| Portulaca oleracea L is the whole grass of Portulaca oleracea L , department of Portulaca oleracea L. It has important pharmacological activities. It can also be developed and utilized as a health product because of its rich nutritional ingredient. Polysaccharide has many pharmacological activities with no poisonous effect, it has been applied to clinical side and the market of health products widely. Portulaca oleracea L is distributed extensively in our country, and its resource is abundant. It has great potentiality to be exploited. In this paper, in order to probe undiscovered polysaccharides and their active functions, polysaccharide of Portulaca oleracea L is studied as our object..There are few reports on polysaccharide from Portulaca oleracea L, and they only involved the survey of its content and study on its antitumor function. The reports about its further separation, purification and pharmacology function are even less. In this thesis, we study mainly the extraction, separation, purification, components, properties of polysaccharides from Portulaca oleracea L, moreover, we also study their antioxidative activities.In this paper, we adopt traditional polysaccharide extraction method, that is being extracted by hot water, and precipitated by ethanol, then washed several times with 95% ethanol, 100% ethanol and acetone, at last, dried in vacuum at 50℃. The crude polysaccharide of Portulaca oleracea L obtained is light yellow. In the course of drawing, the effects of several main factors on extraction rate, e. g: volume of water, temperature, time and times of extraction have been investigated. Through orthogonal design, several main affecting factors and levels are discussed, and then the super condition of extraction is determined. The removal of protein in the product is compared by three different methods, Sevag method, TCA method and enzyme combined with Sevag method. The third method has its own obvious advantage. It may increase the removal rate of protein. At the same time, the loss rate of polysaccharides is reduced greatly. Enzyme can cut off the protein chain, then use classical chemical method (Sevag method) to deal with three times. The method is an ideal method for eliminating protein. Polysaccharide after removing protein is dialysed, we obtain part-pure product of polysaccharide-POL.POL is separated into three fractions (POL I , POL II and POL III) by DEAE-cellulose chromatography. Then they are purified by sephadex G-200 gelchromatography into POL I b, POL II a and POLIII' ,which are tested by gel filtration on sephadex G-200 and cellulose acetate pellicle electrophoresis. The result of electrophoresis assumes a single spot. There is a single symmetric peak respectively by gel filtration. The identification of purity implies that they are homogeneous components.Molecular weight of the polysaccharide is determined by gel filtration. The result indicates their average molecular weights are estimated to be 18kD, 56kD and 410kD respectively. Molecular weight of POLIII' is the maximum and the molecular weight of POL I b is the minimum .POL I b, POL II a and POLIII' are hydrolyzed by 2M sulphuric acid, then their component and structure are measured by means of GC. The result shows POL I b is composed of glucose and galactose with the molar ratio of 2.39:1.00. The component of POL II a is consisted of arabinose, xylose, fructose, mannitose, galactose and glucose in a molar ratio of 0.62:0.74:1.06:0.55:0.71:0.15. The main compositions of POLIII' are glucose and galactose, their molar ratio is 0.65:1.00. Typical absorption of nucleic acid or protein can not be observed in UV spectrum. POL I b, POL II a and POLIII' have typical characteristics absorption peaks of polysaccharides in their Infrared ray spectrum , which indicates a -glucosidal bond in POL I b and POL II a , β - glucesidal bond in POLIII' .The experiment studies antioxidative activities of four kinds of polysaccharides (POL,POL I b, POL II a and POLIII' )from Portulaca oleracea L, and analyses their effects of...
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