Identification of oxidation products of 2,3,5,4′-tetrahydroxystilbene 2-o-β-d-glucopyranoside from polygonum multiflorum thunb with H ₂o ₂

The major stilbene glycoside, 2,3,5,4′-tetrahydroxystilbene 2-O-β-d-glucopyranoside (PM-SG), was purified from the ethanol extract of the roots of Polygonum multiflorum Thunb. In order to better understand the antioxidation mechanism of PM-SG, PM-SG was allowed to react with H ₂O ₂, and the reaction products were isolated by chromatography and identified by liquid chromatography-mass spectrometry and nuclear magnetic resonance. The formation of a major product, a dimer of PM-SG, indicated that the C ₅ phenolic group on PM-SG was more reactive toward the hydrogen abstraction. PRACTICAL APPLICATIONS The root of Polygonum multiflorum Thunb is an important medicinal plant and has been used for over several thousand years in China. A major stilbene glucoside, 2,3,5,4′-tetrahydroxystilbene 2-O-β-d-glucopyranoside (PM-SG) is known as the active antioxidant of this plant material. In the present study, structural determination of the oxidation products from the reaction of PM-SG with H ₂O ₂ was carried out in order to allow better understanding of the antioxidant mechanism of this compound.