Isolation,Purification And Immunostimulatory Activity Of Polysaccharides Derived From Root Of Apios Americana Medikus

Root of Apios americana Medikus was used as the raw material in this study. A.americana Medikus polysaccharides were purificated by water extraction, protein removal, pigment removal,ethanol precipitation and lyophilization. MP1, MP2, MP3, MP4 and MP1-1 were got from crude polysaccharides, which were further purified by DEAE-52 cellulose and Sephadex G-100 chromatography. Then used HPLC, GPC, NMR and FT-IR to detect the relative molecular weight,polysaccharides composition and structure of the five polysaccharide fractions. The activity of polysaccharides were tested by the Influence on RAW264.7 macrophages, this experiment was aimed to provide theoretical basis for the development and utilization of A.americana Medikus polysaccharide.The detection results are as follows:(1) The yield of crude polysaccharide is 3.7%. After further purification, the yield of MP1 is 6.11%,MP1-1 has the highest sugar content (95.3%) and the lowest protein content (0.8%)of the five elution fractions;(2) From HPLC and GPC test results, we can see A.americana Medikus polysaccharide components are heteropolysaccharides, mainly of dextran. MP1-1 and MP2 contain glucose, mannose, Arabia sugar, rat Li and galactose acid, MP1 does not conclude rat Li sugar, galactose is not in MP3, the amount of glucose is the lowest and mannose, Arabia sugar and galactose acid are the highest in MP2 among the five components. The relative molecular mass of MP1 and MP2 are low, MP3 and MP4 are higher, and the composition of MP1-1 is more uniform;(3) From FT-IR and NMR test results, in the range of 4000-400cm-1, A.americana Medikus polysaccharide components all have the characteristic absorption peaks. It is indicate that the five components are mainly pyranose sugar ring configuration. MP1, MP2 and MP1-1 are including a-glycosidic bond, MP3 and MP4 are including ?- glycosidic bond. They all have the characteristic absorption peak of the rat Li,MP2 contains the methyl group of acetyl group,A.americana Medikus polysaccharides have complex structures, it is mainly based on dextran as the main chain, Arabia sugar or mannose as the side chain.(4) The effects of A. americana Medikus polysaccharide fractions on RAW264.7 macrophages are as follows: MP1 and MP1-1 play a certain role in promoting the increment of macrophages, the phagocytosis of neutral red and the secretion of NO, dose and time dependent in a certain concentration range. MP2, MP3, MP4 had no significant effect on the increment of RAW264.7 macrophages, but had a significant promoting effect on the secretion of NO by macrophages. In addition, MP2 has effect in promoting macrophage phagocytosis of neutral red,it is may be related to a small amount of acetyl group in MP2.