Mass Spectrometric Characterization of Benzoxazinoid Glycosides from Rhizopus-Elicited Wheat (Triticum aestivum) Seedlings

• DOI: 10.1021/acs.jafc.6b02889
• Publication Date: 2016-07-19T07:13:02Z
• Authors: Wouter J. C. de B...; Jean-Paul Vincken; Katharina Duran; Harry Gruppen
• Keywords: elicitation; phytoalexin; 0301 basic medicine; 2. Zero hunger; Molecular Structure; cereal grain; Germination; LC-MS; Benzoxazines; 03 medical and health sciences; benzoxazinoid classification; germination; plant defense; Seedlings; Seeds; Glycosides; Rhizopus oryzae; Rhizopus; Triticum

Benzoxazinoids function as defense compounds and have been suggested to possess health-promoting effects. In this work, the mass spectrometric behavior of benzoxazinoids from the classes benzoxazin-3-ones (with subclasses lactams, hydroxamic acids, and methyl derivatives) and benzoxazolinones was studied. Wheat seeds were germinated with simultaneous elicitation by Rhizopus. The seedling extract was screened for the presence of benzoxazinoid (glycosides) using reversed-phase ultra-high-performance liquid chromatography with photodiode array detection coupled in line to multiple-stage mass spectrometry (RP-UHPLC-PDA-MS(n)). Benzoxazin-3-ones from the different subclasses showed distinctly different ionization and fragmentation behaviors. These features were incorporated into a newly proposed decision guideline to aid the classification of benzoxazinoids. Glycosides of the methyl derivative 2-hydroxy-4-methoxy-1,4-benzoxazin-3-one were tentatively identified for the first time in wheat. We conclude that wheat seedlings germinated with simultaneous fungal elicitation contain a diverse array of benzoxazinoids, mainly constituted by benzoxazin-3-one glycosides.