4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone or nicotine-derived nitrosamine ketone (NNK) is a tobacco-specific nitrosamine. NNK is considered to be a carcinogen. NNK induces deleterious mutations in oncogenes and tumor suppression genes by forming DNA adducts, which could be considered as tumor initiation. Meanwhile, the binding of NNK to the nicotinic acetylcholine receptor promotes tumor growth by enhancing and deregulating cell proliferation, survival, migration, and invasion, thereby creating a microenvironment for tumor growth.

Menthone is a naturally occurring organic compound. It is found in oils of peppermint, Japanese mint, pennyroyal, Micromeria abyssinica benth, geranium and other oils. It is widely used as fragrances and flavors in the cosmetic, perfume, drug, and food industries. Menthone is a naturally occurring pesticide. Menthone and isomenthone were mild skin irritants and of low acute dermal toxicity in rabbits. Neither showed any sensitizing potential in volunteer studies with dilute solutions. In rats, menthone demonstrated a moderate to low acute oral toxicity. On repeated oral administration, menthone produced increases in liver, kidney and spleen weights of rats. Mutagenic activity was reported for menthone in the bacterium Salmonella typhimurium (Ames test) and in fruitflies.