Abstract

MAGATON, Andréia da Silva; PILO-VELOSO, Dorila  and  COLODETTE, Jorge Luiz. Characterization of O-acetil-(4-O-methylglucurono)xylans from Eucalyptus urograndis. Quím. Nova [online]. 2008, vol.31, n.5, pp. 1085-1088. ISSN 0100-4042.  http://dx.doi.org/10.1590/S0100-40422008000500027.

The O-acetyl-4-O-methyl-(glucurono)xylans were isolated from E. urograndis by extraction with dimethyl sulfoxide, analysed for monosaccharide composition and structurally characterized by NMR spectroscopy. These xylans contained one 4-O-methyl-glucuronic acid substituent and 5.5 acetyl groups for approximately 10 xylose residues. About 10% of 4-O-methyl-glucuronic acid (MeGlcA) units were branched at O-2. The O-acetyl-4-O-methyl-(glucurono)-xylans were composed of the following (1 → 4)-linked β-D-xylopyranosyl structural elements: unsubstituted (51 mol%), 2-O-acetylated (12 mol%), 3-O-acetylated (20 mol%), 2,3-di-O-acetylated (6 mol%) and [MeGlcA α-(1 → 2)] [3-O-acetylated] (11 mol%). The weight-average molar mass and polydispersity of this xylan were 34.9 kDa and 1.16, respectively, as measured by size-exclusion chromatography.

Keywords : Eucalyptus urograndis; xylans; NMR.