Induction of the phase 2 response in mouse and human skin by sulforaphane-containing broccoli sprout extracts

Albena T. Dinkova-Kostova, Jed W. Fahey, Kristina L. Wade, Stephanie N. Jenkins, Theresa A. Shapiro, Edward J. Fuchs, Michelle L. Kerns, Paul Talalay (Lead / Corresponding author)

    Research output: Contribution to journalArticlepeer-review

    142 Citations (Scopus)


    The isothiocyanate sulforaphane was isolated from broccoli extracts in a bioactivity-guided fractionation as the principal and very potent inducer of cytoprotective phase 2 enzymes and subsequently shown to inhibit tumor development in animal models that involve various carcinogens and target organs. Because broccoli and broccoli sprouts are widely consumed, extracts obtained from them are viewed as convenient vehicles for sulforaphane delivery to humans. In relation to our current interest in devising strategies for protection against UV light-induced skin cancer, it was necessary to examine the safety and efficacy of topical application of sulforaphane-containing broccoli sprout extracts as single and multiple doses in both mice and humans. Topical application of an extract delivering 100 nmol sulforaphane/cm increased the protein levels of NAD(P)H:quinone oxidoreductase 1 (NQO1), glutathione S-transferase A1, and heme oxygenase 1, three representative phase 2 enzymes, in mouse skin epidermis. Quantitative assessment of the activity of NQO1 24 h after dosing showed increases of 1.5- and 2.7-fold after application of single and multiple (thrice, every 24 h) doses, respectively. A dose-escalation safety study in healthy human subjects revealed no adverse reactions when doses as high as 340 nmol of sulforaphane in the form of broccoli sprout extracts were applied topically to the center of a 1-cm-diameter circle drawn on the volar forearm. A subsequent efficacy study showed that despite the interindividual differences in basal levels, the enzyme activity of NQO1 in homogenates of 3-mm full thickness skin punch biopsies increased in a dose-dependent manner, with maximum increases of 1.5- and 4.5-fold after application of 150 nmol doses, once or three times (at 24 h-intervals), respectively, thus providing direct evidence for induction of the phase 2 response in humans.

    Original languageEnglish
    Pages (from-to)847-851
    Number of pages5
    JournalCancer Epidemiology Biomarkers and Prevention
    Issue number4
    Publication statusPublished - 1 Apr 2007

    ASJC Scopus subject areas

    • Epidemiology
    • Oncology


    Dive into the research topics of 'Induction of the phase 2 response in mouse and human skin by sulforaphane-containing broccoli sprout extracts'. Together they form a unique fingerprint.

    Cite this