Isolation And Purification And Structure Identification Of Polysaccharide From Leucosceptrum Canum Smith And Antioxidant Activity Analysis In Vitro

Leucosceptrum canum Smith was researched in the object. The extraction condition of Leucosceptrum canum Smith polysaccharide by Ultrasonic Wave were optimized. Isolation and purification and structure identification of polysaccharide from Leucosceptrum canum Smith and antioxidant activity in vitro were analyzed.(1)Response surface methodology(RSM) was used to optimize the ultrasonic extraction conditions of polysaccharides from Leucosceptrum canum Smith based on the Box-Behnken design. The factors of ultrasonic power, solid to liquid ratio, ultrasonic time were analyzed. The results showed that both ultrasonic power and extraction time had significant effects on polysaccharide yield. The optimum extraction conditions were as follows: ultrasonic power 548 W, ratio of solid to liquid 1:30 g/mL, extraction time 55 min. Under the optimized conditions, the yield of polysaccharides was 17.59%, which was closed to the predictive yield of 17.74%.(2) polysaccharide from leucosceptrum canum smith was extracted with water at 80℃;Ultrafiltration and nanofiltration were used to isolation and purifiaction the polysaccharide;Severge method was used to remove the protein of leucosceptrum canum smith, Sephadex LH-20 Gel column was used to purificate the polysaccharides. The clearance of pigment was98.5% and the rate of protein was 100%. The purified polysaccharides were analyzed by UV spectroscopy which was proved neither protein nor pigment in, And identificated a single material by Thin layer chromatography plate.(3)The determination of molecular weight and purity of LCP was analysised by HPGPC,The monosaccharide components were analysised by QTOF-MS and HPLC, surface structure of LCP was analysised by SEM, The structure was confirmed by IR and NMR. The molecular weight of LCP was 354813 Da. The composition of monosaccharide was mannose-rhamnoseglucose- galacturonic acid- arabinose, molar ratio was: 0.19:0.35:0.64:0.26:0.47. The chemical structure of the target compound was confirmed by IR,1H-NMR,13C-NMR, the sugar configurations for β.(4)Analysis physiological activity of polysaccharide from Leucosceptrum canum Smith,vitro antioxidant activity were measured. Measurement of scavenging effect on DPPH radica,hydroxyl radica L(.OH), superoxide radica(O2-). Assay for inhibition of liver lipid peroxidationby FeSO4-H2O2-、liver mitochondria swelling by Fe2+-Vc, mice RBC hemolysis mediated by peroxyl free radicals. The experimental results show that the polysaccharide concentration of 1mg/mL, the scavenging activity are 85.48%、47.23%、77.68%, the value of IC50 are 0.44、5.91、0.50 mg/m L, polysaccharide from Leucosceptrum canum Smith can scavenging radical effectively. the polysaccharide concentration of 1.6 mg/mL, The inhibition on liver lipid peroxidati、liver mitochondria swelling、mice RBC hemolysis are 70.82%、26.34%、86.91%,The value of IC50 are 1.17、6.83、0.82 mg/mL, polysaccharide from Leucosceptrum canum Smith have antioxidant capacity.