Purification, Structural Characterization And Biological Activities Of A Polysaccharide From Elaeagnusangustifolial

With Elaeagnusangustifolia L as raw materials, the purification, structure, antioxidant activity, antitumor activity and anti-hyperlipidemia activity of the crude polysaccharide extracted from Elaeagnusangustifolia L were investigated in this paper. The results were as follows:(1) The crude EAP was extracted with hot water at 80℃ for 2h, repeated 2 times with a ratio of 1:35 (materials:water). The yield was 5.9% under the conditions.(2) The crude EAP was applied to a DEAE-52 cellulose column equilibrated with distilled water, which was fractionated three different fractions named EAP-1,EAP-2 and EAP-3. The main fraction EAP-1 was concentrated to obtain and then fractionated by size-exclusion chromatography on a SephaedxG-100 column, which generated main fraction named EAP-1 a. EAP-1 a was identified to be a homogeneous polysaccharide by using HPLC and gel filtration chromatography.(3) GC results showed that EAP-la was composed of rhamnose, arabinose, xylose, mannose, glucose, galactose at a molar ratio of 0.029:0.74:0.51:0.039:1.0:5.19. The molecular weight of EAP-la was 61421 Da determined by HPLC.(4) Infrared (IR) spectroscopy and nuclear magnetic resonance (NMR) spectrscopy were used to determine the configuration of EAP-la. The result showed that EAP-la was a kind of pyranose polysaccharides and α-configuration.β-elimination test indicated that long side chain and more branches may be existed in EAP-1a. CD analysis and Congo Red test of polysaccharide indicated that polysaccharide can complex with Congo Red, had a (+) cotton effect which showed that EAP-la could exist in triple helix structure in aqueous solution.(5) The result of antioxidant activity of polysaccharides from Elaeagnusangustifolia L showed that the crude polysaccharides with strong reducing power, at the same concentration conditions, the antioxidant activity of crude polysaccharides was investigated by using DPPH, hydroxyl radical and superoxide radical assay systems, The clearance rate of hydroxyl radical, superoxide radical and DPPH was up to 59%,21%　and 40%　at most.(6) The result MTT test resultsof polysaccharides from Elaeagnusangustifolia L showedthat polysaccharides from Elaeagnusangustifolia L could inhibit the proliferation of HepG2 cells at a certain extent, and calculate the processing time of cells for 48 h, of HepG2 cells half inhibitory concentration (IC50) was469μg/ml. Obvious changes in the cell morphology were observed by HE and Hoechst 33342 staining under the concentration of IC50 (469μg/ml) from the crude polysaccharide from Elaeagnusangustifolia L, which indicated that has antitumor activity.(7) The TC, TG and LDL-C in serum were lower than those of high fat control group while HDL-C were higher than that of the high fat control group after treated by oral administration with different concentrations of the crude polysaccharides, at the same time, AI was also decreased. These results indicated that the crude polysaccharide from Elaeagnusangustifolia L could adjust the blood lipid level to prevent hyperlipidemia.