A polysaccharide with 40% mono-O-methylated monosaccharides from the bark of Cola cordifolia (Sterculiaceae), a medicinal tree from Mali (West Africa)

A novel type polysaccharide was isolated from the bark of Cola cordifolia (Cav.) R. Br. (Sterculiaceae), a plant used in traditional medicine in Mali (West Africa). The polysaccharide was isolated from the water extract by ion exchange chromatography. Structural studies showed that this was a highly complex new type polysaccharide containing 20% of 2,3- and 2,4-linked rhamnose, 24% of galacturonic acid mostly 4-linked, 15% of terminal, 3- and 4-linked galactose, 20% of terminal and 3-linked 2-O-methyl galactose, 18% of 4-O-methyl glucuronic acid which was also terminally linked, and 2% of terminal 2-O-methyl fucose. This paper reports in addition to structural features, physical property and complement fixating activity using human serum as target of this novel polysaccharide. This is a first report of a plant polysaccharide containing such a diverse composition and quantity of natively methylated monosaccharides.