Effects of dietary broccoli on human in vivo drug metabolizing enzymes: evaluation of caffeine, oestrone and chlorzoxazone metabolism

Ingestion of cruciferous vegetables may prevent chemically inducedcarcinogenesis by their influence on specific cytochrome P450enzymes (CYP) and phase II drug metabolizing enzymes in humansand rodents. Thus CYP enzymes are involved in transformationof procarcinogens, mutagens, steroid hormones and a large varietyof other endogenous and exogenous components. In order to learnmore about the influence of cruciferous vegetables on drug metabolizingenzymes in man two CYP enzymespreviously suggested to be inducedby vegetables were selected in an in vivo experiment in humans.Sixteen healthy non-smoking subjects, two females and 14 males,were exposed to three different types of diets and afterwardsassayed for CYP1A2 catalysed caffeine metabolites and for CYP2E1catalysed 6-hydroxylation of chlorzoxazone. Further, 2-hydroxyoestrone:16