Functional activities and biosynthesis of isothiocyanates in <i>Moringa oleifera</i> Lam. and Brassicaceae: an update

Isothiocyanates, secondary metabolites primarily derived from cruciferous plants, are known for their distinct flavors in food and diverse biological activities such as anti-tumor, anti-diabetic, neuroprotective, antibacterial, anti-inflammatory, and antioxidant properties. They are extensively utilized in food, medicine, and agriculture. Moringa oleifera Lam. has recently been recognized as a new food resource and has attracted increasing research attention. This plant belongs to the Brassicales order and the Moringa family. It was found to contain biologically active isothiocyanates such as sulforaphane and 4-(<i>α</i>-<i>L</i>-rhamnopyranosyloxy)-benzyl isothiocyanate (MIC-1). Considering the low content of natural products and the related environmental issues caused by chemical synthesis, synthetic biology presents a promising approach for the sustainable and efficient production of these compounds. Recently, the biosynthetic pathways of isothiocyanates in many plants have been elucidated, which can promote the heterologous production of isothiocyanates through microbial fermentation. This review comprehensively examines the bioactivity, bioavailability, and biosynthetic pathways of M. oleifera Lam. isothiocyanates, alongside recent advancements in molecular biology techniques aimed at enhancing their yield. By elucidating the functional significance of isothiocyanates, this review aims to provide a comprehensive understanding of their role and to support further developments in their utilization in functional foods. It also proposes strategies for achieving high-yield production of these valuable compounds, offering insights that bridge theoretical knowledge with practical applications in the field.