The Study On Absorption Mechanism Of Astragalus Polysaccharide

Astragalus polysaccharide (APS) is the main component of Astragalus mongholicus, a well-known naturceutical in Chinese traditional medicine. Astragalus polysaccharide seem to be able to stimulate white blood cell production and spurs the activity of killer T cells, thus strengthen the immune system.The preparation now available on the market includes injection,oral solution and granules. However, the mechanism of intestinal absorption for Astragalus polysaccharide is not yet clear.Rat evered gut sac system of different intestinal section (jejunum, ileum, and duodenum) was used for the study on absorption characteristics and the absorption mechanism of APS. The solution inside the sac was collected and the APS concentration was determined by anthrone-sulfuric acid colorimetry. The data showed that APS absorption rate was the same for all sections of the intestine (p>0.05), but varied in buffer solution with different pH values. Best absorption rate was observed when buffer solution had a pH value is 6.8.The absorption rate did not show a linear relationship with the increment of dose or concentration, suggesting a phenomenon of saturation for the absorption. Therefore a transpoter may be needed for APS absorption. The effect of different absorption enhancers was also investigated. The results indicated that sodium taurocholate hydrate, SDS and Tween 80 all improved absorption of APS.The linearity, the revovery and the accuracy of the method were all good for the anthrone-sulfuric acid method and DNS method. In addition, typeIII ZTC1+1 natural clerifying agent was found better in performance than Sevege method for deproteinization procedure, and D280 anion large pore absorbing rasin was better than H2O2 method for decolorization procedure. The purity of APS reached 69.9% in this study.