Purification, chemical characterization and in vitro antioxidant activities of alkali-extracted polysaccharide fractions isolated from the fruits of Schisandra chinensis

The alkali-extracted crude polysaccharide was extracted from the fruits of Schisandra chinensis, and further purified by DEAE-cellulose and Sepharose CL-6B chromatography, giving three polysaccharide fractions coded as ASPS-a-1, ASPS-b-2 and ASPS-b-3. In this study, their chemical and physical characteristics of polysaccharide fractions and antioxidant capacity, including scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, chelating ability, hydroxyl radicals and superoxide radicals, were evaluated. The results showed that ASPS-b-3 exhibited significantly antioxidant activity at a concentration-dependent manner. The alkali-extracted polysaccharide fraction can be developed to be new antioxidant drug.