Study On Separation,Purification And Bioactivity Of Polysaccharides From Bacca Sedge

Bacca sedge, as one kind of medicine food homology affinal drug and diet cereals in Southwest, was investigated. The extraction ratio was selected as response value. The response surface method was used to optimize the polysaccharide extraction process. The crude polysaccharide was separated and identified by using the viscometer and precolumn derivatization High Performance Liquid Chromatography?HPLC?. The chemical luminescence method was used to measure the superoxide anion free radicals, hydrogen peroxide, hydroxyl radical, DPPH scavenging and DNA damage protection. Besides, antibacterial activity was detected. The main results were as follows:?1? The single factor and response surface methodology experiments showed that, when ultrasonic time was 25 min, ratio of material to liquid was 1:38 g/m L, water temperature was 80 ?, and water extraction time was 1.7 h, the extraction yield of polysaccharides from Bacca sedge reached to 23.82%. The influence was very significant and showed as followed:water extraction temperature > solid-liquid ratio > ultrasonic time > water extraction time.?2? With the increasing of the temperature, heat treatment time and addition of Vc, H₂O₂, and metallic ions, the viscosity of the crude polysaccharides decreased. The viscosity increased under the conditions such as high concentration of polysaccharides, strong acid or alkali. The results of HPLC analysis showed that, the purified polysaccharides of Bacca sedge consisted of rhamnose?Rham?, glucuronic acid?GLC?,and glucose?GLC?.?3? The maximum clearance rate of protein and polysaccharide preservation rate were obtained by using Sevage method for three times. The purification conditions of DEAE-52 cellulose column chromatography were as followed: the elution concentration was 5mg/m L, flow rate was 1.0m L/min, time was 20min/tube, and sampling amount was 25 m L. Then purification was conducted by Sephadex G-100.The strong and symmetric peaks were obtained, respectively, which illustrated the high purity of the purified polysaccharides with single component.At last, purified polysaccharides powder was obtained after dialysis and freeze drying.?4? With the increasing of polysaccharides concentration, the scavenging ability of hydroxyl radicals, superoxide, hydrogen peroxide, DPPH and DNA damage protection increased. The dose-effect relationship was presented. The antibacterial properties experiments showed that it presented significant antibacterial effect on Salmonella and Staphylococcus aureus, followed by Bacillus cereus and E. sakazakii. The antibacterial effect remained with the increasing of polysaccharides concentration. There was no inhibitory effect on Proteus mirabilis.