SEPARATION, ISOLATION AND CHARACTERIZATION OF ACIDIC POLYSACCHARIDES FROM THE INNER BARK OF ULMUS-GLABRA HUDS

Pectin type polysaccharides were extracted from the inner bark of Ulmus glabra Huds., using water at 50-degrees-C. After redissolving the product by boiling, fractionation into 9 polymers was achieved by a combination of two different ion exchange columns. The three most abundant polymers were isolated and characterized. The polysaccharides appeared to have structural differences. The two fractions A(FPLC) and B(FPLC) contain galacturonic acid, galactose and rhamnose, while C(FPLC) in addition contains 3-O-methylgalactose, glucuronic acid and acetyl groups. The backbone of all three polysaccharides consists of 4-linked alpha-D-galactopyranosyl-uronic acid interspersed with 2-linked alpha-L-rhamnopyranosyl residues. The side chains on A(FPLC) and B(FPLC) consist of galactose units attached to C-3 of the rhamnose, while the side chains of C(FPLC) are mainly linked through C-4 of rhamnose. These include 4-linked 3-O-methylgalactose. After weak acid hydrolysis, 5 acidic oligosaccharides were isolated and characterized.