Isolation and purification and structural characterization of acidic polysaccharide FCP5-A from fruit of Cornus officinalis

Fruit of Cornus officinalis has been used in Chinese traditional medicine for over two thousand of years. Polysaccharides, as important components of Cornus officinalis, have attracted much attention. An acidic polysaccharide FCP5-A was isolated from fruit of Cornus officinalis with water extraction and column chromatography. HPGPC shows that it was homogeneous polysaccharide with an average molecular weigh of 8.7 x 10(4). Monosaccharide analysis by GC shows that it was composed of rhamnose, arabinose, galactose and galacturonic acid with a molar ratio of 1: 5.7: 0.6: 1.2. By means of IR, GC, partial hydrolysis with acid, uronic acid reduction, methylation, GC-MS and C-13 NMR analysis, the results indicate that FCP5-A was a branched polysaccharide rich in arabinose. The backbone was composed of 12-linked Rha and 1,4-linked GalA, with side chains attached to 0-4 of the rhamnosyl residues. The side chains contained highly branched arabinan and short linear 1,3-linked galactan. It was concluded that FCP5-A was a new acidic branched polysaccharide of Cornus officinalis.