues. The roots of each variety were dried and ground into a powder. The powdered roots were then extracted with methanol and ethyl acetate. The ethyl acetate fraction of the Mexican Bamboo was then subjected to fractionation and purification using silica gel column chromatography and semipreparative HPLC. In addition to resveratrol (3,5,4'-trihydroxystilbene), three stilbene glucosides were identified by 1H NMR, 18C NMR, and MS. The stilbene glucosides were shown to be a piceatannol glucoside (3,5,3',4'-tetrahydroxystilbene 4'-O-β-D- glucopyranoside), resveratroloside (3,5,4'-trihydroxystilbene 4'-O-β-D- glucopyranoside), and piceid (3,5,4'-trihydroxystilbene 3-O-β-D- glucopyranoside). The levels of the piceatannol glucoside and piceid were twice as high in the Mexican Bamboo as compared to the Hu Zhang.