4′-Bromoflavone is a highly effective inducer of phase II detoxification enzymes and has been identified as a potent agent in cancer chemoprevention.

4′-Bromoflavone significantly increases quinone reductase (QR) activity in murine hepatoma 1c1c7 cells at low concentrations (10 nM required for doubling activity) and enhances the α- and mu-isoforms of glutathione S-transferase in H4IIE rat hepatoma cells, without toxicity[1]. Additionally, it serves as a strong inhibitor of cytochrome P4501A1-mediated ethoxyresorufin-O-deethylase activity, exhibiting an inhibition concentration (IC50) of 0.86 μM. Importantly, in HepG2 or MCF-7 cells, 4′-Bromoflavone notably reduces the binding of activated benzo[a]pyrene to DNA[1], indicating its potential protective role against certain chemical-induced damages.

In short-term dietary studies, 4′-Bromoflavone is shown to increase QR activity and glutathione levels in rat liver, mammary gland, colon, stomach, and lung in a dose-dependent manner. In studies with female Sprague Dawley rats, 4′-Bromoflavone significantly increases QR activity (phase II enzyme)[1]. In DMBA-treated female Sprague Dawley rats, dietary administration of 4′-Bromoflavone (2000 and 4000 mg/kg of diet, from 1 week before to 1 week after DMBA) significantly inhibits the incidence and multiplicity of mammary tumors and greatly increases tumor latency[1].