A diagram with two panels, and a cartoon mouse in the middle. The cartoon mouse is eating broccoli, and a cartoon of the digestive tract is overlaid on the mouse's abdomen. Lines emanating from the broccoli point to the left panel, and show the compound glucoraphanin being converted into sulforaphane by the myrosinase enzyme. Lines emanating from the colon of the mouse point to the panel on the right, showing the same biochemical conversion by gut microbes.

Interplay of broccoli/broccoli sprout bioactives with gut microbiota in reducing inflammation in inflammatory bowel diseases

Sue IshaqLeave a comment

As part of her master’s of science thesis in 2022, Johanna Holman reviewed hundreds of journal articles on anti-inflammatory, health-promoting dietary compounds in broccoli and other vegetables or fruits, and how microbes in the digestive tract can transform inactive precursors from foods into those beneficial compounds.

A cartoon of three gastrointestinal tracts showing the locations of inflammation in ulcerative colitis, crohn's disease, or healthy tissue. At the bottom are cross-sections showing thickening of the intestinal wall in patients with Crohn's, and ulcers in patients with colitis.
Figure 1. Primary Inflammatory Bowel Disease presentations, ulcerative colitis (UC) and Crohn’s disease (CD), compared to a healthy colon. UC is limited to the colon and is characterized by pseudopolyps and haustra loss (smoothing and shortening of the colon). CD can occur anywhere in the GI tract and is characterized by fissures, muscle thickening, and “cobblestoning”, which is the unique bubbling of the interior wall.

This is part of a broader research collaboration on how glucoraphanin in broccoli sprouts can be made into sulforaphane, which acts as an anti-inflammatory in humans (work that has been funded by the Allen Foundation). Humans are unable to convert glucoraphanin to sulforaphane, and a small amount of this occurs naturally thanks to enzymes in the broccoli sprouts. But, certain gut microbes can make the conversion and this has helped resolve colitis and other symptoms in mice in laboratory trials (manuscripts in review, work that has been funded by the NIH).

A diagram with two panels, and a cartoon mouse in the middle. The cartoon mouse is eating broccoli, and a cartoon of the digestive tract is overlaid on the mouse's abdomen. Lines emanating from the broccoli point to the left panel, and show the compound glucoraphanin being converted into sulforaphane by the myrosinase enzyme. Lines emanating from the colon of the mouse point to the panel on the right, showing the same biochemical conversion by gut microbes.
Figure 2. (A) Glucoraphanin hydrolysis in the presence of plant myrosinase upon damage to the broccoli plant. Epithiospecifier protein preferentially converts glucoraphanin to sulforaphane-nitrile. (B) Glucoraphanin hydrolysis has been demonstrated by gut bacteria in the cecum and colon of mammals. Low pH environments favor conversion to sulforaphane-nitrile.

Interplay of Broccoli/Broccoli Sprout Bioactives with Gut Microbiota in Reducing Inflammation in Inflammatory Bowel Diseases.

Holman, J., Hurd, M., Moses, P.,  Mawe, G.,  Zhang, T., Ishaq, S.L., Li, Y. 2022. The Journal of Nutritional Biochemistry 113: 109238.

Abstract

Inflammatory Bowel Diseases (IBD) are chronic, reoccurring, and debilitating conditions characterized by inflammation in the gastrointestinal tract, some of which can lead to more systemic complications and can include autoimmune dysfunction, a change in the taxonomic and functional structure of microbial communities in the gut, and complicated burdens in a person’s daily life. Like many diseases based in chronic inflammation, research on IBD has pointed towards a multifactorial origin involving factors of the person’s lifestyle, immune system, associated microbial communities, and environmental conditions. Treatment currently exists only as palliative care, and seeks to disrupt the feedback loop of symptoms by reducing inflammation and allowing as much of a return to homeostasis as possible. Various anti-inflammatory options have been explored, and this review focuses on the use of diet as an alternative means of improving gut health. Specifically, we highlight the connection between the role of sulforaphane from cruciferous vegetables in regulating inflammation and in modifying microbial communities, and to break down the role they play in IBD.

Acknowledgements: The authors would like to thank Brigitte Lavoie (University of Vermont) and Grace Chen (University of Michigan), as well as undergraduate researchers Dorien Baudewyns (Husson University), Louisa Colucci (Husson University), and Joe Balkan (Tufts University), for their work on the laboratory research which forms the broader collaboration that led to the generation of this review. All authors have read and approved the final manuscript. This project was supported by the USDA National Institute of Food and Agriculture, Hatch Project Numbers ME0-22102 (Ishaq) and ME0-22303 (Li) through the Maine Agricultural & Forest Experiment Station, and USDA-NIFA-AFRI Foundational Program [Grant No. 2018-67017-27520]. It was also supported by NIH grant NOA R21AT011203 (Mawe).

Conflict of Interest: The authors declare no conflicts of interest.

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