Study On The Structure Characterization And Biological Activity Of Sulfated Modified Jujube Polysaccharide

In order to further study the relationship between the structure and biological activity of the purified red jujube polysaccharide and the sulfation modification product,this paper uses the red jujube crude polysaccharide(ZJP)as the experimental raw material,DEAE-52 ion exchange chromatography and Sephadex-200 dextran gel column layer Analyze and purified by Sephadex-200 dextran gel column chromatography to obtain purified jujube polysaccharide(ZJP-1-1).The sulfated red jujube polysaccharide(S-ZJP-1-1)was prepared by concentrated sulfuric acid method,explore the structure and biological activity of ZJP-1-1 and S-ZJP-1-1The results are as follows:1.Separation,purification and structural characterization of jujube polysaccharidesUsing the purchased jujube crude polysaccharide(ZJP)as the main raw material,The best methods for ZJP decolorization by activated carbon adsorption decolorization method,H2O2 decolorization method and two macroporous resin(AB-8 and D101)decolorization methods were screened out,as well as the best deproteinization times with Svage reagent.The results show that Using the Sevag method to deproteinize 6times has the best effect on ZJP deproteinization,and the polysaccharide retention rate is relatively high,the deproteinization rate is 74.53%,and the retention rate is 70.87%.Among the decolorization methods,the macroporous resin AB-8 has the best decolorization effect,and the polysaccharide retention rate is higher,the decolorization rate is 83.1%,and the polysaccharide retention rate is 72.81%.The preliminarily processed red jujube polysaccharides were subjected to DEAE-52 column chromatography to obtain four main components,ZJP-1,ZJP-2,ZJP-3 and ZJP-4.Through the determination of the antioxidant activity of the four components of polysaccharides.The ZJP-1 with the highest oxidation activity is subjected to Sephadex G-200 column chromatography to obtain the polysaccharide ZJP-1-1.The purified component is light yellow powder,without starch,polyphenols and reducing sugars etc.;The purified red jujube polysaccharide ZJP-1-1 is a heteropolysaccharide with a Mw of 4.937×104 Da,composed of glucose,arabinose,and galactose,with a molar ratio of 99.328:0.449:0.411.ZJP-1-1 has an α-pyran A polysaccharide with a triple helix structure composed mainly of sugars.It has many branches.The main chain has 1→6,a small amount of 1→3,1→2 and 1→4 linked glycosidic bonds,.Under the scanning electron microscope,it is an irregular flake shape and has a certain thermal stability.2.Sulfation modification and structural characterization of jujube polysaccharidesUsing concentrated sulfuric acid method to sulfation modification of red jujube polysaccharide,the best conditions obtained by single factor test are: the ratio of esterification reagent(concentrated sulfuric acid: n-butanol)is 3:1,the reaction time is 0.5 h,and the reaction temperature is At 0℃,the degree of substitution of sulfated jujube polysaccharides is the highest.the sulfated derivative of jujube polysaccharide S-ZJP-1-1 was obtained according to the optimal reaction conditions.S-ZJP-1-1 is a heteropolysaccharide with Mw of 2.482×105 Da,composed of glucose(Glc),arabinose(Ara),and galactose(Gla).The molar ratio is 74.046:0.232:0.288,of which FT-IR analysis S-ZJP-1-1 not only has the absorption peak of polysaccharide,but also has the characteristic absorption peak of sulfuric acid group,indicating that the sulfation modification of jujube polysaccharide was successfully carried out.Nuclear magnetic resonance spectroscopy,periodic acid oxidation,Congo red test,etc.show that S-ZJP-1-1 has the same main chain structure as ZJP-1-1,does not have a triple helix structure,and the surface is relatively smooth and irregular sheet-like morphology,the thermal stability is relatively improved.3.Analysis of biological activity of jujube polysaccharidesAfter testing the antioxidant activity of ZJP-1-1 and S-ZJP-1-1,the results show that both of them have good antioxidant properties.When the sample concentration is 0.5mg/m L,the DPPH free radical scavenging activities of ZJP-1-1 and S-ZJP-1-1 are 40.4% and 47.6%,and the free radical scavenging activities of ATBS are 42.02% and 43.53%.The OH scavenging rate reached 43.02% and 46.53%,the superoxide anion radical scavenging activity was 39.55% and 42.77%,the reducing power was 0.419 and 0.531,and the Fe2+chelating activity was 39.55% and 44.77%.The glycosidase inhibitory activity of ZJP-1-1 and S-ZJP-1-1 was measured,and the results showed that both have good glycosidase inhibitory ability.When the polysaccharide concentration is 0.5mg/m L,ZJP-1-1 has 71.34% of α-glucosidase and 81.47% of α-amylase inhibition rate,and S-ZJP-1-1 has 78.12% of α-glucosidase.and the inhibition rate of α-amylase was 84.34%.In summary,sulfated red jujube polysaccharide S-ZJP-1-1 has stronger in vitro antioxidant capacity than purified polysaccharide ZJP-1-1,and its glycosidase inhibitory capacity is also higher.