Structural characterization of a 2-O-acetylglucomannan from Dendrobium officinale stem.
A heteropolysaccharide obtained from an aqueous extract of dried stem of Dendrobium officinale Kimura and Migo by anion-exchange chromatography and gel-permeation chromatography, was investigated by chemical techniques and NMR spectroscopy, and is demonstrated to be a 2-O-acetylglucomannan, composed of mannose, glucose, and arabinose in 40.2:8.4:1 molar ratios. It has a backbone of (1-->4)-linked beta-d-mannopyranosyl residues and beta-d-glucopyranosyl residues, with branches at O-6 consisting of terminal and (1-->3)-linked Manp, (1-->3)-linked Glcp, and a small proportion of arabinofuranosyl residues at the terminal position. The acetyl groups are substituted at O-2 of (1-->4)-linked Manp and Glcp. The main repeating unit of the polysaccharides is reported.
Hua
Yun-Fen
YF
Lab of Plant Systematic Evolution and Biodiversity, College of Life Sciences, Zhejiang University, Hangzhou 310029, China.
Zhang
Ming
M
Fu
Cheng-Xin
CX
Chen
Zhang-Hui
ZH
Chan
Gilbert Yuk Sing
GY
D002240:Carbohydrate Sequence; D031667:Dendrobium / Q000737:chemistry*; D004187:Disaccharides / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008351:Mannans / Q000737:chemistry* / Q000302:isolation & purification; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry / Q000302:isolation & purification; D018547:Plant Stems / Q000737:chemistry*
D004187:Disaccharides; D008351:Mannans; D009844:Oligosaccharides; C022901:(1-6)-alpha-glucomannan