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

Lee Kellingray, Gwénaëlle Le Gall, Joanne F. Doleman, Arjan Narbad, Richard F. Mithen

Research output: Contribution to journalArticlepeer-review

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Abstract

Purpose:
Brassica are 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. Brassica and Allium plants also contain S-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 of Escherichia isolated 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 compound S-methylcysteine sulphoxide by bacteria isolated from human faeces.
Original languageEnglish
Pages (from-to)2141–2154
Number of pages14
JournalEuropean Journal of Nutrition
Volume60
Issue number4
Early online date16 Oct 2020
DOIs
Publication statusPublished - Jun 2021

Keywords

  • Broccoli
  • Glucosinolates
  • Short chain fatty acids
  • Lactobacilli
  • S-methylcysteine sulphoxide
  • Human gut microbiome

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