Application Of The NMR Techniques In Structural Analysis Of Polysaccharides

The polysaccharides and proteoglycans extracted from G. lucidum could promote the release of serum insulin and decrease the plasma glucose level in vivo, we successfully isolated an bioactivity extract,named FYGL. FYGL may serve as a drug candidate or a health-care food for the diabetic therapy or protection. FYGL was a macromolecular complicated substance. For clarifying the structure-activity relationship,FYGL was further fractionated. Among them,FYGL-1was a novel neutral polysaccharide; FYGL-2was hypersaccharide-protein complex; FYGL-3was an acidic polysaccharide.Only the use of the chemical analysis methods such as Periodate oxidation, Smith degradation and methylation analysis cannot solve complicated molecules structure information, especially the linkage information between the suger residue. Here the detailed structure of FYGL-1,FTGL-2and FYGL-3were characterized by ID1H&13C NMR and2D NMR(gHSQC, HMBC, gNOESY, gCOSY&TOCSY), combined with chemicai analysis results. On the basis of ID1H&13C NMR and2D NMR, we can obtain the1H and13C chemical shifts of all residues. With the help of2D gHMBC and gNOESY, Inter-residue connectivities information can be determined.