Structural studies of an arabinoxylan isolated from Litsea glutinosa (Lauraceae)

A water-soluble arabinoxylan ( d-xylose and l-arabinose in the molar ratio 1.0:3.4) was isolated from the mucilaginous bark of Litsea glutinosa (Lauraceae). The results of methylation analysis, partial hydrolysis, and 1H- and 13C-n.m.r. spectroscopy indicated a backbone of (1→4)-linked β- d-xylopranosyl residues substituted at both positions 2 and 3 with side chains composed of either single or (1→3)-linked arabinofuranosyl residues. Both α- l- and β- l-arabinofuranosyl residues were present. It is possible that side chains composed of two β- l-arabinofuranosyl residues are attached mainly at O-2 of some xylosyl residues.