Isolation and structural elucidation of a low-molecular-weight polysaccharide from the roots of Panax ginseng C. A. Meyer

A low-molecular-weight polysaccharide named MCGP-L was extracted and purified from the roots of Mountain cultivated ginseng (Panax ginseng C. A. Meyer). The polysaccharide MCGP-L was purified by molecular exclusion chromatography using the Sephadex G-25 column. The average molecular weight of MCGP-L was estimated to be 3 × 10³ kDa. Monosaccharide composition analysis showed MCGP-L was composed of three kinds of monosaccharide: D-glucose, D-galactose and D-mannose. The physicochemical properties and structural characteristics of MCGP-L were investigated by the combination of chemical and instrumental analysis such as methylation analysis, High Performance Gel-Permeation Chromatography (HPGPC), High Performance Liquid Chromatography (HPLC) and Nuclear Magnetic Resonance (NMR). The backbone of MCGP-L was composed of (1→4)-linked-α-D-Glcp residues and with branch chain substituted at O-6 position of (1→4,6)-linked-α-D-Glcp. The branch chain consists of →6)-α-D-Galp-(1→, →2)-α-D-Manp-(1→ and β-D-Glcp-(1→.