Isolation And Purification Of Chondroitin Sulfate From Yak And Preliminary Research Of Its Biological Activity

Currently,chondrooitin sulfate(CS)is mainly extracted from the animal cartilage tissue such as cattle,pigs,sharks world-widely,and it has issues including a crude manufacturing process,a low purification rate,and a poor quality.Using yak cartilage tissue,the research optimized CS extraction and purifiction methods,and studied its biological acitivities involving the immune enhancement effect,the hypolipidemic function and the anticoagulant effect,in order to improving the further manufacturing technology and valuable utilization.The main tests and conclusions are as follows:1.Optimization of the CS extraction methods from yak.Utilizing the purity of CS as indicating index,three extraction methods were investigated including the dilute alkali-enzymatic hydrolysis method,the alkali salt-enzymatic hydrolysis method and the ultrasonic-assisted alkali salt-enzymatic hydrolysis method.By the signal factor menthod and the response surface methodology,the optimum conditions of ultrasonic-assisted alkali salt-enzymatic hydrolysis method were as follows:material ratio was lg:6.5ml,the lye concentration was 8%,the extraction time was 2.7h,Na+concentration was 2.5mol/L,extraction temperature was 40?,and the CS purity was 55.60%.Also,the optimal process of papain enzymatic hydrolysis of chitosan was determined:the enzymolysis tenperature was 36.5?,the enzymolysis pH was 6.9,the amount of enzyme was 1:829,the enzymolysis time was 1.5 h,and the average purity of CS was 71.60%.2.Optimization of the process for purifying yak CS by anion exchange.The optimal conditions were as fellows:the rate of adsorption amount of liquid and resin volume was 1:1,CS aqueous solution concentrationthe was 25mg/mL,adsorption velocity was 1.0 mL/min,the adsorption time was 70 min,the concentration of NaCl solution was 2.5 mol/L,desorption velocity was 1.0 mL/min,the amount of eluant and resin volume ratio was 5:l,the analysis time was 90 min,and the purity of CS was 82.77%.Sephadex G75 was selected to petriify CS again,and the purity of CS was 99.30%under this condition.3.The study of the bioactivities of CS.The immunologic enhancement of CS was studied.The results showed that a high dose of CS had a positive effect on serum hemolysin in mice,and the low,medium and high doses of CS increased the spleen index and thymus index which referred an intensive function towards the humoral immunity of mice.The study of hypoglycemic function of CS from yak was studied.The results showed that the levels of total cholesterol,triglyceride and low density lipoprotein in the blood of mice were decreased in the hyperlipidemia group after the intragastric administration with CS,and the high density lipoprotein was also increased,respectively.The study on the anticoagulant effect of CS extracted from yak cartilage showed that CS had a certain anticoagulant effect,but its effect was much lower than heparin.