Characterization of antioxidant polysaccharides from Auricularia auricular using microwave-assisted extraction

Abstract

Influence of microwave-assisted extraction (MAE) to the characterization and corresponding antioxidant activity of polysaccharides from Auricularia auricula (AAP) was determined. According to gas chromatography-mass spectrometry, high performance size exclusion chromatography, Fourier transform infrared spectroscopy, partial acid hydrolysis, periodic acid oxidation, Smith degradation, methylation analysis and atomic force microscopy, AAP was a heteropolysaccharide (composed of glucose, galactose, mannose, arabinose and rhamnose at the molar ratio of 37.53:1:4.32:0.93:0.91) with the molecular weight of 2.77×10(4) Da, observed as a spherical lump, and the backbone of AAP was mainly composed by glucose with (1→3) linked. Moreover, AAP exhibited significant in vitro antioxidant activity in scavenging free radicals (ABTS, DPPH, superoxide and hydroxyl radicals), in lipid peroxidation and reducing power assays. The present result suggested that AAP by MAE had low molecular weight and remarkable antioxidant capability.