Purification, composition analysis and antioxidant activity of different polysaccharides from the fruiting bodies of <i>Pholiota adiposa</i>

Abstract

Three water-soluble polysaccharide fractions (PAP1-1, PAP1-2 and PAP2-1) were isolated and purified from the fruiting bodies of Pholiota adiposa by diethylaminoethanol (DEAE) Sepharose fast flow column and superdex^TM 200 column chromatography on an AKTA Purifier system. Results of high-performance size-exclusion  chromatography (HPSEC) indicated that the average molecular weights of PAP1-1, PAP1-2 and PAP2-1 were 2.3 x 10⁶ Da, 8.8 x 10³ Da and 2.1 x 10⁶ Da, respectively. Monosaccharide compositions analysis revealed that PAP1-1 and PAP2-1 were both mainly composed of glucose, and PAP1-2 was composed of rhamnose and  glucose with a mole ratio of 1:3.61. The evaluation of antioxidant activity suggested that PAP1-1 with  β-configuration glycosidic bond exhibited stronger scavenging activity of superoxide radical and hydroxyl  radical than PAP1-2 and PAP2-1 contained both α- and β-configuration glycosidic bond, and should be  explored as a novel potential antioxidant. Available data obtained with in vitro models suggested that  antioxidant activity of polysaccharide may be related to the configuration of glycosidic bond.

Key words: Pholiota adipose, polysaccharide, purification, antioxidant activity.