Studies On The Ultrasonic-assisted Extraction Of Sulfated Polysaccharides From Eucheuma Striatum And Their Anti-oxidantion Activities

The thesis summarizes including two parts. One part, a comprehensive procedure for ultrasonic-assisted extracting active polysaccharides from Eucheuma striatum, a kind of big economical algae in South-China Sea, had been developed. The separation, physical and chemical properties of sulfated polysaccharides had been determined. The antioxidant activities of the polysaccharides was discussed. This conclusion could provide theoretical basis to the comprehensive development and utilization of marine algae resources. Another part is about the separating from the Petroleum ether fraction of Selaginella uncinata (Desv.) Spring.The ultrasonic-assisted extracting process of Sulfated polysaccharides from Eucheuma striatum was studied. One-factor experiment and orthogonal experiment were investigated. Extracting time had notable influence on the yield of polysaccarides. The optimum technology conditions were as follows: extracting with ultrasonic for 20min, ultrasonic power of 150w, dry material and water in a ratio of 1:90g/ml. With this optimum condition, the extraction ratio of polysaccharide is up to 48.14%, the polysaccharide content is 96.94% and the sulfate group content is 19.66%. Compared with the hot water extraction method, the extraction ratio of the polysaccharide, polysaccharide content and sulfate content extracted by the optimum technology are increased by 12.08%,8.07% and 1.41% respectively.The ESSP were separated by DEAE cellulose-52 column chromatography, then the polysaccharides had a further purification by Sephadrose CL-6B column chromatography. The pure products were named ESSP I and ESSP II. GPC results showed that molecular weight of ESSP I was 2.0114×106Da and ESSP II was 1.185x106Da. IR spectrograms showed that ESSP I and ESSP II had characteristic absorption peaks of polysaccharides.The anti-oxidation activities of the polysaccharides were studied by Fenton reaction and the self-oxidation of 1,2,3-phentriol. The results showed that the polysaccharides had better effects of elimination of O2·-, especially elimination of·OH. It was found that ESSP I was higher antioxidant activities than ESSP, and the role of polysaccharide concentration of activity with a dose-response relationship.The chemical constituents of Petroleum ether fraction of Selaginella uncinata (Desv.) Spring was isolated. Their structures were elucidated by spectroscopic analysis and comparison with published data. Four compounds were obtained and characterized to be physcion(1), erythroglaucin(2), friedelin(3),P-sitosterol(4). All of the compounds were isolated from this plant for the first time.