Extraction, characterization, and biological activity of polysaccharides from Sophora flavescens Ait.

- Four polysaccharide fractions were efficiently extracted from S. flavescens with pretreatment of mechanochemistry.
- Their structural characters, Mw, chemical and monosaccharide compositions were analyzed.
- The polysaccharide fractions have antioxidant and immunoregulatory activities.

Four water-soluble polysaccharides, designated as SF1, SF2, SF3 and SF4, were efficiently extracted from the roots of Sophora flavescens by mechanochemistry under the conditions of rotational speed of 400 rpm, grinding time of 10 min, powder to ball weight ratio of 1:20, and Na2CO3 loading of 7 wt%. The results obtained indicated that all of these four acid heteropolysaccharides are composed of rhamnose, arabinose, xylose, mannose, glucose and galactose, with the average molecular weights of 400.9, 98.6, 99.3, 42.7 kDa, respectively. In vitro, SF4 showed the most significant scavenging activity on superoxide radical, ABTS, and DPPH radical, while SF3 had the most significant scavenging activity on hydroxyl radical. Immunological tests demonstrated that SF1, SF2, SF3 and SF4 significantly stimulated nitric oxide production without cytotoxicity in macrophages and promoted splenocyte proliferation. These data suggest that the four polysaccharides fractions have the potential as novel natural sources of antioxidative and immunopotentiating agents.