The nutritional value of Brassicaceae and order Brassicales superfamilies is primarily based on the presence of bioactive secondary metabolites known as isothiocyanates yielded through their bioconversion from glucosinolates. The aim of this study was to identify and quantify the content of glucosinolates, isothiocyanates and their myrosinase-induced bioconversion rates across selected edible vegetables of these superfamilies. The extraction of glucosinolates was performed into aqueous methanol whereas their conversion to isothiocyanates was performed in PBS followed by extraction with various solvents. Isothiocyanates were derivatized and quantified via UPLC-QqQ-ESI (±)-MS/MS. Total content of glucosinolates and isothiocyanates was measured via spectrophotometry. Myrosinase activity was monitored via spectrophotometry and/or UPLC-QqQ-(±) ESI. Cauliflower accumulated the highest quantity of iberin while Brussels sprouts and cabbage yielded the highest content of allyl isothiocyanate, respectively. On the other hand, broccoli, radish and Napa cabbage exhibited the highest content in sulforaphane whereas papaya exhibited almost exclusively benzyl isothiocyanate. The rate of myrosinase-induced bioconversion of glucosinolates into isothiocyanates depended on the yield of the reaction and the activity levels of myrosinase. Profiling of glucosinolates, isothiocyanates and their bioconversion rates in Brassicaceae and order Brassicales vegetable superfamilies demonstrate their nutritional value in health promotion and/or disease prevention strategies. • Targeted UPLC-QqQ-ESI (±)-MS/MS based-profiling of glucosinolates and isothiocyanates. • Comparative assessment of myrosinase-induced isothiocyanates’ formation. • Nutritional ranking of Brassicaceae based on bioactive metabolite yield. • Species-dependent enzyme-substrate effects on glucosinolates’ conversion. • Evaluation of functional potential of Brassicaceae and order Brassicales vegetables.
Kyriakou et al. (Sun,) studied this question.