STRUCTURE OF A FERULOYLATED ARABINOXYLAN TETRASACCHARIDE THAT CONTAINS THE BETA-D-XYLP-(1 -] 2)-ALPHA-L-ARAF ELEMENT BY H-1 AND C-13 NMR-SPECTROSCOPY

The determination of the structure of {[5-O-(E)-feruloyl] [O-beta-D-xylopyranosyl-(1 --> 2)]-O-alpha-L arabinofuranosyl-(1 --> 3)}-O-beta-D-xylopyranosyl-(1 --> 4)-D-xylopyranose, a compound isolated from the cell walls of Gramineae, is presented. Use is made of 1D HOHAHA and 2D H-1, C-13 H-1-detected HMQC to assign the H-1 and C-13 NMR spectra of the individual residues. The 2D H-1, C-13 H-1-detected HMBC and H-1, H-1 ROESY, in comparison with H-1, H-1 COSY, experiments are used to establish the inter-residue linkages. This is the first report of a feruloylated arabinoxylan that contains the beta-D-Xylp-(1 --> 2)-alpha-L-Araf element.