Study On The Preparation And Biological Activities Of Sulfated Crassostrea Gigas Polysaccharides

Crassostrea gigas is one of the important economic cultured shellfish in China,and its polysaccharide has rich biological activity and medicinal value.In this study,C.gigas polysaccharides?CGP?were used as materials to prepare sulfated C.gigas polysaccharides?SCGP?,and its physical and chemical properties as well as biological activity in vitro and in vivo,provide the theoretical basis for oyster polysaccharide utilization,the main contents and results are as follows:1.Sulfated polysaccharide from Crassostrea gigas?SCGP?was derived by using the chlorosulfonic acid-pyridine method.Based on the calibration with Dextran,SCGP relative molecular mass concentration is greater than 2×10⁶.The content of sulfate was 28.69%and the substitution value of DS was 0.66 by gelatin-barium chloride method.The structure of SCGP was analyzed by Fourier transform infrared spectroscopy and ¹³C nuclear magnetic resonance spectroscopy,which indicated that SCGP was mainly composed of C-6 sulfate-substituted polysaccharides.2.In vitro antioxidant test results showed that CGP and SCGP have the ability of reducing iron,scavenging DPPH·free radical,hydroxyl radical,superoxide anion radical and ABTS⁺·free radical,and SCGP scavenge ability is always stronger than CGP.3.SCGP activity in vivo CCl₄-induced acute liver injury model in mice and alcohol induced subacute liver injury model for evaluation.The activities of ALT and AST in serum?P<0.05?were found to be reduced significantly and MDA levels and SOD activity were enhanced in liver tissue?P<0.05?in high SCGP group.The drug-induced hepatocyte lesion was significantly reduced in the mice in the SCGP group under an inverted microscope compared with the model group.The results show that SCGP has a protective effect on liver injury.4.The inhibitory effects of SCGP on cells were evaluated using CCK-8 assay,and the apoptosis changes were analyzed by flow cytometry.The results showed that SCGP significantly inhibited the growth of three cell.The inhibitory effect of SCGP was better on AGS cells than other cells.The flow cytometry results showed that SCGP could effectively induce the apoptosis of AGS cells.5.Serum samples of alcohol-induced mice models of subacute liver injury were studied by metabolomics.Serum samples of SCGP-treated group and model mice group were studied.21distinct differential markers were obtained in OPLS-DA positive and negative ion modes.The content of L-Glutamine and L-Isoleucine were increased and the content of allantoin was reduced,indicating that SCGP improved impaired intestinal function and reduced oxidative stress in mice.