| 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.
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