Isolation, H-1 and C-13 NMR studies of (4-O-methyl-D-glucurono)-D-xylans from luffa fruit fibres, jute bast fibres and mucilage of quince tree seeds

摘要

The (4-O-methyl-D-glucurono)-D-xylans isolated from luffa fruit fibres (Luffa cylindrica), jute bast fibres (Corchorus capsularis) and mucilage of the seeds of the quince tree (Cydonia oblonga) were studied by H-1 and C-13 NMR spectroscopy. Their NMR spectra were grossly similar, but the molar proportions of D-Xyl and 4-O-Me-D-GlcA varied and were found to be, respectively, 7.5:1, 5:1 and 2:1 for luffa fibres, jute bast fibres and quince tree seeds mucilage. The mucilage extracted from the seeds of the quince tree contained cellulose microfibrils strongly associated with a glucuronoxylan possessing a very high proportion of glucuronic acid residues. In addition to 4-O-methyl-alpha-D-glucopyranosyluronic residues the presence of alpha-D-glucopyranosyluronic residues was noticed, respectively, in the molar ratio 4-O-Me-D-GlcA and-D-GlcA 9:1. (C) 1998 Elsevier Science Ltd. All rights reserved. [References: 23]