2D-HSQC-NMR-Based Screening of Feruloylated Side-Chains of Cereal Grain Arabinoxylans

Rachel R. Schendel, Mirko Bunzel

Research output: Contribution to journalArticlepeer-review

Abstract

Arabinoxylans of commelinid monocots are characterized by high contents of ferulic acid that is incorporated into arabinose-bearing side-chains of varying complexity. Species-related differences in the feruloylated side-chain profiles of grain arabinoxylans are observed and lead to differences in arabinoxylan functionality. Here, a semi-quantitative assay based on 1H-13C-correlation NMR spectroscopy (HSQC experiment) was developed to profile feruloylated side-chains of cereal grain arabinoxylans. Following acidic liberation of the feruloylated side-chains from the xylan backbone and a clean-up step using C18 solid phase extraction, the feruloylated oligosaccharides FA (5-O-trans-feruloyl-L-arabinofuranose), FAX (β-d-xylopyranosyl-(1 → 2)-5-O-trans-feruloyl-l-arabinofuranose) and FAXG (α-l-galactopyranosyl-(1 → 2)-β-d-xylopyranosyl-(1 → 2)-5-O-trans-feruloyl-l-arabinofuranose) were analyzed by HSQC-NMR. Marker signals were identified for each compound, and experimental conditions such as solvent and internal standard as well as measurement and processing conditions were optimized for a semi-quantitative determination. The approach was validated with respect to accuracy, precision, limit of detection, and limit of quantification. The newly developed approach was applied to several cereal samples including oats, popcorn maize, wheat, and wild rice. Data were compared to an HPLC-DAD/MS approach published earlier by our group, demonstrating that the results of the HSQC approach were comparable to the more time-consuming and technically more challenging HPLC-DAD/MS method.

Original languageEnglish
Article number951705
JournalFrontiers in Plant Science
Volume13
DOIs
StatePublished - Jul 7 2022

Bibliographical note

Funding Information:
We acknowledge support by the KIT-Publication Fund of the Karlsruhe Institute of Technology.

Publisher Copyright:
Copyright © 2022 Schendel and Bunzel.

Keywords

  • 2D-NMR
  • arabinoxylan
  • ferulic acid
  • feruloylated side-chains
  • HSQC

ASJC Scopus subject areas

  • Plant Science

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