Current Methods for the Extraction and Analysis of Isothiocyanates and Indoles in Cruciferous Vegetables

Abstract

Cruciferous vegetables are characterized by the presence of sulfur-containing secondary plant metabolites known as glucosinolates (GLS). The consumption of cruciferous vegetables such as broccoli, cabbage, rocket salad, and cauliflower has been related to the prevention of non-communicable diseases. Their beneficial effects are attributed to the enzymatic degradation products of GLS, e.g., isothiocyanates and indoles. Owing to these properties, there has been a shift in the last few years towards the research of these compounds and a wide range of methods for their extraction and analytical determination have been developed. The aim of this review is to present the sample preparation and extraction procedures of isothiocyanates and indoles from cruciferous vegetables and the analytical methods for their determination. The majority of the references that have been reviewed are from the last decade. Although efforts towards the application of eco-friendly non-conventional extraction methods have been made, the use of conventional solvent extraction is mainly applied. The major analytical techniques employed for the qualitative and quantitative analysis of isothiocyanates and indoles are high-performance liquid chromatography and gas chromatography coupled with or without mass spectrometry detection. Nevertheless, the analytical determination of isothiocyanates presents several problems due to their instability and the absence of chromophores, making the simultaneous determination of isothiocyanates and indoles a challenging task.

Bacterial-Assisted Extraction of Bioactive Compounds from Cauliflower

“…Moreover, the solubilisation, and thus, the extraction efficiency, of some compounds occurs in polar organic solvents, which were not used in this work. For example, isothiocyanates, relevant anticancer compounds abundantly present in Brassicaceae [ 27 ], are usually extracted from fresh material using organic solvents, and even in those cases, with extremely variable returns, as reported in the literature [ 28 , 29 , 30 ]. In general, however, organic solvents guarantee much higher yields with respect to those reported in this work ( Table 1 ).…”

Advances in Discoveries of Plant Phytochemicals

“…The entire conversion is catalyzed by endogenous myrosinase (thioglucoside glucohydrolase) enzyme released after chopping and chewing of raw vegetables or physical damage such as insect attack (Oliviero et al, 2018). Myrosinase reacts (Devkota, 2020) and HPLC-DAD and UHPLC-HRMS/MS for ITCs (Karanikolopoulou et al, 2021). If myrosinase is denatured during ingestion, GLCs metabolism can also be triggered by gut microbiota (Luang-In et al, 2014).…”

Determination of Phenethyl Isothiocyanate, Erucin, Iberverin, and Erucin Nitrile Concentrations in Healthy and Pieris rapae-Infected Broccoli Tissues Using Gas Chromatography-Mass Spectrometry

“…3.2. Extraction of Isothiocyanates PEITC, ER, 3MIC, and Nitrile 5MITN from Broccoli Samples, and Determination via GC-MS Among the various solvents (methanol, methyl tert-butyl ether, dichloromethane, chloroform, and ethanol) that have been used for the extraction of ITCs and nitriles from the Brassicaceae family plants [37], dichloromethane was chosen and used, since it is a common, nonpolar solvent.…”