High-speed counter-current chromatography separation and purification of resveratrol and piceid from Polygonum cuspidatum

High-speed counter-current chromatography (HSCCC) was applied to the separation and purification of resveratrol and piceid from the dried roots (20.0 g) of Polygonum cuspidatium. The EtOAc extracts were separated with chloroform–methanol–water (4:3:2, v/v). Resveratrol was identified in fraction 5. The water extracts were separated first with EtOAc–EtOH–water (10:1:10, v/v) and then with the same solvent system at the modified volume ratio of 70:1:70. Yields of resveratrol and piceid obtained were 2.18% and 1.07%. Chemical structures of the purified resveratrol and piceid were confirmed by electrospray ionization MS and 1H nuclear magnetic resonance spectroscopy.