The Structure Characterization And Hypoglycemic Activity Analysis Of Polygonatum Odoratum And Polygonatum Yunnanensis Polysaccharides

Polygonati Rhizoma is one of famous Chinese edible medicinal plants,including Polygonatum sibiricum Red.,Polygonatum kingianum Coll.et Hemsl.and other species.At present,there are many studies on Polygonatum sibiricum polysaccharides(PSP),but few researches have been conducted on polysaccharides of Polygonatum kingianum(PKP).Screening active ingredients with hypoglycemic activity has become a focus of research into the use of edible medicinal plants.Comparative study on structural characterization and hypoglycemic activity of Polygonatum sibiricum from Shaanxi and Polygonatum kingianum from Yunnan were performed systematically.Polygonatum sibiricum polysaccharides and Polygonatum kingianum polysaccharides were extracted,and then their structure and hypoglycemic activities were analyzed in order to provide a scientific basis for the development and utilization of Polygonati RhizomaExtracts were identified as pure polysaccharides by evaluating the physical and chemical properties.The molecular weight was measured,PSP was 3.0×105 Da,PKP was 1.6×105 Da,and PSP was hardly soluble in water compared with PKP.Fourier transform infrared(FT-IR)analysis showed that both PSP and PKP have pyranoside bonds,which may be acidic polysaccharides.Circular dichroism(CD)analysis showed that PSP and PKP had obvious positive cotton effect at 210 and 220 nm,respectively,indicating that the solution molecules were entangled and coiled,and PSP had less curl structure than PKP.Congo red experiments showed that PSP,PKP plus Congo red complexes all were redshifted,PSP,PKP have a three-helix structure,PSP contains a smaller amount of triple helix structure than PKP.Scanning electron microscopy(SEM)observation showed that PSP mainly consisted of two kinds of microscopic morphology of multi-cell lamella structure and net chain structure,while the two microscopic morphologies of PKP included multi-cell lamella structure and multi-branched chain aggregation structure.Thermogravimetric analysis(TGA)showed that PSP is faster than PKP in the range of highest loss rate,and both PSP and PKP have strong thermal stability.Both PSP and PKP were not able to clear ABTS+·,DPPH·,and hydroxyl radicals(·OH).It was preliminarily determined that PSP and PKP had no in vitro antioxidant activity.Both PSP and PKP had no inhibitory effect on a-amylase,but they all had a certain of a-glucosidase inhibitory effect.The inhibitory effect of PSP was stronger than that of PKP.The half-inhibitory concentration(IC50)was 4.57 and 2.63 mg/mL,respectively.In vivo,the hypoglycemic test in streptozotocin(STZ)-induced diabetic mice by PSP was showed.By daily observation of mice,determination of food intake,water intake,body weight and blood glucose,we found that 600 mg/kg of PSP can make mice food intake,drinking water,blood sugar tend to be stable and have a downward trend,and the weight is slightly increased,which can effectively alleviate the symptoms of"three more and one less" in mice.According to the OGTT analysis,the PSP of 400 mg/kg and 600 mg/kg was significantly smaller than the model group(P<0.05).Compared with the model of mice,the ratio of PSP to 400 mg/kg and 600 mg/kg was significantly higher than that of the model group(P<0.01).The serum insulin(INS)and glycated serum protein(GSP)levels were determined in mice.600 mg/kg PSP can significantly increase the content of INS and decrease the serum GSP content(P<0.01).The INS content is 60.6115.56 mU/L.GSP content is 3.73±0.30 mg/mL.Hepatic glycogen analysis of mice showed that 600 mg/kg PSP can effectively promote the synthesis of hepatic glycogen.Through the activity.analysis of superoxide dismutase(SOD)and catalase(CAT)in liver of mice,600 mg/kg PSP can significantly increase the activity of SOD and CAT(P<0.01).The SOD activity of this group of mice was 113.63±15.54 U/mg prot,and the CAT activity of this group of mice was 59.25±7.33 U/mgprot.In summary,high doses of PSP can effectively alleviate organ damage,lower blood sugar,regulate blood sugar metabolism in the body,and alleviate diabetes.