In Vitro Antioxidant activities and anti-diabetic effect of a polysaccharide from Schisandra sphenanthera in rats with type 2 diabetes.

A water soluble polysaccharide (SSPW1), with an average molecular weight of 191.18KD, was isolated and purified from the water extract of Schisandra sphenanthera by DEAE-52 and Sephadex G-100 column chromatography. SSPW1 contained 48.92% neutral sugar, 5.56% proteins and 42.83% uronic acid, and were composed of rhamnose, arabinose, mannose, galactose, glucose at a molar ratio of 13.52, 5.69, 3.92, 41.28 and 35.59. In vitro experiment showed that SSPW1 have a satisfactory scavenging effect on superoxide anion free radical, hydroxyl radical and DPPH free radical. In vivo experiment showed that SSPW1 could increase the body weight, improve the glucose tolerance, reduce FBG, and elevate the levels of FINS and the value of ISI in the diabetic rats. In addition, SSPW1 could reduce the MDA content, and increase GSH-PX, CAT and SOD activities. These results suggest that SSPW1 has both in vitro and in vivo antioxidant effect, which may be closely related to its antidiabetic effect.