Studies On The Isolation, Purification, Structure And Antioxidant Activity Of Polysaccharide From Castanea Mollissima Blume

Castanea mollissima Blume (Fagacaea) has been used both as a tonic and food. There are about 12-17 species around the world,about 4 species and a variety in China. The study on the polysaccharide of Castanea mollissima Blume huankantou reported in currently both at home and abroad.With Castanea mollissima Blume which bought in shaanxi zhen'an xian as raw material,this study applies modern techniques to extract and isolate and purify the polysaccharide of Castanea mollissima Blume.The purification components is characterized by the determination of the structure and composition.We use modern methods of functional evaluation to study Castanea mollissima Blume polysaccharide vitro antioxidant activity.The primary conclusions are as follows:1. The optimum condition with hot water extraction method with the orthogonal experiment design show as follows:the ratio of sample to water is 1:30, the temperature 85℃, the time 3 hours, and extract three times. Under this conditions, the extraction ratio of polysaccharide is 12.64%.2. The optimum condition with ultrasonic extraction obtained by the orthogonal experiment design show as follows:the ratio of sample to water is 1:25, ultrasonic time is 50 min,the temperature 75℃, the total time 3 hours,ultrasonic power 150W,and extract once. Under this condition, the extraction ratio of polysaccharide is 14.17%.3.Two fractions named CPS-a and CPS-b are isolated and purified from the polysaccharide extracts by the DEAE-52 ion-exchange and Sephadex G-100 gel filtration chromatogram,and the purity is identified by the specific optical rotation. The result showed that two fractions are all homogeneous.With the method of high performance gel permeation chromatography(HPGPC), the molecular weights of CPS-a and CPS-b are 34500Da and 52100Da.4.Monosaccharide composition analysis by paper chromatography and gas chromatography of CPS-a and CPS-b show that:CPS-a mainly consists of glucose, mannose, arabinose and xylose; CPS-b mainly consists of glucose, mannose, arabinose, xylose and fructose.5. Infrared spectroscopy analysis showed that polysaccharide form Castanea mollissima Blume has in the 3400cm-1,2900 cm-1,1640 cm-1,1400 cm-1,1075-1000 cm-1 have absorption peak, these regions are all charateristic absorption of polysaccharide. CPS-b have weaked absorption peak in the 1354 cm-1,1273 cm-1 and it caused S=O of sulfuric acid base and sulfonylureas acyl stretching vibration absorption,indicating sugar chains have sulfated polysaccharides.6. Experiments of antioxidant activity in vitro show that with the concentration of the Castanea mollissima Blume polysaccharide(CPS) increased the total reducing power and hydroxyl radical, superoxide radical and DPPH organic free radical scavenging abiliy have increased, showing a clear dose-effect relationship.