Abstract
Inactive glucoraphanin (GR) in broccoli is converted to the antioxidant, anti-inflammatory, and anti-bacterial sulforaphane (SF) by cruciferous vegetable enzyme myrosinase (Myr), or similar enzymes from specific gut bacteria; both sources have variable efficiency. The effects of exogenous Myr on the conversion efficiency of GR to SF was compared to gut microbial Myr-like activity. In a randomized, double-blind, crossover study, sixteen subjects (9 F: 7 M) received a single oral dose of GR in broccoli seed extract with Myr-containing mustard seed powder, or broccoli seed extract alone, both with ascorbic acid. GR + Myr, on average, doubled the bioavailability of SF (39.8 ± 3.1%) compared to GR alone (18.6 ± 3.1%), and increased the conversion rate in the first 8 h (25.4% ± 2.7%) compared to GR alone (8.0% ± 2.7) based on measurement of urinary metabolites. There were no differences in fecal bacterial communities after the single dose; however, four bacterial GR-converting genes significantly correlated with GR conversion (p < 0.0155). To our knowledge, this is the first human study to simultaneously investigate (1) a well-defined Myr source, (2) broccoli seeds as source of GR, (3) prediction of gut microbial responsiveness to GR.
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Data availability
Raw 16S rRNA bacterial sequence data (fastq files and metadata) is available from NCBI through BioProject Accession number PRJNA1189833.
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Acknowledgements
The authors thank Emelia Tremblay and Mazie Gordon at the University of Maine, for their help with microbial lab work, Benjamin and Timothy Hunt at the University of Maine for their work reviewing literature on GR converting genes, and Scott Leonard at Oregon State University for analyzing urine samples for nitrile content.
Funding
This project was supported by the USDA National Institute of Food and Agriculture through the Maine Agricultural & Forest Experiment Station: Hatch Project Numbers ME022329 (Ishaq) and ME022303 (Li); the National Institute of Health [Li and Ishaq; NIH/NIDDK 1R15DK133826-01]. Marissa Kinney and Lola Holcomb were supported by US National Science Foundation One Health and the Environment (OH&E): Convergence of Social and Biological Sciences NRT program grant DGE-1922560, and Lola Holcomb was supported by the UMaine Graduate School of Biomedical Science and Engineering. This study was primarily funded by Brassica Protection Products LLC, Baltimore, MD.
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AM, LH, JWF, DCN, AP, YL, SLI & GV conceived the study, analyzed and interpreted the data. AM, AP, YL, SLI & GV designed the experiments. AM, LH, JWF, AP, SLI, & GV wrote and edited the manuscript. LH, CO, CK, & MK performed the laboratory analyses.CO, DCN, & MK performed the clinical studies. RO, LH, and SLI performed statistical analyses. All authors read and approved the final manuscript.
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Angela Mastaloudis was employed by Brassica Protection Products, LLC., Jed W. Fahey was a consultant to Brassica Protection Products, LLC. Lola Holcomb, Camila Olson, David C. Nieman, Colin Kay, Robert O’Donnell, Alessandra Pecorelli, Marissa Kinney, Yanyan Li, Suzanne L. Ishaq, and Giuseppe Valacchi declare no conflicts of interest.
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Mastaloudis, A., Holcomb, L., Fahey, J.W. et al. Exogenous myrosinase from mustard seed increases bioavailability of sulforaphane from a glucoraphanin-rich broccoli seed extract in a randomized clinical study. Sci Rep (2026). https://doi.org/10.1038/s41598-026-39389-4
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DOI: https://doi.org/10.1038/s41598-026-39389-4
