Rhapontigenin is a mechanism-based, selective inactivator of cytochrome P450 1A1 (IC50: 400 nM), an aryl hydrocarbon hydroxylase which activates polycyclic aromatic hydrocarbons that act as procarcinogens. Rhapontigenin is a natural analog of resveratrol with antioxidant and anti-cancer activity. At higher concentrations, rhapontigenin inhibits the proliferation of HL-60R and HepG2 cancer cell lines (IC50: 48 μM).