Research In Separation And Structure Of Sulfated Polysaccharides From Three Kinds Of Grateloupia

Grateloupia is a macroalgae of Rhodophyta, which is widespread along our coast.It is edible and also can be used as a medicine with the effect of antipyreticdetoxification and helminthicide. Recent research has shown that polysaccharide ofGrateloupia can be developed into a potential drug for its biological activities such asanticoagulant, antitumor, antivirus and so on. In this thesis, several kinds ofpolysaccharides are obtained from Grateloupia setchellii kylin, GrateloupiaQingdaoensis and Grateloupia Turutruru by different kinds of extraction andpurification methods. The physico-chemical properties are determined by chemicaland modern instruments analysis techniques. Then two kind polysaccharides fromGrateloupia Truruturu are chosen for further purification and identifation. And theprimary structures of two purified polysaccharides GTC22and GTH42are finallydefined.Three kinds of dry algal powder are extracted by cool water, hot water and hot2%Na2CO3solution at80oC sequentially. Nine types of crude polysaccharides areobtained and named as GSC, GSH, GSA, GQC, GQH, GQA, GTC, GTH and GTArespectively. The physico-chemical properties of nine crude polysaccharides areanalyzed. The results show that monosaccharide composition of the polysaccharidesis mainly sulfated galactose. Except for GSC, glucose is also existed in all the eightcrude polysaccharides. While a small quality of glucuronic acid is found in GQC andGQH. inThe contents of sulfate ester are higher GTC and GSC,20.69%and20.85%respectively.The molecular weights of the polysaccharides are between316.9KD(GSH) and534.5KD(GQA). Furthermore, the IR spectra also supports that thepolysaccharides of Grateloupia are mainly composed of galactose linked with sulfate ester.The two polysaccharides GTC and GTH are purified by anion exchangechromatography Q-Sepharose Fast Flow. Seven types of polysaccharides fractions areobtained and named as GTC1, GTC2, GTC3, GTH1, GTH2, GTH3and GTH4,respectively. Then physico-chemical properties of the seven components includingtotal sugar and sulfated content, molecular weight and purity are determined. Theresults show that the total sugar contents of GTC2and GTH4are69.9%and59.9%,respectively, while sulfated contents are21.7%and22.8%. Then the GTC2andGTH4are further purified by Sephacryl S-400. The results show that the purifiedfractions GTC22and GTH42have a single symmetrical peak in their elution line, andtheir molecular weights are44KD and404.8KD, respectively.Finally, the primary strucrures of GTC22and GTH42are clarified throughdifferent chemical and spectroscopy methods including desulfuration, methylation, IR,NMR and GC-MS. The results show that the main configuration of GTC22andGTH42are both β, containing few α configuration. The conjunctions ofmonosaccharides are mainly1â†'3,1â†'4and1â†'3,4in GTC22and1â†'4in GTH42.The c sulfate ester is mainly linked at C6position.Through systematical study on separation, purification and structuralcharacterization study of the water soluble polysaccharides extracted fromGrateloupia, the primary structures of two purified polysaccharides GTC22andGTH42are defined. This research has laid a solid foundation for furtherstructural-activity study and also the medical usage of the polysaccharides fromGrateloupia.