Figure 5.

Glucosinolate hydrolysis products are metabolized via the mercapturic acid pathway and intramolecular cyclizations by H. armigera larvae. (A–C) Volcano plots of extracted LC-MS/MS features from non-targeted UHPLC-HRMS analyses indicate that the major metabolites of 3msop-ITC (A), 3but-ITC (B), and goitrin (C) are all formed by conjugation to glutathione (GSH), further hydrolysis of the amino acid constituents of GSH to give CysGly and Cys conjugates, and intramolecular cyclizations to give cyclic conjugates. The proposed goitrin metabolite (D) corresponds to the MS feature at 2.2 min in (C), while a signal corresponding to the proposed metabolite (E) was detectable in manually extracted ion chromatograms from faeces extracts but was too small to be extracted automatically by the software. The proposed formation of these cyclic metabolites is shown in (F).