Studies On The Extraction, Isolation And Preliminary Analysis Of Selenium Polysaccharide In Natural Selenium-rich Plants

Both polysaccharide and selenium have the function of preventing and treating many diseases. The research about the activities of polysaccharide and selenium have been performed deeply. But it still stays at the primary stage in the world to combine the poly--saccharide and selenium into selenium polysaccharide organically. Selenium polysaccharide in natural selenium-rich plants has many advantages, such as high absorption and utilization ratio, safety and nontoxicity. It is highly concerned nowadays. This article summarized extraction, separation, purification, identification and physiological activity of plant polysaccharide and selenium polysaccharide. The main research contents and conclusions are as follows:1. The natural selenium-rich plants, pumpkin, konjac, gynostemma pentaphyllam makino, Jerusalem artichoke, ophiopogon japonicus, were chosen as primary material to extract crude polysaccharide, determine the content of selenium and polysaccharide. The results showed that the content of selenium in pumpkin was higher than in others. The content of selenium in pumpkin sample was 19.48ug/g, and polysaccharide was 11.6%. So the pumpkin was selected to research further.2. Making a standard of evaluation by the extraction percent of polysaccharide, single factor and orthogonal test were applied to analyze the effect of factors, such as solid-liquid ratio, temperature, time and times on the extraction percent of selenium polysaccharide in pumpkin extracted by hot-water. The results showed that temperature was the most important factor, solid-liquid ratio was the second, and time was the least. The optimum technological conditions of extraction were as follows: ratio of solid-liquid 1:20, 70°C for lh and 2 times extraction. The extraction percent of polysaccharide was 2.790% and selenium was 20.21ug/g on the optimum conditions.3. Selenium polysaccharide in pumpkin was isolated and purified by removing of its impurities in refluxing with methanoi, extracting by hot-water, centrifugating, deproteinizing according to the method of Sevage, dialyzing, depositing with ethanol repeatedly, and freeze-drying in vacuo. White and khaki, granulated samples were obtained. Their physical and chemical characters were studied, and structures were analyzed by IR (Infra-Red) and Raman spectra. The results showed that both of their spectrograms were superposedcompletely, and there were typical characteristic absorption peaks of polysaccharide. It was testified that the two color samples were polysaccharide. The content of selenium and polysaccharide was 46.08ug/g, 33.7% respectively.4. The sample was graded further by Sephadex G-100, Sephadex G-200 gel chromato--graph. Two components were obtained from Sephadex G-200, and their structures were analyzed by UV (Ultraviolet-Visible) and CD (Circular Dichroism) spectra. Component I was studied further by IR spectrum. The results showed that glucose was a dominant monosaccharide in component I.