Broccoli ingestion increases the glucosinolate hydrolysis activity of microbiota in the mouse gut

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.