In plants belonging to the order of Caryophyllales, pectic neutral side chains can be substituted with ferulic acid. The ability of ferulic acid to form intra-and/or intermolecular polysaccharide cross-links by dimerization was shown by the isolation and characterization of diferulic acid oligosaccharides from monocotyledonous plants. In this study, two diferulic acid oligosaccharides were isolated from the enzymatic hydrolyzate of seeds of the dicotyledonous pseudocereal quinoa by gel permeation chromatography and preparative HPLC and unambiguously identified by LC-MS2 and 1D/2D NMR spectroscopy. The isolated oligosaccharides are comprised of 5-5-and 8-O-4-diferulic acid linked to the O2-position of the nonreducing residue of two (1→5)-linked arabinobioses. To get insight into the structure and the degree of phenolic acid substitution of the diferuloylated polysaccharides, polymeric sugar composition, glycosidic linkages, and polysaccharide-bound monomeric phenolic acids and diferulic acids were analyzed. This study demonstrates that diferulic acids are involved into intramolecular and/or intermolecular cross-linking of arabinan chains and may have a major impact on cell wall architecture of quinoa and other dicotyledonous plants of the order of Caryophyllales.
Bibliographical noteFunding Information:
Funding for NMR instrumentation was provided by the Office of the Vice President for Research , the Medical School , the College of Biological Science , NIH , NSF , and the Minnesota Medical Foundation .
© 2015 Elsevier Ltd. All rights reserved.
- Cell wall
- Chenopodium quinoa
- Dietary fiber
- Diferulic acids