【作者】 钟洁；

【导师】 段玉峰；

【作者基本信息】 陕西师范大学 ， 农产品加工及贮藏工程， 2010， 硕士

【摘要】 蒲公英(Taraxacum mongolicum)别名婆婆丁、黄花三七、黄花地丁、奶汁草、黄花苔,属菊科多年生草本植物。全世界约2000种。我国有70种和1变种。营养丰富,药用价值高,现代药理研究表明,具有抗氧化、清热解毒等多种药用功效,还具有抗肿瘤、降血脂、免疫调节及抗氧自由基等作用。据《本草纲目》记载：“蒲公英嫩苗可食,生食治感染性疾病尤佳。”蒲公英有丰富的营养价值,20世纪初,国内外许多科研工作者开始对蒲公英中的化学成分进行研究,从中分离得到对羟基苯乙酸、咖啡酸、总黄酮、胆碱和甾醇、后来有文献相继报道了脂肪、碳水化合物也存在于蒲公英中,并进一步证实了黄酮类化合物、微量元素及维生素的存在等,本课题选取蒲公英为材料,采用现代分离分析技术对蒲公英糖蛋白组分进行了分离、纯化、结构表征的测定,以及理化性质的测定,并采用现代功能评价方法对蒲公英糖蛋白的粗提物和经过纯化后的三种纯品物质进行清除自由基能力和体外抗氧化活性试验,主要结论如下：1、采用热水浸提法提取蒲公英糖蛋白,正交试验得出最佳提取条件为：料液比1：20、浸提温度50℃、浸提时间5h、糖蛋白得率为4.82%。2、利用响应曲面法优化蒲公英糖蛋白的超声辅助提取,在单因素试验的基础上,通过响应曲面法建立了超声波辅助提取蒲公英糖蛋白的二次多项数学模型,得到的二次多项回归模型方程为：Y=5.25+0.26×A+0.36×B+0.43×C+0.35×D+0.14×A×B+0.25×A×C+0.082×A×D+0.023×B×C-0.15×B×D+0.14×C×D-1.04×A2-1.58×B2-1.35×C2-1.37×D2。3、利用响应曲面法得到的优化提取工艺参数为：超声时间20min、超声功率200W、水提取时间5h、水提取温度50℃。蒲公英糖蛋白的平均提取率为5.33%。4、蒲公英糖蛋白(TMGP)粗品经过DEAE-52分离得到的各组分分别经过采用SephadexG-100葡聚糖凝胶柱层析分离后得到：TMGP-a、TMGP-b、TMGP-c三种均一组分,采用薄层层析法对其纯度进行鉴定,结果显示三种成分均为均一组分。5、氨基酸自动分析结果表明蒲公英糖蛋白各组分里面均含有十几种氨基酸,如：天冬氨酸、谷氨酸、脯氨酸、甘氨酸、丙氨酸苯丙氨酸等。6、红外光谱分析结果表明,蒲公英糖蛋白三种均一品TMGP-a、b、c分别在3425cm-1、2922cm-1、1640cm-1、1352cm-1、1022cm-1附近都有吸收峰,这些区域的吸收峰都是多糖和蛋白分子的特征吸收峰；TMGP-b在1353cm-1、1273cm-1处的较弱的吸收峰分别是磺酰基和硫酸基中S=O的伸缩振动吸收,说明糖键可能是硫酸化多糖；在915cm-1、857cm-1、764cm-1处较弱的吸收,说明糖键中很有可能存在α-、β-糖苷键、β-D-半乳吡喃糖和α-D-葡萄糖。7、体外抗氧化实验结果表明,蒲公英糖蛋白粗品可以有效的清除DPPH·、O2-·和·OH自由基,具有较强的还原能力,并且可以有效抑制Fe2+诱导的脂质过氧化反应和β-胡萝卜素／亚油酸的自氧化,但在相同浓度下与BHT、抗坏血酸Vc比较其清除能力要比对照物的相应值低。但随着浓度的增大,其总还原力和对羟基自由基、超氧自由基及有机自由基的清除能力也随之增强,并且呈现出明显的剂量依赖关系。蒲公英糖蛋白均一品也可以有效的清除DPPH·、O2-·和·OH自由基,具有较强的还原能力。其中蒲公英糖蛋白均一品的效果较好,可能是该提取物中没有杂质。此外,蒲公英糖蛋白是否有较好的体内抗氧化活性,还有待进一步的实验研究。更多还原

【Abstract】 Dandelion (Taraxacum mongolicum.) has several aliases, for example:Flower seedlings、diluteyellow crotalaria herb、Flower Radix Notoginseg、huanghua moss,are all belong to Asteraceae, perennial and herbaceous plant.There are about 2000 species around the world,about 70 species in China and a variety.It contains nutrient-rich and high medicinal value.Modern pharmacological studies have shown that it has antioxidant,clearing heat and removing toxin and other medicinal effects,also has the function of anti-cancer,reducing blood pressure,immune regulation and anti-oxidation and so on.According to"Compendium of Materia Medica"records:Dandelion sprout is edible and the raw can be treated infectious diseases preferred. Dandelion is rich in nutritional value and it contains protein,fat,carbohydrates, microelements and vitamins,etc.In the present paper,we selected the material Dandelion,the composition of the glycoprotein form Taraxacum mongolicum has was isolated by modern separation techniques and purified,characterized by the determination of the structure,we use the methods of modern functional evaluation to study Dandelion crude glycoprotein and purified substances through scavenging free radicals capacity and raspberry vitro antioxidant activity,the primary results are as follows:1. The optimum conditions with the hot-water extraction method obtained by the orthogonal experiment design as follows:the ratio of sample to water is 1:20,the temperature is 50℃,the time is 5hours,Under the conditions,the extraction ratio of the glycoprotein is 5.09%.2. Using response surface method to optimize glycoprotein form Taraxacum mougolicum ultrasound-assisted extraction and resorting to Design-Expert7.1.6 software test design,on the base of the single-factor experiments,response surface method for the first time by ultrasonic assisted extraction of the two glycoprotein form Taraxacum mongolicum plays a number of mathematical models,quadratic regression equation:Y=5.25+0.26×A+0.36×B+0.43×C+0.35×D+0.14×A×B+0.25×A×C+0.08 2×A×D+0.023×B×C-0.15×B×D+0.14×C×D-1.04×A2-1.58×B2-1.35×C2-1.37×D2.3. The optimum conditions with the response surface method of process parameters as follows:ultrasonic time is 20min,ultrasonic power is 200W,water extraction time is 5h,water extraction temperature is 50℃.the average extraction rate of the glycoprotein form Taraxacum mongolicum has 5.33%.4. Three fractions named respectively TMGP-a,TMGP-b,TMGP-c is isolated and purified from the glycoprotein extracts by the DE-52 ion-exchange and Sephadex G-100 gel filtration chromatogram,the purity is identified by thin layper chromato graphy(TLC),and the results showed that three components are all homogeneous.5. Amino acids analysis show that Taraxacum mongolicum has glycoprotein contain almost all the essential amino acid required for the human body,as follows:Aspartic,glutamic,proline,glycine,alanine,phenylalanine are higher than others.6. Infrared spectroscopic analysis showed that glycoprotein form Taraxacum mongolicum has in the 3425cm-1,2922cm-1,1640cm-1,1352cm-1,1022cm-1have absorption peak,polysaccharide and protein are all charateristic absorption band in these regions.TMGP-b have absorbed weaked and the sulfate group in the sulfonyl S=O stretching vibration absorption in the 1353cm-1,1273cm-1,indicating sugar chain have sulfated polysaccharides,in915cm-1,857cm-1,764cm-1weak absorption,indicating the existence of sugar in the chain,includingα、βglycosidic bond,β-D-galactopyranosyl,α-D-glucose.7. The results of this text showed that glycoprotein form Taraxacum mongolicum has high antioxidant capacities It can effectively scavenge the DPPH·,peroxide anion,and hydroxyl radicals remarkably free radical,glycoprotein form Taraxacum mongolicum has also showed powerful inhibitory effects on peroxidation of polyunsaturated fatty acid from yolk lipoprotein induced by Fe2+ and onβ-carotene/linoleic acid assay system.But effective scavenging ability reducing power compare with BHT and Vc at the same concentration.However,as the concentration increased,the total reducing power and the hydroxyl radical,superoxide,and organic free radical scavenging ability have increased, showing a clear dose-effect relationship.pure glycoprotein form Taraxacum mongolicum has can effectively scavenge the DPPH·,peroxide anion,and hydroxyl radicals remarkably free radical,have strong antioxidant capacities It is better then glycoprotein form Taraxacum mongolicum has maybe clear pure glycoprotein.In addition,Whether there is more evident antioxidant activity of glycoprotein form Taraxacum mongolicum in vivo,it still needs further study.更多还原