Physicochemical properties and antioxidant activities of polysaccharides isolated from Choerospondias axillaris by ethanol fractional precipitation method

Two new polysaccharides( CAP-60 and CAP-80) were fractionated from the crude polysaccharides of Choerospondias axillaris by 60%( v / v) and 80%( v / v) ethanol,successively. A third fraction CAP- S was obtained from the supernatant by freeze drying. Neutral sugar,uronic acid and protein contents were determined by analytical chemistry methods,and their spectral characteristics were determined by FTIR spectrometer.DPPH free radical and hydroxyl radical scavenging test,as well as reducing power were applied to evaluate the antioxidant activities of these three fractions.The results indicated that the total sugar of CAP-60,CAP-80 and CAP- S were 94.95% ± 2.51%,71.50% ± 2.02% and 35.18% ± 2.06%,respectively. They all contained uronic acids in their structures,which were consistent with the absorption peaks of 1700 ~1600 cm- 1in the infrared spectrum.What's more,CAP- S possessed the strongest antioxidant activities among these three antioxidant systems above,but was still inferior to ascorbic acid even under the highest concentration.