Characterization of Polysaccharides Having Activity on the Reticuloendothelial System from the Rhizome of Curcuma longa

Abstract

Three polysaccharides, named ukonan A, ukonan B and ukonan C, were isolated from the rhizomes of Curcuma longa L. They were homogeneous on electrophoresis and gel chromatography, and showed remarkable reticuloendothelial system-potentiating activity in a carbon clearnce test. They are composed of L-arabinose : D-xylose : D-galactose : D-glucose : L-rhamnose : D-galacturonic acid in the molar ratios of 12 : 4 : 12 : 1 : 4 : 10 (ukonan A), 12 : 4 : 12 : 1 : 2 : 4 (ukonan B) and 8 : 3 : 6 : 14 : 2 : 3 (ukonan C), in addition to small amounts of peptide moiety. Methylation analysis, carbon-13 unclear magnetic resonance and periodate oxidation studies indicated the structural features of ukonan B, the major one in terms of the activity. It has acidic arabino-galactan type structural units.