Extraction, Purification And Structure Identification Of α-glucosidase Inhibitor In Glycyrrhizins Uralensis Fisch

As people’s standard of living continues to improve, there is a rapid rise in the incidenceand costs of treatment of diabetes, which has become an increasingly serious public healthproblem. Since most of the diabetic patients cannot be cured permanently, they have tocontrol diabetes with diet strategy, the supplemental insulin and hypoglycemic drugs.Alpha-glucosidase inhibitors, a new type of oral hypoglycemic drugs, has been used as thepreferred drug for clinical treatment of type2diabetes and the type1diabetes since the1990’s. Of the available method for preparation of α-Glucosidase inhibitor, extraction ofα-Glucosidase inhibitor from plant materials showed to be the most attractive approach due tofewer side effects of the extracts compared to the synthesized medicine. In this dissertation,the extraction and purification of a-glucosidase inhibitor from Glycyrrhizins uralensis Fischwere explored in order to provide references for the extraction of α-glucosidase inhibitorsfrom new green natural plant.1Optimization of the extraction of α-Glucosidase inhibitor from Glycyrrhizins uralensisFischThe effects of some influential factors on extraction yield of α-Glucosidase inhibitor wereinvestigated. And then orthogonal designed was applied to optimize the extraction conditions.Results showed that the best extracting reagent was water and the optimum extractiontemperature, extraction time and ratio of solid to liquid were30℃,1h and1:10, respectively.Under these conditions, the yield of α-Glucosidase Inhibitor reached48.11%. The effects ofthe extraction parameters on α-Glucosidase yield were in order of extracting time>temperature>ratio of solid to liquid.2Purification of α-Glucosidase inhibitor from Glycyrrhizins uralensis Fisch bymacroporus resinAmong the tested nine kinds of resins，OU-2resin with high polarity showed thehighest dynamic and static adsorption performances. The results suggested that the polarity ofalpha-glucosidase inhibitors from Glycyrrhizins uralensis Fisch extract was strong. Theeffects of various factors on the absorption and desorption of macroporous resin wereinvestigated and the best purification conditions by OU-2macroporous resin were determined as: adsorption temperature30°c, pH value5.5, extracts-resin ratio of25:1, and ethanolconcentration70%; under which the α-glucosidase inhibitor was further purification and therate of enzyme inhibition was greatly enhanced.3Structural characterization of the purified α-glucosidase inhibitor in Glycyrrhizinsuralensis FischThe purified α-glucosidase inhibitor compounds was structurally identified using infraredspectrophotometry(IR), ultraviolet spectrophotometry (UV), mass spectrometry (MS), nuclearmagnetic resonance spectroscopy (NMR), liquid chromatography, gas chromatography andICP Spectrometer. The α-glucosidase inhibitory compounds extracted from Glycyrrhizinsuralensis Fisch was thus confirmed as an. HPLC analysis showed that the purity of thisisoflavonoid compound in the purified α-glucosidase inhibitor compounds was as high as99.43%.Isoflavonoids is the main active component of many Chinese herbal medicines, whichshows several biological properties, such as anti-tumor, antibiosis, spasmolytic, reducingblood fat content, resisting lipid peroxide and inhibiting helicobacter effects. Our researchreported, for the first time, that isoflavonoids in Glycyrrhizins uralensis Fisch also possessedα-glycosidase-inhibition activity. The findings presented here may promote the researches instructure-function relations of α-glycosidase inhibitor in Glycyrrhizins uralensis Fisch as wellas the value-added utilization of the Chinese herbal medicines. In addition, the researchesprovided a new rout for preparation of α-glycosidase inhibitors, which showed high socialsignificance.