Structure Characterization And Hypoglycemic Activit Of A Polysaccharide Isolated From The Root Of Pseudostellaria Heterophylla

TZS is one of traditional Chinese medicine with common widely use,TZS is the root of Psudostellaria heterophylla (Miq.) Pax ex Pax et Hoffm.2010edition of China pharmacopoeia recorded, TZS possesses nourishing qi to invigorate spleen, promoting fluid production to nourish lung. In clinical it commonly used in the treatment of diabetes combinations with other Chinses medicine.Modern pharmacological studies have shown that TZS total polysaccharides can lower blood sugar, improve insulin resistance, impaired glucose tolerance, improve immune effects.In the previous studies, the researches in most cases pitched at crue polysaccharide, Further structural studies of TZS polysaccharide has not yet been reported. Experiment shown that different molecular weight of polysaccharide has diffeent structure and hypoglycemic activity.This topic using glucose, insulin etc. as index to evaluate antidiabetic activity of TZS polysaccharides classified with ethanol; characterizing the structure of the most effective fraction to the treatment of type2diabetes.The paper is divided into four chapters, the main content of each chapter is as follows: The first chapter:TZS polysaccharides preparation and ethanol classification and molecular weight determinationThe polysaccharide was extracted by water and alcohol precipitation method.The crude polysaccharide fluid was deproteinized by Sevage method. Different concentrations ethanol graded ethanol precipitation to obtain four components named PH-TP、PF40、PF60、PF90,polysaccharide yields were7.2%、1.41%、2.89%、1.60%; phenol-sulfuric acid method and Coomassie brilliant blue assay the content of total sugar and protein of PHPs were41.08～47.28%and0.17～0.25%.Gel chromatography and different molecular weight dextran as a standard, eluted with0.5mol/LNaCl.The molecular weight distribution of PH-TP, PF40, PF60, PF90were3.0×103～2.1×105Da,5.2×104～2.1×105Da,1.0×104～2.1×105Da,3.0×103～7.0×103Da. The second chapter:TZS polysaccharides antidiabetic pharmacodynamic experimentsUsing a single tail vein injection of alloxan method for preparing a mice model of type1diabetes, metformin hydrochloride as a positive control; throughout the experimental period, the model mice maintain high blood sugar stable, self-healing is not obvious. PH-TP, PF40, PF60, PF90polysaccharide according to high, medium and low dose group (4,2,1g/kg) administered orally administered15d and30d, fasting blood glucose values. Administered15d, compared with the model group, PF40, PF60, PF90mice decreased fasting blood glucose value19.16%-25.81%, PH-TP group hypoglycemic efficacy obvious, positive control group mean blood glucose decreased60.11%. Increased administration time,30d fasting blood glucose was measured in each group, compared with the model group, positive control group mean blood glucose decreased75.58%; PH-TP, PF40, PF60, PF90group with extended delivery time, reduce the tendency of blood glucose and no increase; only weak hypoglycemic effect of polysaccharide levels in type1diabetic mice Taizishen.Using high-sugar high-fat diet feeding plus intraperitoneal injection of streptozotocin (STZ) method of type2diabetic rat model was prepared to metformin hydrochloride as a positive control; throughout the experimental period, the model rats maintain high blood sugar stable, self-healing not obvious. PH-TP, PF40, PF60, PF90according to high, medium and low dose (3.0,1.5,0.5g/kg) administered15d and30d. Administration15d, compared with the model group, showing a slight hypoglycemic effect; administered30d, compared with the model group, PH-TP, PF40, PF60, PF90set its hypoglycemic effect is remarkable; PF40(molecular weight of5.2x104~2.1x105Da) hypoglycemic effect is particularly significant,3.0g/kg high dose group and positive control equivalent to the average blood glucose decreased72.99%.PF40polysaccharide fractions can improve type2diabetes, impaired glucose tolerance and insulin resistance in rats, can reduce serum insulin, improved insulin resistance. Determination of type2diabetic rats associated markers (CRP, ACRP-30, IL10,Leptin, IL1β, TNFa, IL2), the results showed that the polysaccharide fractions PF40can enhance anti-inflammatory cytokine IL-10levels, lower levels of inflammatory cytokines TNF-a enhance ACRP-30, promote fat metabolism, but CRP, Leptin, IL-1β, IL2levels were not significantly affected. Meanwhile, the component also slightly elevated high-density lipoprotein (HDL) effect.The third chapten:Purification and structure characterization of PF40polysaccharidesUsing DEAE-cellulose combine with different exclusion ranges of Sephacryl, Sephadex gel got seven homogeneous polysaccharides from PF40; application HPLC, GC-MS, NMR, elemental analysis, polarimetry, IR and other technical methods to characterize the primary structure of two homogeneous components.The main chains of H-1-2was composed of (1->4)-linked-glucopyranosyls,and side chains were singlea-glucopyranosyl residues attached to the O-6of glucosyls in the main, also a small amount of (1->6)-linkeda-glucopyranosyls in the side chains. The main chains of N-3was composed of (1->4)-linked-a-D-GalpA residues,and a small amount of RG I structure combined with the main chains. Some glucan heterozygous inside the N-1homogeneous polysaccharides.The fourth chapter:summary and prospectThis research found that the molecular weight of50kDa-210kDa TZS polysaccharides reduce fasting blood glucose in type2diabetic rats effect is particularly significant, can effectively reduce serum insulin, improved insulin resistance, but also can increase the level of anti-inflammatory cytokines IL-10, reduces proinflammatory cytokine TNF-α, enhance ACRP-30cytokine levels, and can even enhance the role of HDL levels; this fraction is mainly composed of a-glucan and pectin two polysaccharides.Diabetes is a chronic disease, patients needs long-term treatments in order to have their conditions brought under control and to prevent complications, the side effects of chemical drugs on the human body is difficult to overcome; polysaccharide is one of the four basic substance of life,in recent years many polysaccharides have been reported to reduce blood sugar, improve diabetes symptoms efficacy, polysaccharides as a potential antidiabetic drugs has become increasingly widespread attention.50kDa~210kDa molecular weight of TZS polysaccharides has significant hypoglycemic effect, and it is a promising anti-diabetic substance that will be helpful for the treatment of T2DM.