Dear Reader,
As we all know smoking is a nasty dirty habit, frankly it is ugly and very bad for your health. It has been known since the 1930s that smoking causes lung cancer, as a result the wretched smoke from evil herb has been examined with great care by scientists who are trying to work out the mechanism by which the ‘blacke stinking fume resembling the horrible Stigian smoke of the pit that is bottomelesse’ exerts its baneful effect on the cells in the human body.
I think that the great problem is that the smoke contains a range of different carcinogens, it contains cadmium oxide, polonium-210, benzopyrene and also N-nitrosoamines. The N-nitrosoamines are a very horrible class of carcinogens.
I was looking at a paper on the N-nitrosoamines associated with tobacco, one of the worst appears to be NNK [4-(methylnitrosamino)- 1-(3-pyridyl)-1-butanone] which is formed from nicotine. It has been shown by M. Sleiman, L.A. Gundel, J.F. Pankow, P. Jacob III, B.C. Singer and H. Destaillats in Proceedings of the National Academy of Sciences of the United States of America, 2010. In this paper it was shown that nicotine stains on surfaces react with nitrogen oxides from air pollution (and smoking) to form N-nitrosoamines such as NNK. Below is shown an example of how one of the N-nitrosoamines forms from nicotine.
Synthesis of NNK from nicotine by nitrous acid
One of the other ways in which NNK can form is by hydroxylation of nicotine. This is likely to be a free radical process, when I was out walking my dog I was thinking about this reaction. The reaction will be likely to start by the removal of a hydrogen atom from the carbon connected to both the nitrogen atom in the five memebered ring and the pyridine (six membered ring). I will write more about this free radical mechanism another day
Filed under: carcinogen Tagged: | cadmium oxide, cells in the human body, nicotine stains, nitrogen atom, nitrogen oxides
