Active Exogenous Myrosinase from Mustard Seed Increases Bioavailability of Sulforaphane from a Glucoraphanin-Rich Broccoli Seed Extract in a Human Clinical Study

Inactive glucoraphanin (GR) in broccoli can be converted to the antioxidant, anti-inflammatory, and anti-bacterial sulforaphane (SF) by cruciferous vegetable enzyme myrosinase (Myr), or similar enzymes from specific bacteria in the mammalian gut or fermented crucifers. The effects of exogenous Myr from mustard seed powder on the conversion efficiency of GR to SF was compared to gut microbial Myr-like activity. Sixteen subjects received a single oral dose of GR in broccoli seed extract with Myr-containing mustard seed powder, or broccoli seed extract. GR+Myr, on average, doubled the bioavailability of SF compared to GR alone, and increased the conversion rate in the first 8 h compared to GR alone based on measurement of urinary metabolites. There were no differences in fecal bacterial communities after the single dose; however, four known bacterial GR-converting genes significantly correlated with GR conversion.