The Preparation Of Sweet Potato Polysaccharide And Its Blood Sugar Lowering Effect In Vivo

Diabetes is an endocrine disease caused by absolute or relatively deficiency of insulin secretion and is seriously threatening human health.At present,the chemicals used to treat diabetes have a remarkable curative effect,but they cannot be eradicated from the cause,but also produce a series of side effects.Therefore,there is an urgent need to find clinically effective diabetes drugs with low toxic and side effect.Pachyrrhyizus erosus L.is a high-yielding economic crop with high protein content and low fat,and has good development value.The present study aims to study the Pachyrrhyizus erosus L.polysaccharides?PEP?activities that have the potential to treat diabetes and analyze the structural characteristics,so that to realize the high-value utilization of Pachyrrhyizus erosus L..The main contents of this study are as follows.1.In this study,the extraction parameters?temperature,extraction time and ratio of solid to liquid?of PEP were optimized by using the method of ultrasonic assisted extraction with hot water.And the optimal conditions:extraction temperature 75°C,extraction time 3h,solid-liquid ratio 1:20?w/v?,the yield of crude polysaccharide extraction rate under optimum conditions was 4.73%.2.Three kinds of PEP?PEP60,PEP80,and PEP95?were fractionated by ethanol fractionation with volume fractions of 60%,80%,and 95%respectively,and the extraction rates were 9.78%,45.11%and 10.15%,respectively.The results of in vitro antioxidant experiments showed that polysaccharides had the ability to scavenge hydroxyl radicals and ABTS⁺radicals,and also the scavenging ability was PEP95>PEP80>PEP60,in which the IC₅₀ values were 2.73mg/mL and 3.96mg/m L of PEP95,respectively?3.A mouse model of diabetes was induced by the combination of STZ and high-calorie diets.Multiple biochemical indicators were measured in experimental mice taking PEP,and the liver,kidney,and pancreas tissues were observed and analyzed,renal tissue was stained with PAS and TGF-?1 immunohistochemistry.The results show that PEP has a good antioxidant activity in vivo.This feature may play a role in regulating blood glucose levels in diabetic mice,reducing the mesangial matrix index and the expression of TGF-?1 in kidney tissue,and at the same time reducing oxidative damage and protecting the liver and kidneys.4.In order to further elucidate the relationship between the hypoglycemic and antioxidant activities of PEP with its structure,the PEP was isolated and purified to obtain a single polysaccharide component PEP95-DS,whose average molecular weight was 11.4 kDa,mainly composed of glucose,mannose,rhamnose,glucosamine,galacturonic acid,galactose,xylose,acarbose and other heteropolysaccharides and the UV absorption showed no nucleic acids and protein,the infrared scanning showed that it was a heteropolysaccharide.Meanwhile,in order to explore the relationship between the structure and functional activity of PEP,the hypoglycemic activity was studied.