【作者】 王春霞；

【导师】 滕利荣；

【作者基本信息】 吉林大学 ， 生物工程（专业学位）， 2022， 硕士

【摘要】 薏苡仁是薏苡（Coix lachryma-jobi L）的干燥成熟种仁,富含多糖、萜类、黄酮类、甾醇类、生物碱及内酰胺类等多种活性成分,具有降血糖、抗氧化、保肝、增强免疫力等药理作用。目前,薏苡仁多糖的降血糖活性研究成为热点,但是对于薏苡仁多糖的体外降血糖活性研究甚少。本论文以贵州兴仁县的薏苡仁为原料,采用超声-微波协同提取法提取薏苡仁粗多糖,通过正交实验得到最佳提取工艺;经sevage法脱蛋白并利用DEAE-52纤维柱层析法进行分离纯化,得到纯化多糖后对其进行结构分析,最后对薏苡仁多糖的抗氧化和降血糖活性进行研究。具体研究结果如下:（1）超声-微波协同提取薏苡仁多糖最佳工艺:通过单因素和四因素三水平正交实验优化得到多糖最佳提取工艺条件为:超声功率250 W,微波功率250 W,提取温度70℃,提取时间45 min,料液比1:25 g/m L,此条件下多糖得率为8.71%。（2）薏苡仁多糖提取物组成成分分析:高效液相色谱分析结果表明薏苡仁多糖是由多种单糖组成的酸性杂多糖,这些单糖有葡萄糖（745.0728 mg/g）、半乳糖（3.5022 mg/g）、葡萄糖醛酸（1.6101 mg/g）、阿拉伯糖（1.2522 mg/g）、氨基葡萄糖（0.9175 mg/g）、甘露糖（0.8924 mg/g）、半乳糖醛酸（0.7084 mg/g）、甘露糖醛酸（0.2675 mg/g）、L-岩藻糖（0.1070 mg/g）。通过红外光谱在4000～500cm^-1区的多糖类物质特征吸收峰分析得知薏苡仁多糖是β-糖苷键构型。（3）薏苡仁多糖的抗氧化活性研究:薏苡仁多糖对自由基具有一定的清除能力;多糖浓度为8.0 mg/m L时,对DPPH·自由基、O₂^-·自由基、·OH自由基以及ABTS·自由基清除率分别达58.30%、20.87%、45.57%和38.94%。（4）薏苡仁多糖的降血糖活性研究:薏苡仁多糖可以显著抑制α-葡萄糖苷酶和α-淀粉酶的活性,提高胰岛素抵抗HepG2细胞的葡萄糖消耗能力,具有显著的降血糖活性。更多还原

【Abstract】 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.更多还原