Evaluation of butylated hydroxyanisole, myo-inositol, curcumin, esculetin, resveratrol and lycopene as inhibitors of benzo[a]pyrene plus 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced lung tumorigenesis in A/J mice

The potential activities of butylated hydroxyanisole (BHA), myo-inositol, curcumin, esculetin, resveratrol and lycopene-enriched tomato oleoresin (LTO) as chemopreventive agents against lung tumor induction in A/J mice by the tobacco smoke carcinogens benzo[a]pyrene (BaP) and 4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) were evaluated. Groups of 20 A/J mice were treated weekly by gavage with a mixture of BaP and NNK (3 micromol each) for 8 weeks, then sacrificed 26 weeks after the first carcinogen treatment. Mice treated with BHA (20 or 40 micromol) by gavage 2 h before each dose of BaP and NNK had significantly reduced lung tumor multiplicity. Treatment with BHA (20 or 40 micromol) by gavage weekly or with dietary BHA (2000 ppm), curcumin (2000 ppm) or resveratrol (500 ppm) from 1 week after carcinogen treatment until termination had no effect on lung tumor multiplicity. Treatment with dietary myo-inositol (30,000 ppm) or esculetin (2000 ppm) from 1 week after carcinogen treatment until termination significantly reduced lung tumor multiplicity, with the effect of myo-inositol being significantly greater than that of esculetin. Treatment with dietary LTO (167, 1667 or 8333 ppm) from 1 week before carcinogen treatment until termination had no effect on lung tumor multiplicity. The results of this study demonstrate that BHA is an effective inhibitor of BaP plus NNK-induced lung tumorigenesis in A/J mice when administered during the period of carcinogen treatment and that, among the compounds tested, myo-inositol is most effective after carcinogen treatment.