Study On Isolation Ang Purification,structure Characterization And Activeties Of Polysaccharide From Porphyra Haitanensis

Porphyra haitanensis is well known for its nutritional value and health value.Polysaccharides from Porphyra haitanensis have been found to have biological activities of radical scavenging,anti-cancer,immune-modultating and so on.Extraction technology,separation and purification technology,level structure and physical and chemical properties and biological activities of polysaccharide from Porphyra-haitanensis were studied.Therefore,basic data for development of polysaccharide from Porphyra haitanensis was offered.In this study,polysaccharide from Porphyra haitanensis was acquired by the method of microwave-assisted extraction.In the process of single-factor experiment,microwave power,time,liquid-solid ratio were three main factors on extraction rate.Then,the extraction course was optimized by the Response Surface Analysis method.300W microwave power,8 minutes extraction duration and the liquid-solid ratio of 50 were the optimum extractions.The virtual maximum extraction rate of Porphyra haitanensis polysaccharide was 3.58%.During the separation and purification of crude polysaccharide from Porphyra haitanensis,two kinds of methods(Sevage deproteinization method and enzyme combined with Sevage deproteinization method)of removing protein from crude polysaccharide from Porphyra haitanensis were studied.And the relationship between the times of removing protein and protein content and the loss of crude polysaccharide from Porphyra haitanensis was compared.The research results showed that:the second method not only can increase the removal rate of protein,but also can reduce loss of crude polysaccharide greatly,compared with Sevage deproteinization method.So enzyme combined with Sevage deproteinization method only by two times was chosed.Part-pure product of Polysaccharide from Porphyra haitanensis—PYH was obtained after ethanol precipitation and freeze drying.PYH was separated and purified into three fraction(neutral Polysaccharide PYH1,acidic Polysaccharide PYH2 and PYH3)by DEAE Cellulose-52 and Sephadex G-100 column chromatography.The ultraviolet spectroscopy showed that typical absorption of protein or nucleic acid can not be observed in PYH1,PYH2 and PYH3.High performance liquid chromatography(HPLC)analysis results showed that PYH1,PYH2 and PYH3 were the homogeneous components.Infrared spectroscopy analysis showed that PYH2 and PYH3 were ?-heterosac-charides with pyran and acetyl amino group,the configuration of PYH1 was ?-glycosidic.PYH1,PYH2 and PYH3 contained sulfate group and 3,6-anhydrogalactose.The monosaccharide standards and derivatives of PYH1 hydrolysate and PYH2 hydrolysate were analyzed by Gas chromatography,and the results showed that PYH1 was consisted of galactose,arabinose and xylose;PYH2 was main consisted of galactose,and has a few of arabinose,xylose mannose and glucose;Then we studied polysaccharide from Porphyra haitanensis physical and chemical properties.The results showed that PYH2 was easy to dissolve in dilute acid and dilute alkali.Not dissolvable in ethanol,acetone,and other organic solvents.Thermal stability of PYH2 was stable in acid solvents and not stable in alkaline solvents.PYH2 did not contain reducing sugar,no starch,non-phenolic or tannin.Composition of sulfate group of PYH1,PYH2 and PYH3 were 5.43%,3.68%,3.84%;Composition of 3,6-anhydrogalactose of PYH1,PYH2 and PYH3 were 4.61%,7.46%,3.43%;Composition of galactose of PYH1,PYH2 and PYH3 were 33.92%,31.26%,26.87%?The bioactivities properties of polysaccharides from Porphyra-haitanensis included radical scavenging in vitro experiments and inhibition a-amylase experiments and The study of microbial flora were investigated?The results showed that PYH2 have scavenging abilities against 1,1-diphenyl-2-picrylhydrazyl radical(DPPH-),hydroxyl radical(·OH)and superoxide anion(·02-).The effect of deoxidize activity of PYH2 was also intensified.PYH2 can inhibit a-amylase obviously,which indicated PYH2 can decrease the blood glucose level.Through the experiment,microbes of PYH2 were almost of gram-negative bacteria and PYH2 had strong inhibitory effect on gram-positive bacteria.