Metabolism of Sulforaphane in Humans: Supplements vs. Whole Foods

Abstract

Sulforaphane (SFN), an isothiocyanate derived from cruciferous vegetables has been studied extensively for its health benefits, including cancer prevention. Plant‐based food sources contain SFN's precursor, glucoraphanin (GFN), which must be hydrolyzed by myrosinase to yield SFN. Myrosinase is present within the plant, and a small amount is produced by certain gut bacteria. We have previously shown that subjects consuming a GFN supplement with inactivated myrosinase had significantly lower levels of SFN metabolites in plasma and urine than after consuming broccoli sprouts. These results suggest that the inactivation of the plant‐derived myrosinase results in a significant decrease in the bioavailability of SFN. The goal of the current study was to compare the bioavailability of a myrosinase‐treated broccoli sprout extract (BSE) supplement to broccoli sprouts with equivalent SFN potential. Subjects consumed either BSE or broccoli sprouts once in the morning (time 0) or twice during the day (time 0 and 12h). Plasma and urine SFN metabolites were measured using liquid chromatography tandem mass spectrometry (LC‐MS/MS) at 3, 6, 12, 24 and 48h following initial consumption. The effects of glutathione‐S‐transferase polymorphisms on SFN metabolism were also examined. This research will provide important information for using SFN in human clinical trials.Grant Funding Source: R01CA122906 & P01CA090890