Inhibition of carcinogen-induced pulmonary and mammary carcinogenesis by chalcone administered subsequent to carcinogen exposure.

A study of the capacity of chalcone to inhibit benzo[alpha]pyrene(BP)-induced carcinogenesis of the lungs and forestomach in female A/J mice and N-methyl-N-nitrosourea (MNU)-induced mammary carcinogenesis in female Sprague-Dawley rats has been carried out. Chalcone, 5 mg/g of diet, had a inhibitory effect on pulmonary adenoma formation (29%) and on mammary tumor formation (49%) when the compound was fed starting one week after final carcinogen administration. Chalcone did not inhibit forestomach tumor formation. In an additional study, chalcone started 4 weeks after MNU and fed for 3-week courses alternating with 3-week courses of control diet for the duration of the protocol also inhibited mammary tumor formation by 49%. The data showing that chalcone has inhibitory effects against both pulmonary and mammary carcinogenesis when given after carcinogen administration provides the basis for further investigations of this and possibly other chalcones as chemopreventive suppressing agents.