A reticuloendothelial system-activating glycan from the roots of Astragalus membranaceus

From the hot water extract of the roots of Astragalus membranaceus, a glycan, designated as AMem-P, has been isolated by treatment with cetyltrimethylammonium bromide followed by column chromatography on Toyopearl HW60F and Con A-Sepharose columns. Chemical and spectroscopic studies established that the glycan possesses mainly α-1,2-linked l-rhamno-α-1,4-linked d-galacturonan structure. Terminal and α-1,5-linked l-arabinofuranose, terminal, β-1,3-, β-1,4- and β-1,6-linked and 3,6-branched d-galactose, and 2,4-branched l-rhamnose residues were also identified as the component sugar units. The glycan showed remarkable reticuloendothelial system-potentiating activity in the carbon clearance test.