Preparation Of Physalis Pubescens L.polysaccharides And Its Hyperglycemic Activities In STZ-induced Diabetes Mice

Physalis pubescens L.is an annual plant,which benlongs to Physalis Genus,Solanaceae.It is mainly distributed in Liaoning,Jilin,Heilongjian,Xinjiang and Hulunbeier et al.It has been reported that Physalis pubescens L.can be used for the treatment of diuretic,antibacterial,phlegm and antitussive.A t present,the research about polysaccharide of Physalis pubescens L.focuses on its extraction and purifying technology.There are few studies on structural characteristics,structure-activity relationship and biological activities of polysaccharides.In the present study,systematic studies on the isolation,purification,primary structure physicochemical property,hyperglycemic effects and the hyperglycemic mechanism of Physalis pubescens L.polysaccharide were carried out.The main results are as follows.(1)Polysaccharide was extracted from Physalis pubescens L.by hot water,the yield of polysaccharide was 5.32±0.45%.The content of total carbohydrate,protein,uronic acid,sulfated group and total phenols of Physalis pubescens L.Polysaccharide(PP)were 79.43±0.36%?1.49±0.20%?14.5±0.27%?6.82±0.42% and 0.96±0.09%,respectively.The molecular weight was 19959 Da,the number average molecular weight was 123174 Da,and the dispersion index was 1.38.Monosaccharide composition analysis indicated that PP was composed of rhamnose,arabinose,xylose,fucose,mannose,glucose and galactose,and the molar percentages was 5.73%?2.15%?0.68%?2.67%?83.04% and 5.75%,respectively.PP showed strong antioxidant activities,including DPPH radical scavenging activity,oxygen radical absorbance capacity and reducing power.In addition,PP exhibited strong inhibitory effects on ?-amylase activity.(2)The hypoglycemic effect of PP in STZ-induced diabetic mice was studied.The results showed that PP could improve the mental state,relieve the symptoms of polydipsia,polyphagia,polyuria and weigh loss,decrease blood glucose level and enhance glucose tolerance.Furthermore,PP could suppress enlargement of liver and kidney,and antagonize atrophy of thymus and spleen.It indicated that PP has hyperglycemic and immunoregulation activities.(3)The study on the influence of PP on glucolipid metabolism was carried out to clarify its hyperglycemic effect.The results showed that PP had significant effects against the increase of TC,TG,LDL-c and BUN,and the reduction of HDL-c,indicating that PP could improve the lipid metabolism and alleviate damage to kidney in STZ-induced diabetic mice.High dose of PP(800mg/kg/d)could obviously increase C-peptide levels and hepatic glycogen content,and improve GCK activity,which is one of t he key enzyme in sugar anaerobic glycolsis.PP could also decrease G-6-pase activity,thereby inhibiting gluconeogenic and glycogenolytic pathways.(4)The study on t he influence of PP on the antioxidant enzyme activities in diabetic mice was carried out to clarify its hyperglycemic effect.The results showed that PP had potential effects on reducing oxidative stress by decreasing the content of MDA,and increasing the activities of SOD,GSH-Px and CAT and the contents of VC and VE in diabetic mice,respectively.It indicated that PP could enhance the activities of antioxidant enzyme activities,and inhibit the over production of free radicals.(5)PP was extracted by hot water and fractionated by DEAE-Sepharose fast-flow chromatogram to obtained PP-1,PP-2 and PP-3.The physicochemical property,structural difference,antioxidant and hypoglycemic activities of the fractions in vitro were systematically studies.PP-1 exhibited comparatively higher antioxidant activity and stronger inhibitory effectagainst ?-amylase,than PP-2 and PP-3.Tertiary structure analysis indicated that PP-1,PP-2 and PP-3 had triple-helical conformation.The gas chromatography(GC)results showed that PP-1 contained arabinose(5.73%),xylose(0.68%),fucose(2.15%),mannose(2.67%),glucose(83.04%)and galactose(5.75%),both PP-2 and PP-3were composed of rhamnose,arabinose,xylose,fucose,mannose,glucose and galactose,showing the difference in monosaccharide contents.The IR analysis demonstrated that typical polysaccharide absorption peaks were shown in PP-1,PP-2 and PP-3.PP-1 and PP-2 contained furanoid ring,?-glycosidic bond and ?-glycosidic bond.PP-3 had ?-pyranose glycosidic bond connection.