Food matrix effects on bioactivity of broccoli-derived sulforaphane in liver and colon of F344 rats

Summary

This controlled dietary study in F344 rats examined how the food matrix—specifically whether sulforaphane was present as a purified compound, pre-formed in hydrolysed broccoli, or as intact glucosinolates—affected the bioactivity of this broccoli phytochemical as measured by Phase II enzyme (quinone reductase) induction. Whole broccoli containing intact glucosinolates proved more potent than either purified sulforaphane or pre-hydrolysed broccoli at inducing detoxification enzyme activity, despite containing substantially lower sulforaphane content, suggesting that food matrix components influence bioavailability and metabolic activation. The colon proved substantially more responsive than the liver to all dietary interventions.

Regional applicability

This animal feeding trial provides mechanistic evidence relevant to understanding sulforaphane bioactivity in human consumers of broccoli-containing diets. Direct application to United Kingdom dietary recommendations or health claims would require validation in human studies, though the findings underscore the potential importance of consuming whole broccoli rather than isolated phytochemical supplements.

Key measures

Quinone reductase activity (fold-increase over control) in liver and colon tissue; urinary sulforaphane-mercapturic acid levels

Outcomes reported

The study compared quinone reductase (QR) activity in liver and colon tissue of F344 rats fed purified sulforaphane, broccoli with pre-formed sulforaphane, or broccoli with intact glucosinolates over 5 days. Urinary sulforaphane metabolites and their correlation with QR activity were also measured.

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