Stepwise mass spectrometry-based approach for confirming the presence of benzoxazinoids in herbs and vegetables

Introduction: Benzoxazinoids (BXs) are plant phytochemicals that have both defensive properties in plants and therapeutic effects in humans. The presence of BXs has been largely studied in the Poaceae family (monocots). To study the presence or absence of BXs in dicotyledons and monocotyledons outside the Poaceae family, parts of 24 plant species at several growth stages were selected for analysis, some of which were already known to contain BXs.

Objectives: To devise a stepwise mass spectrometry-based approach for confirming the presence of BXs in plant samples, and to use the method to explore the status of BXs in selected plant species.

Experimental: Plant samples were extracted using accelerated solvent extraction and analysed using triple-quadrupole liquid chromatography-mass spectrometry.

Results: The use of different columns, double mass transitions, and ion ratios proved to be a robust tool for confirming the presence of BXs in different plant species. By this method, the presence of BXs was confirmed in three of the 24 species. Double-hexose forms of BXs, which have not been reported before in dicotyledons, were confirmed to be present in the dicotyledon plants Acanthus mollis and Lamium galeobdolon, and the presence of BXs in the seeds of Consolida orientalis is reported for the first time here. High concentrations of BXs were found in the aerial parts of Acanthus mollis and Lamium galeobdolon, at 20 and 32 μmol/g plant dry weight, respectively.

Conclusions: The stepwise approach described in this work confirmed the presence of BXs in new samples.

Keywords: Acanthus mollis; Consolida orientalis; DIBOA-glc-hex; HBOA-glc-hex; LC-MS/MS; Lamium galeobdolon; benzoxazinoids.