Effects of in vitro metabolism of a broccoli leachate, glucosinolates andS-methylcysteine sulphoxide on the human faecal microbiome

Purpose Brassicaare an important food source worldwide and are characterised by the presence of compounds called glucosinolates. Studies indicate that the glucosinolate derived bioactive metabolite sulphoraphane can elicit chemoprotective benefits on human cells. Glucosinolates can be metabolised in vivo by members of the human gut microbiome, although the prevalence of this activity is unclear.BrassicaandAlliumplants also containS-methylcysteine sulphoxide (SMCSO), that may provide additional health benefits but its metabolism by gut bacteria is not fully understood. Methods We examined the effects of a broccoli leachate (BL) on the composition and function of human faecal microbiomes of five different participants under in vitro conditions. Bacterial isolates from these communities were then tested for their ability to metabolise glucosinolates and SMCSO. Results Microbial communities cultured in vitro in BL media were observed to have enhanced growth of lactic acid bacteria, such as lactobacilli, with a corresponding increase in the levels of lactate and short-chain fatty acids. Members ofEscherichiaisolated from these faecal communities were found to bioconvert glucosinolates and SMCSO to their reduced analogues. Conclusion This study uses a broccoli leachate to investigate the bacterial-mediated bioconversion of glucosinolates and SMCSO, which may lead to further products with additional health benefits to the host. We believe that this is the first study that shows the reduction of the dietary compoundS-methylcysteine sulphoxide by bacteria isolated from human faeces.

Automated summary

This study investigates the bacterial-mediated bioconversion of glucosinolates and SMCSO using a broccoli leachate, showing enhanced growth of lactobacilli and increased levels of short-chain fatty acids in microbial communities cultured in the leachate. Escherichia isolates from these communities were found to bioconvert glucosinolates and SMCSO, potentially leading to additional health benefits for the host.