Structural Characterization and Antioxidant Activity of a Novel Alkaline-Soluble Polysaccharide from Patrinia villosa

A novel alkaline-soluble polysaccharide (PVPS-3), obtained from Patrinia villosa by 9.0% NaOH extraction, was fractionated by anion-exchange and gel filtration chromatography. Using Fourier infrared spectrometry, gas chromatography, methylation, and NMR, we determined PVPS-3 to be a 2.61 kDa heteropolysaccharide composed of L-arabinose, D-mannose, D-glucose, and D-galactose in a ratio of 2.3:1.1:4.9:1.2. Purified PVPS-3 showed concentration-dependent scavenging activity of 2,2-diphenyl-1-picrylhydrazyl radical and moderate hydroxyl radical scavenging (IC50 1.5 mg/mL) compared with crude polysaccharide (IC50 2.3 mg/mL). PVPS-3 is promising as a potential antioxidant.