Lack of the inhibitory effect of intragastrically administered capsaicin on NNK-induced lung tumor formation in the A.J mouse.

Capsaicin is the principal component in Capsicum fruits consumed by humans worldwide as a food additive. The tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is thought to be an important causative factor in human lung cancer. Dietary factors are reported to modify lung tumor formation in laboratory animals and in humans. In this study, NNK-induced lung tumor formation in female A/J mice given intragastric doses of capsaicin (5 mg/kg body wt) was compared to mice not receiving capsaicin. At the end of the 21 week study, mice treated with capsaicin had an average of 17.1 +/- 1.8 lung tumors/mouse while untreated mice had 19.6 +/- 2. There were 100% lung tumor bearers in each group. Capsaicin alone did not affect spontaneous formation of lung tumors. Our results do not support a possible chemoprotective effect of dietary capsaicin toward NNK-induced lung tumors in human smokers.