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Dioscorea opposita Thunb. cv. Tiegun has been classified in the top grade of chinese yam for its good quality. Traditional Chinese medical science demonstrates that it promises to prevent cardiovascular disease and boost immune system. A series of research and experiments have been conducted to explore its chemical composition and action mechanism of its active ingredients.Firstly, the system pre-test method has been employed to detect the chemical composition in D. opposita Thunb. cv. Tiegun. Secondly, technology of polarity classification test has been performed to extract and separate allantoin. Thirdly, the methods such as alcohol reflux, column chromatography, chemical detection and UV detection have been applied to separate and verify the flavonoids, while the experimental management and data processing have been achieved in virtue of the so-called response surface method. Fourthly, Membrane filtration and column chromatography separation has been adopted to purify polysaccharides. Moreover, method of salicylic acid and pyrogallol autoxidation has been employed to evaluate the effect of polysaccharides and flavonoids in scavenging the activity for free radical.Our achievements lie in two aspects, experiment achievements and research achievements, respectively. With respect to the experiment achievements, they consist of the following two major parts, and the first one comes below:By the extract of D. opposita Thunb. cv. Tiegun, the discrimination reaction test demonstrates that the ingredients ranging from allantoin, phenolic compounds, flavonols, flavonoids, proteins, polysaccharides, saponins to lipid are positive. However, the ones such as organic and alkaloids hold negative. With respect to its white crystals from n-butanol saturated solution, IRvmaxcm-1 is:3440,3445,1783,1712,1657,1603,1520,1184,1011,817, 780,760,710. With respect to its flavonoids, UV absorption in the methanol solution shows that:areaⅠin 362nm, areaⅡin 259nm, and it’s chemical reaction is clear in 10 diagnosis test of flavonoid. With respect to protein, Rf is 0.31 in polyacrylamide gel electrophoresis. PolysaccharideⅠ, Rf is 0.47,0.57 in TLC analysis.. PolysaccharideⅡRf is 0.47,0.53,0.57 in TLC analysis. Furthermore, our experiments shows that, specifying the concentration of lmg/ml with regard to total flavonoids and total polysaccharides, the clearance rate of·OH is 74.55%,29.45%; NO2- clearance rate is 29.41%,39.79%; DPPH·radical clearance rate is 30.2%,41.65%; superoxide anion O- clearance rate is 18.31%,27.2%,respectively.Our second experiment achievements are more interesting, coming in the following, our experiments indicate that the extraction rate of flavonoids ranges from 0.31% to 0.88%, and the extraction rate of polysaccharides falls into 0.74%-2.28%. Upon the effects made by D101 resin to D. opposita Thunb.cv.Tiegun, its static adsorption capacity is15.3mg/g, and dynamic adsorption capacity is 12.6mg/g, and static elution rate is 94.7%, and dynamic elution rate is 91.2% for flavonoids. The recovery rate is 87.43% upon liquid and resin ratio in 5:1, and the recovery rate is 95.2% upon liquid and resin ratio in 10:1. Under the condition that decolorization rate is 70.19% in D101 resin, and 67.17% in AB-8 resin, NKA-9 resin is 62.63%., Recovery rate is 92.2% in virtue of ceramic membrane to purify polysaccharide. In birtue of ultrafiltration membrane bore diameter in 2000, polysaccharides transmittance is 51.3% and purity is 42.7%. Moreover, our results also consist of polysaccharides transmittance is 89.6% and purity is 33.8% with respect to ultrafiltration membrane bore diameter in 20000.Now we turn to our research achievements, which also include two major parts. With respect to the first part of research achievements, it indicates that D. opposita Thunb.cv.Tiegun contains a variety of major contents including allantoin, flavonols, flavonoids, proteins, polysaccharides, saponins and lipid chemicals. For the above mentioned ingredients, D. opposita Thunb. cv. Tiegun is poor in diosgenin,while is rich in allantoin reaching to 0.53%. With respect to flavonoids contents,3,5,7,3’-tetrahydroxy flavonols is compared rich. With respect to protein contents, simple protein with molecular weight of 22KD has been found. In polysaccharide, molecular weight less than 2000D accounts for 21.9%, and molecular weight between 2000D and 20000D accounts for 30.3%.Two pure polysaccharides is isolated, they are polysaccharideⅠand polysaccharideⅡ, respectively. PolysaccharideⅠis composed of glucose and sorbose; polysaccharideⅡis composed of glucose, sorbose and fructose. Hence, our research discloses that total flavonoids and total polysaccharides are effective in scavenging oxygen radicals, which play the fundamental role in boosting immune system and preventing cardiovascular disease.With respect to the second part of research achievements, it indicates that For extracting flavonoids, under the condition that solid liquid ratio 1:10,80% ethanol,82℃,4h, fitting equation Y=0.67+0.092 A+0.082 C+0.074 A2-0.15B2+0.056 C2+0.069 D2, the optimum extraction effects will be achieved, and the maximum extraction rate is 0.88% in theoretical manner, and the prediction error is 3.3%. With respect to the purification of flavonoids using D101 resin, the optimum will be achieved upon the following conditions:sample in water solution, with the speed of 1BV/h, the dynamic adsorption capacity of 12.6mg/g,70% ethanol elution, elution speed is 1BV/h, elution volume is 3BV, decolorization rate of D101 resin is 70.19%. Polysaccharides extraction condition:extraction solid to liquid ratio 1:15, 60℃,1.5h, the total extraction rate was 2.28%.Condition in purification polysaccharides using ceramic membrane:the concentration of pressure is 2.4bar and temperature is 30℃membrane flux is 3.69, recovery rate of polysaccharide is 92.2%. Dioscin extraction conditions:solid liquid ratio 1:10, using 95% ethanol extract 3 times, each time 2 hours. Allantoin is obtained by double extraction of alcohol.We have classified the application area of strength regarding to D. opposita Thunb.cv.Tiegun by conducting the research and experiments, also provided a reliable experimental evidence in extraction and separation about its chemical composition.
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