The Research Of Isolation Purification And Structure Charactor Of Polysaccharide From Gonad Of Sea Urchin Strongylocentrotus Intermedius

A water-soluble sea urchin polysaccharide(SUP)was prepared from the gonad of sea urchin(Strongylocentrotus intermedius)by protease-assisted aqueous extraction,precipitated with ethanol,and then hydrolyzed with alpha-amylase and finally purified with gel filtration chromatography.Fourier transform infrared spectroscopy,methylation analysis,and two-dimensional nuclear magnetic resonance spectrum was performed to reveal the monosacchride composition.Radical-scavenging activity of SUP including DPPH,hydroxyl and superoxide anion O2 was measured by electron spin resonance(ESR).The results showed that the yield of SUP was 8.73%.Gel permeation chromatography showed that SUP was homogenous with average molecular weight of 4.4 kDa.The main component of SUP was mannose except for a small amount of glucose.and N-acetyl glucosamine.The chemical composition of SUP was sugar 46.25%,protein 2.85%and glucosamine 6.75%.Result obtained from fourier transform infrared spectroscopy,methylation analysis,and two-dimensional nuclear magnetic resonance spectrum revealed that SUP backbone was compose of residues of 1,4-linked mannose and 1,3-linked mannose interval arranged in a proportion of 2 to 1 and branched via 1?4,6-linked mannose residues.SUP exhibited a dose-dependent free radical scavenging activity as shown by its 2,2-diphenyl-1-picrylhydrazyl(DPPH),superoxide anion and hydroxyl radical inhibition.These results suggest that SUP has good antioxidative activity.These findings suggested that sea urchin polysaccharides have potential as functional food.The structure of SUP was described as below:...