Purification, chemical characterization and antioxidant activities of polysaccharides isolated from Mycena dendrobii

Two polysaccharides, MDP-1 and MDP-2, were obtained from the fermentation liquid of M. dendrobii by anion exchange chromatography and gel filtration. Their chemical structures were measured by FT-IR, GC, 1H and 13C NMR spectra, indicating the mainly compositions of mannose, xylose, and galactose for MDP-1; galacturonic acid, galactose and rhamnose for MDP-2. Furthermore, the antioxidant activities of MDPs were investigated, showing different antioxidant activities, in which MDP-2 performed noticeable, with excellent superoxide radical activity better than BHT, high DPPH radical activity (IC50 at 227 μg/mL) comparable with BHT, moderate reducing power activity and hydroxyl radical scavenging activity. The results indicated that the fermentation liquid of M. dendrobii could be used as a potential natural source of antioxidant.