Anogeissus leiocarpus gum. Part II. Fractionation of the gum and partial hydrolysis of leiocarpan A

Abstract

Fractionation of Anogeissus leiocarpus gum affords two distinct polysaccharides, leiocarpan A and leiocarpan B. Partial hydrolysis of leiocarpan A furnishes a complex mixture of neutral and acidic oligosaccharides including 3-O-β-L-arabinofuranosyl-L-arabinose (I), 3-O-β-L-arabinopyranosyl-L-arabinose (II), 3-O-β-D-galactopyranosyl-D-galactose (III), 6-O-β-D-galactopyranosyl-D-galactose (IV), 3-O-β-D-galactopyranosyl-L-arabinose (V), O-β-D-galactopyranosyl-(1→6)-O-β-D-galactopyranosyl-(1→3)-L-arabinose (VI), 6-O-(β-D-glucopyranosyluronic acid)-D-galactose (VII), O-(β-D-glucopyranosyluronic acid)-(1→6)-O-D-galactopyranosyl-(1→3)-L-arabinose (VIII), 2-O-(β-D-glucopyranosyluronic acid)-D-mannose (IX), and O-(D-glucopyranosyluronic acid)-(1→2)-O-D-mannopyranosyl-(1→4)-O-(D-glucopyranosyluronic acid)-(1→2)-D-mannose (X). Re-examination of the partial hydrolysis products from gum ghatti (from Anogeissus latifolia) has shown that the acidic tetrasaccharide (X) is also formed from this polysaccharide.