Chemical Characterization and In Vitro Antioxidant Activity Evaluation of Polysaccharides from the Fruiting Bodies of the Red Heart Mushroom Phellinus pini (Higher Basidiomycetes)

Phellinus pini is a precious medicinal mushroom. Three water-soluble fractions of crude polysaccharides (PP30, PP60, and PP80) were obtained from the fruiting bodies of Ph. Pini. The basic chemical characterization and in vitro antioxidant activity of these 3 polysaccharides were determined. All 3 crude polysaccharides were heteropolysaccharide complexes with a small amount of protein (1.14-2.55%) and uronic acid (2.06-4.11%). The monosaccharide composition of PP30, PP60, and PP80, as a molar ratio, was mannose (1.00):glucose (18.7):galactose (0.92), fucose (0.47):3-0-Me-Gal (0.51):mannose (1.00):glucose (7.86):galactose (1.10), and rhamnose (0.12):fucose (0.32):xylose (0.17):3-0-Me-Gal (0.26):mannose (1.00):glucose (4.79):galactose (0.53), respectively. The in vitro antioxidant activities of crude polysaccharides were evaluated by 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, hydroxyl radical, and ferric-reducing antioxidant power methods. The antioxidant data obtained using these methods were in accordance with each other and decreased in the same order of PP80 > PP60 > PP30 at a concentration of 0.1-2.5 mg/mL.