STRUCTURAL FEATURES OF WATER-SOLUBLE NOVEL POLYSACCHARIDE COMPONENTS FROM THE LEAVES OF TRIDAX-PROCUMBENS LINN

Two water-soluble polysaccharide fractions, WSTP-IA and WSTP-IB were p urified from the leaves of Tridax procumbens Linn. with graded ethanol precipitation followed by mild delignification and size-exclusion chr omatography. WSTP-IA contained L-Ara f and D-Gal p in similar to 1:3 m olar proportions, and WSTP-IB contained only D-Gal p as the major suga r component. The results of methylation linkage analysis, and H-1 and C-13 NMR studies on the native and modified polysaccharides, indicated that WSTP-IA is an L-arabino-D-galactan with a beta-(1 --> 6)-D-galac tan main chain in which at least one in every two D-Gal p residues car ries single residues of either L-Ara f (alpha-/beta-) or beta-D-Gal p end-group as substituents at O-3. WSTP-IB is a linear beta-(1 --> 6)-D -galactan. This is the first report of polysaccharides containing a be ta-(1 -->) 6)-D-galactan main chain isolated from plant sources.