Isolation,Purification,Structural Characterization And Bioactivities Of Polysaccharides From Fruits Of Psidium Guajava Linn And Humulus Lupulus

In our preliminary experiments and literature studies,we found the guava fruits polysaccharides possess extremely anti-diabetic effect on Type 2 diabetes mellitus(T2DM)and the Humulus lupulu polysaccharides have significant anti-osteoporosis effects.In this article,we firtstly evaluated the anti-diabetes on T2 DM rats and clarified the possible mechanism.Secondly,we systematically investigated the extraction,isolation,purification and characterization of Humulus lupulu polysaccharides.The guava polysaccharides(GP-1,GP-2,GP-3,GP-4)were obtained by hot water extraction,alkali extraction and ethonal precipitacion,removing proteins by sevag method,dialyzation with distilled water and lyophilization.In addition,the anti-diabetes effects on T2 DM of guava polysaccharides were evaluated.A method of high-fat diet and low-dose STZ injection was employed and successfully obtained a type 2 diabetic rat model.For clarifying the detailed effects,the fasting blood levels(FBG),oral glucose tolerance test(OGTT),insulin level(INS),insulin sensitivity index(ISI),C-Peptide level,free fatty acids(FFA),TC,TG,HDL-c,ALT,AST,pathological observation,anti-oxidant activities and insulin signaling pathway were measured.As a result,three polysaccharides(GP-1,GP-3 and GP-4)with significant anti-diabetic effets were recealed.The results suggested the polysaccharides could significantly decreased and efficiently control the FBG level in wweeks,which was consistent with the GSP results.In addition,guava polysaccharides significantly decreased INS,HOMA-IR,C-Peptide levels,indicating the polysaccharides can inprove the insulin sensitivities,thereby alleviating insulin resistance.Study has reported hyperlipemia is the vital factor for insulin resistance.The results showed the polysaccharides can significantly reduce the TC,TG,FFA levels,suggesting that guava polysaccharides can enhance the glycolysis process,strengthen glucose transport and utilization,thereby reducing the glucose level.Moreover,guava polysaccharides reduced the phosphorylation of IRS,enhance the expressions of Ins R,IRS-2,PI3 K,Akt and Glut4,strengthen the glycometabolism process,which were correlated with the results of up-regulated the expressions of insulin signaling pathway.Last but not least,guava polysaccharides inhibited the islet cell apoptosis.Therefore,it lower the secretion of islet ? cells.The anti-oxidant results demonstrated guva polysaccharides can improve the activity of CAT,SOD,GSH and GSH-Px,restoring the injury of oxidant effects on liver and islet cells,similar with the results of AST and ALT.Tanke all the results into consideration,we can fianally conclude that GP-1,GP-3 and GP-4 posses remarkable anti-diabetic effects on T2 DM rats and via anti-oxidant activities and PI3K/Akt signaling pathway.The Humulus lupulu polysaccharides(HLP50,HLP70,HLP90 and HLPB)were obtained by hot water extraction,alkali extraction and ethonal precipitacion,removing proteins by sevag method,dialyzation with distilled water and lyophilization.The polysaccharides were purified by DEAE-52 and Sephacryl S-100 gel-filtration column and then successively elucidated their structural conformation and microstructures by HPGPC,IR,UV,HPLC,NMR,SEM,AFM,CD analysis and chemical methods.And their sugar contents were estimated as 70.4%,64.31%,58.71% and 35.2%.HLP70 and HLP90 were successively purified by DEAE-52 and Sephacryl S-100 gel-filtration column.The homogeneous distribution and relative moleculars of HL70-2 and HL90-1 was performed by HPGPC and UV assays,the results desmonstrating that two purified polysaccharides were all homngeneous polysaccharides and the relative moleculars were 6505 Da and 2344 Da,respectively.Moreover,their structural characterizations were elucidated by a monosaccharides composition analysis,IR spectroscopy,methylation,GC-MS assay and 1D,2D NMR analysis.The results indicate that HL70-2 was composed of terminal ?-D-Glcp,(1?3)-linked-?-L-Araf,(1?2,3,5)-linked-?-L-Araf,(1?3)-linked-?-L-Rhap,(1?3,6)-linked-?-D-Manp and(1?6)-linked-?-D-Galp.HL90-1 was composed of terminal ?-D-Glcp,(1?6)-linked-?-D-Glcp,(1?4)-linked-?-D-Glcp,(1?4,6)-linked-?-D-Glcp,(1?3)-linked-?-L-Rhap and(1?3,6)-linked-?-D-Manp.And the two posaccharides were all structural characterized.In addition,the microstructural information chan conformation changes were inspected by scanning electron mircroscope(SEM),atomic force microscope(AFM)and circular dichroism spectroscopy(CD).