[Isolation, purification and structural analysis of a polysaccharide MDG-1 from Ophiopogon japonicus].

To separate and purify the anti-myocardial ischemic polysaccharide fraction with a homogenous molecular weight from Ophiopogon japonicus, then study the chemical structure of the parts.Crude polysaccharides were prepared by extracting the tube root fraction of Ophiopogon japonicus with water, then precipitation with ethanol. From the crude polysaccharides, the polysaccharide of MDG-1 was separated and purified using ultrafiltration, DEAE Sepharose FF and Sephadex G-25 column chromatography. Its structure was studied by complete hydrolysis, periodate oxidation, Smith degradation, methylation analysis, 1H NMR and 13C NMR analysis etc.MDG-1 was a water-soluble beta-D-fructosan, containing a backbone composed of Fruf (2 --> 1), and a branch of Fruf (2 --> 6) Fruf (2 --> per average 2. 8 of main chain residues. Mn, Mw and Mp of MDG-1 were 3 400, 4 800 and 5 000, respectively. MDG-1 contains trace of Glc, which maybe connect to its reducing terminal. Molar ratio of Fru and Glc is approximately 35: 1.