[Structural characterization of a glucan isolated from Gastrodia elata].

To study a glucan (GB II) isolated from Gastrodia elata.The glucan was obtained with water extraction, alcohol precipitate, DEAE-Sepharose Fast Flow column and Sepharose CL-6B column chromatography; sugar composition analysis, IR and NMR were used to determine the structural feature.The molecular weight of the glucan was 4 300 dalton estimated by HPGPC; it contained 27 glucose residues, which mainly composed of alpha-D-(1-->4)-glucose with little glucuronic acid and branch O-6 points.The glucan was a new glucan for the first report from Gastrodia elata.