Characterization of acetylated 4-O-methylglucuronoxylan isolated from aspen employing 1H and 13C NMR spectroscopy

Carbohydr Res. 2000 Dec 1;329(4):807-15. doi: 10.1016/s0008-6215(00)00249-4.


Water-soluble hemicelluloses were extracted from milled aspen wood (Populus tremula) employing microwave oven treatment at 180 degrees C for 10 min. The final pH of this extract was 3.5. From this extract oligo- and polysaccharides were isolated and subsequently fractionated by size-exclusion chromatography. The structures of the saccharides in three of the fractions obtained were determined by 1H and 13C NMR spectroscopy, using homonuclear and heteronuclear two-dimensional techniques. The polysaccharides present in the two fractions eluted first were O-acetyl-(4-O-methylglucurono)xylans. The average degree of acetylation of the xylose residues in these compounds was 0.6. The structural element -->4)[4-O-Me-alpha-D-GlcpA-(1-->2)][3-O-Ac]-beta-D-Xylp-(1 --> could also be identified. On the average, these two xylans were composed of the following (1-->4)-linked beta-D-xylopyranosyl structural elements: unsubstituted (50 mol%), 2-O-acetylated (13 mol%), 3-O-acetylated (21 mol%), 2,3-di-O-acetylated (6 mol%) and [MeGlcA alpha-(1-->2)][3-O-acetylated] (10 mol%). Most of the 4-O-methylglucuronyl and acetyl substituents in the isolated polysaccharides survived the microwave oven treatment. The third fraction, eluted last, contained acetylated xylo-oligosaccharides, with minor contamination by an acetylated mannan. In the case of these xylo-oligosaccharides, the average degree of acetylation was 0.3.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation
  • Carbohydrate Conformation
  • Carbohydrate Sequence
  • Cell Wall / chemistry
  • Chromatography
  • Magnetic Resonance Spectroscopy
  • Microwaves
  • Molecular Sequence Data
  • Polysaccharides / chemistry*
  • Polysaccharides / isolation & purification*
  • Rosales / chemistry
  • Wood*
  • Xylans / chemistry*
  • Xylans / isolation & purification*


  • Polysaccharides
  • Xylans
  • hemicellulose