Study on Biological Defense Function though Regulation of Drug Metabolism System by Food Factors

（ PAHs ） are mediated mainly by the aryl hydrocarbon receptor （ AhR ） . Therefore, reduction of AhR activity is a promising strategy for prevention of xe-nobiotic-induced toxicity. Activation of nuclear factor-erythroid 2 -related factor 2 （ Nrf 2） results in enhanced antioxidant capacity and protection against environmental stressors by inducing phase II drug-metabolizing enzymes. The author revealed that luteolin and kaempferol coordinately prevent AhR-induced phase I drug-metabolizing enzyme, and a physiological concentration of luteolin, achievable from dietary consumption, activated Nrf 2 . Moreover, B[a]P-induced AhR activation caused lipid accumulation in the liver through circadian disruption; however, luteolin and kaempferol inhibited the circadian disruption caused by AhR activation. These results indicate that luteolin and kaempferol enhance biological defense function against xenobiotic-in-duced toxicity through the regulation of the drug metabolism system.