After consuming broccoli, isothiocyanates can be produced by the hydrolytic action of myrosinase from plant and/or microbiota. Using male C57BL/6 mice, the present study investigated the effects of broccoli ingestion on the myrosinase-like activity, NAD(P)H:quinone oxidoreductase 1 (NQO1) activity, diversity and composition of the gut microbiota. Compared with the control group, continuously feeding raw or hydrolysed broccoli increased the myrosinase-like activities of the colon and caecum contents, and also improved the NQO1 activity of the colon mucosa. Significant difference between the broccoli and control feeding groups were found. 16S rRNA gene sequencing indicated that broccoli ingestion profoundly affected the composition of the gut bacteria community. The correlation between the gut bacterial community composition and microbiota myrosinase-like activity was also studied. However, one type of glucosinolate, sinigrin, had no effect on these activities, indicating that broccoli component(s), other than glucosinolate, had increased the NQO1 and myrosinase-like activities.

Broccoli by-products, traditionally considered inedible, possess a comprehensive nutritional and functional profile. These by-products are abundant in glucosinolates, particularly glucoraphanin, and sulforaphane, an isothiocyanate renowned for its potent antioxidant and anticarcinogenic properties. Broccoli leaves are a significant source of phenolic compounds, including kaempferol and quercetin, as well as pigments, vitamins, and essential minerals. Additionally, they contain proteins, essential amino acids, lipids, and carbohydrates, with the leaves exhibiting the highest protein content among the by-products. Processing techniques such as ultrasound-assisted extraction and freeze-drying are crucial for maximizing the concentration and efficacy of these bioactive compounds. Advanced analytical methods, such as high-performance liquid chromatography–mass spectrometry (HPLC-MS), have enabled precise characterization of these bioactives. Broccoli by-products have diverse applications in the food industry, enhancing the nutritional quality of food products and serving as natural substitutes for synthetic additives. Their antioxidant, antimicrobial, and anti-inflammatory properties not only contribute to health promotion but also support sustainability by reducing agricultural waste and promoting a circular economy, thereby underscoring the value of these often underutilized components.