Isolation, Purification And Biological Activity Of Polysaccharides From Allium Chinense G. Don

Response surface methodology was selected to optimize for the inner ebullition extraction processes of polysaccharide from ShengMi Allium Chinense. Based on the experiment of a single factor, the mathematical regression model was established about the dependent variable’s(extraction yield of polysaccharide)and independent variables (extraction time, ratio of solid to liquid and extraction temperature) through Box-Benhnken design and RSM. The optimum extraction conditions were as follows:85℃of extraction temperature,17:1of liquid feed ratio and6min of extraction time. The yield of polysaccharide extracted under the optimal conditions reached34.7%.Polysaccharides was extracted from ShengMi Allium Chinense with inner ebullition extraction processes, isolated and purified by DEAE ion-exchange cellulose and Sephadex G-75gel chromatography, polysaccharide eluted with water and NaCl were obtained. The identification of purification with Sephadex G-200gel chromatography implied that they were both homogeneous polysaccharides. The primary structure of the two groups is consistent. UV spectral analysis showed that two groups of polysaccharides is non-protein binding polysaccharide. Infrared spectrum of polysaccharides indicated that they had typical characteristic absorption peaks of polysaccharides. Infrared spectral analysis showed that polysaccharide eluted with water and NaCl are both have α-Dpyranoid ring structure. X-ray diffraction showed that the polysaccharide samples are still in the amorphous state. Estimating by high performance gel permeation chromatography, the molecular weight of polysaccharide eluted with water was16460Da, the molecular weight of polysaccharide eluted with NaCl was65310Da. The purity of polysaccharides eluted with water and NaCl were92.15%and85.41%.The comparative study of the oxidation resistance in vitro of two groups of polysaccharides, results were as follows:they both had certain remove hydroxyl radicals, superoxide radical, DPPH radical ability, but the effects was far less than Vc; The antioxidant of polysaccharide eluted with water is stronger than the other; The radical scavenging ability was effected by the concentration, it increases with increasing concentration. The polysaccharide eluted with water showed the strongest DPPH scavenging ability, could be achieved to51.24%, scavenging ability of-OH was less effective, scavenging ability of O2--was the weakest.The results of microassay shown that the two components of polysaccharide from ShengMi Allium Chinese inhibited mice intestinal a-glucosidase activity in vitro, inhibition rate of polysaccharide eluted with NaCl was greater, could be achieved to43.48%; under the same reaction time, inhibition rate of polysaccharide eluted with water was higher than another component; volume of addition to20μL, inhibitory activity of polysaccharide could achieve maximum; Increased with pH, inhibitory activity of sample increased, but the pH to10.52, inhibitory activity was reduced. Inhibition rate of polysaccharide eluted with water and NaCl in pH10.52were46.79%and47.89%.