Untargeted Metabolomic Analysis of Nonvolatile and Volatile Glucosinolates in Brassicaceae

Glucosinolates (GLSs) are a group of plant secondary metabolites mainly found in Cruciferous plants. The main hydrolysis products of GLSs, isothiocyanates (ITCs), are the bioactive metabolites that have shown plant defense and human cancer prevention properties. Untargeted metabolomic analysis of plant metabolites can uncover the profiles of these bioactive phytochemicals in specific plants and discover potential human health promoting products. We have developed an integrated metabolomic analysis method for plant samples, with specific focus on nonvolatile GLSs and volatile ITCs. In this chapter, we describe in detail the protocols, including metabolite extraction, high resolution LC-MS and GC-MS analysis, and data processing. The method is readily applicable to untargeted analysis of other nonvolatile and volatile metabolites in plants.