Studies On The Extraction, Purification And Functional Activities Of Glycosaminoglycan From Bullacta Exarata

Glycosaminoglycans (GAGs) are structurally diverse linear polysaccharides, which are composed of repeating disaccharide units that consist of a hexosamine and a uronic acid. Glycosaminoglycans display a variety of important biological roles such as anticoagulation, antitumor and hypolipemic etc. Papers showed that marine organisms are rich in glycosaminoglycans. Bullacta exarata is a kind of medicinal marine organisms with great exploration potential. Pharmaceutical research and protective products development of Bullacta exarata have theoretical and practical significance which will make full use of marine resources. This study could accumulate basic materials for glycosaminoglycan of Bullacta exarata, as well as establish foundation for further development of bio-medicine.On the basis of single factor experiments, the extraction conditions of glycosaminoglycan from Bullacta exarata were optimized by using the Design expert7.0software and response surface analysis. Two quadratic polynomial models were obtained by analysis the relationship between three factors(liquid-solid ratio, enzyme dosage and enzymolysis time) and the glycosaminoglycan yield. The model can reflect the relationship between the factors and the response value. The optimal liquid-solid ratio, enzyme dosage and enzymolysis time were of2:1,0.80%and7.5h, respectively. Under these conditions, the theoretical yield of glycosaminoglycan is0.265%.The crude glycosaminoglycan was purified by removing proteins, pigments, inorganic salts and other impurities. The results showed:of the first purification obtained GAG-1, the recovery was47.75%, the content of glycosaminoglycan increase from21.50%to65.20%; of the second purification obtained GAG-2, the recovery was62.14%, the content of glycosaminoglycan increase from65.20%to90.82%.The research had investigated the UV absorption spectra and agarose gel electrophoresis of purified glycosaminoglycan. The results showed:the UV of purified glycosaminoglycan did not have obvious absorption peak around260nm and280nm which proved the contents of protein and nucleic acid were low. Agarose gel electrophoresis showed that compared with standard products, tail spots of the glycosaminoglycan from Bullacta exarata was visible spectrum, indicating that the types in the glycosaminoglycan uneven dispersion of one or more molecular weight.Main chemical compositions of glycosaminoglycan lrom Bullacxa txaraaa was took. Results showed that the glycosaminoglycan contained3.95%sulfate,25.83%glccuronic acid and14.19%glucosamine.Infrared absorption spectrum of glycosaminoglycan from Bullacta txarata was analysised. Results showed that the glycosaminoglycan contained structures of-OH(3400cmn1),-COO-(1639cm-1).-SO2(1421cm-1) and C-O-C(1023cm-1) etc. The free radical-scavenging activity, anticoagulation function and antitumor effect were studied. The results showed:the glycosaminoglycan from Bullacta exarata had certain scavenging effect on·OH but not O2. The glycosaminoglycan had anticoagulation function that could prolong PT,TT and APTT of New Zealand White Rabbit plasma significantly. The glycosaminoglycan also have certain anti-tumor activity which would strengthen significantly as the raising of glycosaminoglycan consistency.