Thiol Reactome Profiling in Plant-Derived Foods and Discovery of an Abundant Insecticidal Natural Product (<i>R</i>)-Dihydromaleimide in Snow Pea (<i>Pisum sativum</i>)

While thiol-reactive compounds have been extensively utilized by plants as defensive metabolites, prior investigations into these natural products remained limited. We employed a reactivity-directed analysis method utilizing high-resolution mass spectrometry to conduct thiol reactome profiling on extracts from 70 different plant-derived foods, resulting in the tentative prediction of chemical formulas of 71 abundant molecular adduct ions. Then, we selected a prominent adduct ion for structural elucidation, leading to the identification of (<i>R</i>)-dihydromaleimide (DHM) and (<i>R</i>)-dihydromaleimide β-d-glucoside (DHMG) in snow pea (<i>Pisum sativum</i>). DHM demonstrated insecticidal properties against the fall armyworm (FAW) and <i>Protaetia brevitarsis</i> and antifeedant activity against FAW, with oxidative stress as a contributing mechanism. Quantitative analyses indicated considerable concentrations of DHMG and DHM in many parts of pea plants and easy conversion of DHMG to DHM in aqueous extracts. This research provided a feasible strategy for the high-throughput screening and discovery of novel botanical natural products for pest control.