Studies On Extraction, Composition Analysis And Rheological Property Of Glycoprotein From Cynomorium Songaricum Rupr.

A wide variety of glycoprotein with abundant biological activities are widely distributed in biological bodies.Studies have shown that polysaccharide chain plays an important role in stabilizing the tertiary structure of proteins,preventing protein hydrolysis,and enhancing immune adjustment,etc.It is also beneficial to cells recognition,tumor cells inhibiting,anti-oxidation,anti-aging,etc.In addition,it has broad prospects in developing new special drugs and functional food.In recent years,a lot of scientific research has been investigated in glycoprotein pharmacological effects and health care system,which has achieved a series of progress.Plant-original glycoprotein drugs are safe and reliable,with a weak side effect and other advantages.Cynomorium songaricum Rupr.(C.songaricum)is a little-investigated source of healthy food and used as traditional Chinese medicine with strong tonic effect.It is a widely known traditional kidney impotence medicine.Modern medicine research showed C.songaricum have antioxidant,immune system regulation,anti-diabetic,anti-virus,anti-hypoxia,anti-aging,laxative,promote reproductive system function and neurological protection and other physiological activities.These activities of glycoprotein are closely related to its structure,and it is important to study the structure and in that way explore the physiological mechanism and structure-activity relationships.In this paper,the extraction process of C.songaricum glycoprotein(CSG)was optimized by single factor experiments combined with response surface methodology(RSM)design.And the CSG was purified by Sephadex G-200 gel column chromatography.The FT-IR,GPC,GC-MS,SEM and amino acid composition analyzer was used to explore CSG-1 structure characterization,and the glycopeptide bond type was determined by ?-elimination reaction.The flow behavior,thixotropy and dynamic viscoelasticity of the dispersions were characterized by rheometer.It provided a certain application in food and pharmaceutical industry.This paper consists of three parts as follow:(1)As was determined by single factor experiment and response surface method.the optimum process parameters were obtained and described as follows: extraction temperature,extraction time and liquid to material ratio were 52 ?,4.2 h and 32:1,respectively.The extraction yield of CSG was 6.39±0.32 %.The result of FT-IR showed that the samples had the characteristic absorption peaks of protein and carbohydrate.The weight average molecular weight(Mw)of the crude CSG was 2.064×105,the number-average molecular weight(Mn)was 8.214×104,and the polydispersity(Mw/Mn)was 2.512.The dispersibility of the CSG showed it was a mixture.The results of GC-MS showed the monosaccharide type was xylose,mannose,glucose and galactose,with the molar ratio of 17.02:14.31:56.51:12.16.(2)After activated carbon decoloration of the crude glycoprotein,the isolated fraction of CSG-1 was obtained by Sephadex G-200 gel column.FT-IR was used to determine the radical composition.GC-MS results indicated that the CSG-1 was composed by Man,Glu and Gal with the molar ratio of 35.47:33.07:31.46.The molecular weight and polydispersity were determined by GPC.The Mw was 5.343×106,Mn was 3.203×106 and Mw/Mn was 1.668,which indicated that the molecular weight distribution of CSG-1 was more homogeneous than CSG.The results of amino acid composition analysis showed that CSG-1 was composed of 17 amino acids,aspartic acid?threonine?serine?glutamic acid?glycine?alanine?cystine?valine?methionine?isoleucine?leucine?tyrosine?phenylalanine?histidine?lysine?arginine and proline,with the ratio of 5.536:2.570:2.193:5.966:2.788:4.133:0.229:3.403:0.805:2.378:4.217:2.356:2.246:1.110:3.967:4.082:1.584.The ?-elimination reaction indicated that CSG-1 had an O-linked type glycopeptide bond.CSG-1 and CSG both had a lamellar structure.(3)The CSG dispersion exhibited concentration-dependence pseudoplastic fluid flow behavior,and could be described by both the combined Casson-Bingham and Herschel-Bulkley non-Newtonian fluid model.Its viscosity was affected by temperature,p H and the present of salts(type and concentration).CSG behaved a typical of “weak” viscoelastic gel-structure,and showed shear dependent properties even when concentration was low.Strain sweep,frequency weep and thermal stability analysis showed an interesting dynamic viscoelastic property.At present,there was no related report about the extraction process,structure characterization and rheological properties of CSG.In this paper,CSG-1 was purified from the plant C.songaricum,which was a traditional Chinese medicinal mainly distributed in northwest of China.The structure of CSG-1 was characterized,and the rheological properties of the dispersion system were studied.It provided a certain theoretical basis in food and pharmaceutical industry.