Structural characterization of an acidic polysaccharide from Dalbergia sissoo Roxb. leaves

The composition and structure of an acidic polysaccharide from the leaves of Dalbergia sissoo was studied using hydrolytic, methylation, (1)H/(13)C heteronuclear multiple quantum coherence (HMQC) and periodate oxidation experiments. The repeating unit of sissoo polysaccharide was found to be composed of α-L-rhamnose, β-D-glucuronic acid, β-D-galactose and β-D-glucose in the molar ratio of 1.00:1.00:2.00:2.33, respectively. The structure of polysaccharide was mainly composed of (1→2), (1→3), (1→4) linkages. Based on extensive laboratory experiments, the structure having the repeating units of the acidic polysaccharide from sissoo leaves, with unusual branching, was established.