Inhibition of the carcinogenic action of benzo(a)pyrene by flavones.

Abstract

A study of the effect of feeding flavone inducers of increased benzo(a)pyrene (BP) hydroxylase activity on pulmonary adenoma formation resulting from p.o. administration of BP to A/HeJ mice has been carried out. Three flavones have been used: β-naphthoflavone, a highly potent inducer; quercetin pentamethyl ether, intermediate in inducing potency; and rutin, a weak inducer. Administration of β-naphthoflavone resulted in almost total inhibition of pulmonary adenoma formation; with quercetin pentamethyl ether approximately 50% inhibition occurred, and with rutin there was no inhibition. In a second investigation, the effect of inducing increased BP hydroxylase activity in the skin of Ha/ICR mice on epidermal neoplasia initiated by BP was studied. Topical application of β-naphthoflavone resulted in slightly more than 50% inhibition of skin tumor formation.