| Coix seed is Coix lachryma-jobi L dry ripe kernel,rich in polysaccharides,terpenoids,flavonoids,sterols and alkaloids and other active ingredients,with hypoglycemic,antioxidant,liver protection,enhance immune function and other pharmacological effects.At present,the hypoglycemic activity of coix seed polysaccharide has become a hot spot,but there is little research on the hypoglycemic effect of coix seed in vitro.In this paper,coix seed from Xingren County,Guizhou Province was used as raw material,and the crude polysaccharide of coix seed was extracted by ultrasonic microwave synergistic extraction method.The optimum extraction process was obtained by orthogonal experiment;After deproteinization by sevage method and separation and purification by DEAE-52 fiber column chromatography,the purified polysaccharide was obtained,and its structure was identified to study the antioxidant and hypoglycemic activities of coix seed polysaccharide.Based on these researches,the main results are as follows:（1）The optimum extraction process of coix seed polysaccharide by ultrasonic and microwave:through single factor and four factor three-level orthogonal experiment,the optimum extraction conditions of polysaccharide are as follows:ultrasonic power 250 W,microwave power 250 W,extraction time 45 min,extraction temperature 70℃,liquid-material ratio 1:25 g/m L.With this condition,polysaccharide extraction rate was 8.71%.（2）Composition analysis of coix seed polysaccharide extract:the results of high performance liquid chromatography showed that coix seed polysaccharide was an acidic heteropolysaccharide composed of a variety of monosaccharides,including glucose（745.0728 mg/g）,galactose（3.5022 mg/g）,glucuronic acid（1.6101 mg/g）,arabinose（1.2522 mg/g）,glucosamine（0.9175 mg/g）,mannose（0.8924 mg/g）,galacturonic acid（0.7084 mg/g）,Mannuronic acid（0.2675 mg/g）,L-fucose（0.1070mg/g）.At the same time,through the analysis of the characteristic absorption peak of polysaccharides in the 4000～500 cm-1region of infrared spectrum,it is known that coix seed polysaccharide isβ-Glycosidic bond configuration.（3）Study on antioxidant activity of coix seed polysaccharide:coix seed polysaccharide has certain free radical scavenging ability.When the concentration is8.0 mg/ml,the scavenging rates of DPPH·free radical,·OH free radical,O2-·and ABTS·free radical are 58.30%,20.87%,45.57%and 38.94%respectively.（4）Study on hypoglycemic activity of coix seed polysaccharide:coix seed polysaccharide can significantly inhibitα-Glucosidase andα-Amylase activity can improve the glucose consumption ability of HepG2 cells in insulin resistance model,and has significant hypoglycemic activity. |
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