Structure of a new acid-polysaccharide from the bark of Pterospermum acerifolium

Abstract

A new acid-polysaccharide isolated from the bark of Pterospermum acerifolium N.O. Sterculiaceae has been shown to be composed of residues of D-galacturonic acid, D-galactose, and L-rhamnose in the molar ratio 5 : 3 : 3, repectively. Partial acid hydrolysis gave three oligosaccharides, 2-O-(α-D-galactopyranosyl uronic acid)-L-rhamnose, 4-O-(α-D-galactopyranosyl uronic acid)-D-galacturonic acid, and O-D-galactopyranosyl uronic acid(1 → 2)-O-L-rhamnopyranosyl-(1 → 4)-D-galactose. The various glycosidic linkages have been determined by the products from hydrolysis of the methylated polysaccharide and confirmed by periodate oxidation of the polysaccharide.