Extraction And Biological Activity Of Two Kinds Of Shellfish Polysaccharides

Taking Bay Scallops(Argopectenirradias)and Chinese clams(Mactrachinensis)as raw materials,this paper optimizes the optimum extraction conditions of polysaccharides,analyzes the structure and composition of polysaccharides,studies the antioxidant indexes of polysaccharides in vitro,as well as the indicators of macrophage production.The antioxidant activity and in vitro immunity of two kinds of shellfish polysaccharides were determined.The results of the study are as follows:1.By using the single factor method,and the purity of polysaccharide was as the index,the effects of pepsin,compound protease,neutral protease,papain and alkaline protease on the enzymatic hydrolysis of scallop and clam were compared,the results showed that the suitable enzymes for hydrolyzing the scallop and clam were papain and pepsin,respectively.By using orthogonal method to optimize the enzymatic hydrolysis conditions,the optimum conditions hydrolyzing the scallop were enzymatic hydrolysis time 4 h,pH 6,temperature 60 ?,and the enzyme content was 2.5%,under this condition,the purity of the scallop polysaccharide extracted by membrane and alcohol precipitation was 84.75%.The optimum conditions for the extraction of clam by pepsin were 5 h,pH2,35?,and the amount of enzyme added was 2%,and the purity of clam polysaccharide was 13.82%.2.Structural analysis of the obtained polysaccharides from scallop and clam by infrared spectroscopy and DSC showed that the scallop polysaccharide contained carboxyl,methylene,sulfate groups and the furan ring,and the clam polysaccharide contains a carboxyl group,a methylene group and a sulfate group.The monosaccharide composition of the two polysaccharides was analyzed by PMP pre-stage derivatization high performance liquid chromatography.The results showed that the scallop polysaccharide consisted of only glucose,while clam polysaccharide was composed of mannose,glucosamine,galactose and glucose.3.The antioxidant activity of the two polysaccharides was determined by measuring the scavenging ability of hydroxyl radical(-OH)and DPPH free radicals.The results showed that the IC50 of DPPH of the scallop polysaccharide was 6.591mg/mL,the IC50 of-OH was 1.010 mg/mL;Clearance ability was 87.53% for-OH at the concentration of 8mg/ml,the DPPH free radical scavenging ability was reached.80% at the concentration of 12mg/mL;while for the clam,the IC50 of DPPH was 8.394mg/mL,and the IC50 of-OH was 4.067mg/mL.Under 16mg/ml,the clearance ability of-OH was 86.2%,and 78.82%,respectively.It could be seen that the vitro antioxidant activity of the scallop was significantly higher than that of the extracted clam polysaccharide.4.The scallop polysaccharide and clam polysaccharide were applied to macrophages to determine the effect on different indexes of macrophages.The results showed that scallop polysaccharide and clam polysaccharide could promote the macrophages to product NO and iNOS.At high concentration(100?g / ml or more)they had cytotoxicity on the macrophage,and at low concentration(100?g / ml or less),they had proliferation on the macrophages.