Isolation, characterization and antioxidant activity of polysaccharide from Schisandra sphenanthera

A water-soluble polysaccharide (SSPP11) from Schisandra sphenanthera was purified by DEAE-cellulose and Sephadex G-100 columns. Structure of SSPP11 and its antioxidant activity was evaluated. Results showed that SSPP11 has a molecular weight of 5.3 Chi 10(3) Da and is composed of Man, Glu and Gal. A linkage analysis and NMR study revealed that SSPP11 has a backbone of -> 1)-D-Man-(6 ->, -> 1)-D-Manp-(2 ->, -> 1)-D-Glup(4 ->, -> 1)-D-Glup-(6 ->, -> 1)-D-Galp-(4,6 -> and -> 1)-D-Manp-(3,6 ->, with Man, Glu and Gal, which are distributed in branched chains. The Congo red absorption test revealed that SSPP11 has a triple helix stereo-configuration. Moreover, antioxidant activity of SSPP11 was stronger than the polysaccharide from Schisandra chinensis (Turcz.) Baill. In sum, this study demonstrates that a moderate molecular weight, triple helix stereo-configuration and higher degree of branching are beneficial for exerting antioxidant activity. (C) 2014 Elsevier Ltd. All rights reserved.