Extraction,Isolation,Purification,Structure Identification And Biological Activity Research On Sargrassum Thunbergii

Sargassum thunbergii,affiliated to the brown algae door,mariko outline,fucus,sargassaceae,sargasso genera.Relatively broad coastal distribution at home and abroad,it is rich in resources.Sargassum thunbergii has a high application value,it is widely used in food,medicine,etc.Sargassum thunbergii contain protein,fiber,amino acids,and minerals and other nutrients,and also contains a certain amount of biological active substances,such as polysaccharides,polyphenols,polyunsaturated fatty acids and so on.The active material gives the rat tail algae a variety of biological activity,such as antitumor activity,antioxidant activity and anticoagulant activity and fall blood sugar,blood lipid activity,etc.Polysaccharide substances caused the wide attention of researchers both at home and abroad in recent years,however,so far,Research on PST less reported.In this paper,the technological conditions of extracting PST,purification,physical and chemical properties,the initial structure and antioxidant and immune activity and in vitro digestion conditions were studied and analyzed.1?Optimum extraction conditions of PSTThe Influences on water leaching process conditions of PST mainly include the extraction temperature,extraction time,and solid-liquid ratio and extraction times.First,Selecting the four factors in single factor experiment.On the basis of single factor experiment,then design L9(34)orthogonal table,orthogonal experiment was carried out.According to the result of orthogonal experiment,and comprehensive consideration such as degression and human factors,ultimately,selecting the optimal extracting technological conditions combination:extraction temperature is 90 ?,extraction time is 4 hours,extraction ratio of material liquid is 30 ml/g,extraction times is 2 times.Under this condition,the polysaccharide yield is 5.24%.2?The separation and purification,physical and chemical properties and preliminarystructure identification on PSTThe Crude PST Was separated and depurated by DEAE cellulose chromatography column and got three components PST-1,PST-2 and PST-3.Through determination,the results show that the the total sugar content of Crude PST?PST-1?PST-2 and PST-3 were 60.62%,73.16%,55.47%and 73.16%respectively.Protein content was 2.26%,1.06%,1.68%,2.26%respectively.Polyphenol content were 1.53,0.86,0.45,0.23(GAE mg/100 mg).Uronic acid content were 15.67%,9.83%,20.08%,18.76%,respectively.Sulfuric acid base content were 10.06%,8.56%,20.89%and 25.20%respectively.Using high performance liquid chromatography(HPLC)method for the determination of molecular weight and purity of PST-1,PST-2 and PST-3.Results showed that the molecular weight of PST-1,PST-2 and PST-3 were1372 KDa,1039 KDa,1127 KDa.respectively and three purified components of polysaccharide composition is more uniform.Using high-performance liquid chromatography(HPLC)and infrared spectroscopy for the preliminary analysis on the structure of Crude PST,PST-1 PST-2 and PST-3.The results showed that Crude PST,PST-1,PST-2 and PST-3 have the same monosaccharide composition,but the content is different.In Crude PST,the percentage composition of mannose,rhamnose,glucuronic acid,glucose,galactose,xylose and fucose were 19.85%,4.01%,2.63%,2.16%,20.45%,8.53%,38.14%.In PST-1,the percentage composition of mannose,rhamnose,glucuronic acid,glucose,galactose,xylose and fucose were 25.27%,3.11%,1.71%,3.11%,17.19%,5.23%,42.06%.In PST-2,the percentage composition of mannose,rhamnose,glucuronic acid,glucose,galactose,xylose and fucose were 20.11%,4.25%,7.33%,4.25%,14.50%,8.80%,38.03%.In PST-3,the percentage composition of mannose,rhamnose,glucuronic acid,glucose,galactose,xylose and fucose were 22.32%,22.32%,2.73%,2.76%,16.49%,4.56%,16.49%.Infrared spectrum detection results showed that Crude PST,PST-1,PST-2 and PST-3 all have the typical polysaccharide absorption peak in the range of 4000 cm-1-500 cm-1.3?The antioxidant activity and immunomodulatory activity of PSTThe antioxidant activity of crude PST and its three purified components,PST-1,PST-2 and PST-3 was tudied by chemical methods.The studies have shown that crude PST and its three purified components,PST-1,PST-2 and PST-3 all has a certain resilience and all can effectively remove the DPPH free radicals,superoxide anion free radicals,ABTS free radicals,and has a certain metal chelating ability.Crude PST and its purification components(PST-1,PST-2,PST-3)have certain proliferation effect on RAW264.7 cells,Can effectively enhance the ability of RAW264.7 cell to gobble up and the activity of acid phosphatase.4?In vitro digestion experiment of PSTBy study the digestion of crude PST in vitro saliva,gastric juice and gastrointestinal juice,the results show that after the digestion in saliva,gastric juice and gastrointestinal juice,the molecular weight of PST did not change obviously,reducing sugar content did not increase,and there is no monosaccharide released,fully show PST cannot be digested by saliva,gastric juice and gastrointestinal juice.