Preparation and in vitro antioxidant activity of lacquer polysaccharides with low molecular weights and their sulfated derivatives

Lacquer polysaccharide (LP) from the sap of the lac tree (Rhus vernicifera) was degraded by hydrochloric acid. The molecular weights (Mw) of hydrolysis products of lacquer polysaccharide (LPD) decreased with the increase of the reaction temperature. Sulfated derivatives (LPDSs) of LPDs were prepared by the reaction of LPDs with sulfur trioxide–pyridine complex (SO3·Py) in DMSO. The structures of polysaccharides were analyzed by GPC, FT-IR and 1H NMR spectroscopy. Reducing power, superoxide radical scavenging ability and metal chelating capacity were used for the evaluation of all polysaccharides in vitro. Results indicated that LPDS with moderate Mw and DS expressed good antioxidant capacity.