A Natural Chalcone Cardamonin Inhibited Transformation of Aryl Hydrocarbon Receptor Through Binding to the Receptor Competitively

Scope

Chalcones are widely present in most plants and have various health beneficial functions. This study investigates the suppressive effect of 13 natural and synthetic chalcones on transformation of aryl hydrocarbon receptor (AhR) induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 3-methylcholanthrene (3-MC) in a cell-free system, Hepa-1c1c7 cells, and liver of ICR mice.

Methods and results

In the cell-free system, cardamonin dose-dependently inhibits AhR transformation. Chalcones with substitution on 2′ and/or 6′ position is important for the suppressive effect, while the substitution on 4′ position is negatively for the effect. Moreover, cardamonin and 2′-hydroxychalcone competitively inhibit the binding of [³H]-3-MC to the AhR. In Hepa-1c1c7 cells, cardamonin inhibits AhR transformation and expression of cytochrome P4501A1 (CYP1A1) in a dose-dependent manner through suppressing TCDD-induced phosphorylation of both AhR and AhR nuclear translocator, heterodimerization of them, and nuclear translocation of AhR. In the liver of mice, oral administered cardamonin also inhibits 3-MC-induced AhR translocation and expression of CYP1A1.

Conclusion

Among used chalcones, a natural chalcone cardamonin competitively binds to AhR and suppresses its transformation. Thus, cardamonin is an effective food factor for suppression of the dioxin-caused biochemical alterations and toxicities.