Study On Extraction, Purification And Biological Activity Of Fistular Onion Stalk(Allium Schoenoprasum L.)Polysaccharides

Chievs is a kind of popular condiment and vegetable in China. It belongs to amaryllidaceae allium and it is a kind of perennial ratoon herb. Fistular onion stalk is the bulb of chievs. It contains polysaccharides which has not been developed and utilized home and abroad so far. The dissertation studied the water extraction of fistular onion stalk polysaccharides(FOSP) and optimized the extraction technology. Then the polysaccharides were separated and purified and the structure characterization and functional properties of reducing lipid and antioxidation were studied. The main experiment contents as follows:(1) The water extraction technology of FOSP was optimized by response surface analysis. The effects of extraction temperature, extraction time and ratio of material to water on the extraction rate were studied. The experimental results showed that the order of different factors affecting extraction rate was extraction temperature, ratio of material to water, extraction time. The optimal experimental parameters were:83.35℃extraction temperature,1:32.7of ratio of material to water,2.57h/once of extraction time. On this condition, extracting twice, the extraction rate of polysaccharides could be15.98%.(2) A high performance liquid chromatography(HPLC) method with pre-column derivatization was established for the determination of the monosaccharides of FOSP from the processing wastes in Xinhua and their molar ratio. The results showed that FOSP were composed of mannose, glucose, galactose and arabinose and their molar ratio was about1.0:31.5:22.6:5.1.(3)The polysaccharides were separated by Sephadex G-150column chromatography after depectinization, dialysis. Two symmetric peaks were obtained. The components from second peak were homogeneous by ultraviolet scanning and HPLC identification. The relative molecular weight was about5195dalton by HPLC. Structural determination of polysaccharides by IR and NMR.(4) In this paper we studied the effects of FOSP on blood lipid and their preventive effects on alcoholic liver. In the function test of reducing blood lipid, the wistar rats were divided into six groups:three control groups, low dose group (100mg/kg-BW), middle dose group (200mg/kg-BW), high dose group (400mg/kg-BW). After continuously feeding to rats for30days, tail blood was taken to determine the content of TC, TG and HDL-C. The results showed that the effect of reducing blood lipid of polysaccharides was better than Xuezhikang capsule. The high dose group could reduce TG significantly but TC not significantly; Every dose group could increase HDL-C significantly. In the test of the preventive effect of alcoholic liver, the mice were divided into six groups the same as above. Continuously feeding to mice for30days, we determine the content of MDA, TG and GSH. The results showed that the preventive effect of of polysaccharides on alcoholic liver was worse than Silymarin; The high dose group could reduce TG significantly and increase GSH significantly; Every group could reduce MDA significantly. From these results we drew the conclusion that FOSP could reduce blood lipids of wistar rats but the preventive effect on alcoholic liver was weak.(5) Vitro antioxidation activity of the FOSP was evaluated by OH, O2-· and DPPH(1,1-Diphenyl-2-picrylhydrazyl radical2,2-Diphenyl-1-(2,4,6-trinitrophe-nyl)hydrazyl) free radicals scavenging method comparing with ascorbic acid. The FOSP had powerful scavenging efficiency to-OH free radical, DPPH free radical and had dependent relationship with concentration. The scavenging activity of the polysaccharides to O2-· free radical was not good and did not have obvious dependent relationship with concentration.