Combining NMR and MS to Describe Pyrrole-2-Carbaldehydes in Wheat Bran of Radiation

Nuclear magnetic resonance (NMR)
spectroscopy and mass
spectrometry
(MS) are indispensable analytical tools to provide chemical fingerprints
in metabolomics studies. The present study evaluated radiation breeding
wheat lines for chemical changes by non-targeted NMR-based metabolomics
analysis of bran extracts. Multivariate analysis following spectral
binning suggested pyrrole-2-carbaldehydes as chemical markers of four
mutant lines with distinct NMR fingerprints in a δH range of 9.28–9.40 ppm. Further NMR and MS data analysis,
along with chromatographic fractionation and synthetic preparation,
aimed at structure identification of marker metabolites and identified
five pyrrole-2-carbaldehydes. Quantum-mechanical driven 1H iterative full spin analysis (QM-HiFSA) on synthetic pyrrole-2-carbaldehydes
provided a precise description of complex peak patterns. Biological
evaluation of pyrrole-2-carbaldehydes was performed with nine synthetic
products, and six compounds showed hepatoprotective effects via modulation
of reactive oxygen species production. Given that three out of five
identified in wheat bran of radiation were described for hepatoprotective
activity, the value of radiation mutation to greatly enhance pyrrole-2-carbaldehyde
production was supported.