Structural studies on a polysaccharide of mahua ( Madhuca indica) flowers

Abstract

On hydrolysis, the purified polysaccharide, PS-AII, of Mahua flowers yielded d-galactose, d-glucose, l-arabinose, and d-glucuronic acid in the mole ratios of 3.9:2.3:1.3:1.0. A degraded polysaccharide was prepared by autohydrolysis of an aqueous solution of PS-AII. Methylation studies were conducted on the degraded polysaccharide, the whole polysaccharide, and their carboxyl-reduced derivatives. The results were corroborated by those from periodate oxidation followed by Smith degradation. The anomeric configurations of the different sugar residues in the whole polysaccharide and carboxyl-reduced, degraded polysaccharide were determined by chromium trioxide oxidation. Finally, the oligosaccharides obtained by autohydrolysis of the whole polysaccharide and by graded hydrolysis of the degraded polysaccharide were characterized. From these results, a tentative structure was assigned to the average repeating-unit in polysaccharide PS-AII.