Structural investigation of a heteropolysaccharide isolated from the green fruits of Capsicum annuum

A water-soluble polysaccharide isolated from the hot water extract of the green fruits of Capsicum annuum was found to consist of 3-O-acyl-l-rhamnose, d-methyl galacturonate, 6-O-methyl-d-galactose in a molar proportion of nearly 1:2:1. Structural investigation of the polysaccharide was carried out using total hydrolysis, methylation analysis, periodate oxidation followed by GLC–MS, and NMR experiments. On the basis of the above-mentioned experiments it is concluded that the following repeating unit is present in the polysaccharide.