Nicotine

L-(–)-Nicotine is a dinitrogen alkaloid that is present in concentrations as high as 3% in the dried leaves of the tobacco plant (Nicotiana tabacum). It exists in even higher concentrations (up to 14%) in the lesser known “Aztec tobacco” (N. rustica).

Nicotine is an unusual alkaloid in that it has two nitrogen-containing heterocycles, pyridine and pyrrolidine. It is, of course, the tobacco component that makes smoking highly addictive, leading to the consequence that long-term smoking causes cancer. The now-famous 1964 Report of the Advisory Committee to the Surgeon General of the United States brought widespread attention to the dangers of smoking.

In the modern era, much nicotine is delivered via e-cigarettes. Smokers have found that the nicotine in e-cigarettes is not as harsh to inhale as the one contained in tobacco.

A recent report by David H. Peyton and co-workers at Portland State University (Oregon) suggests why this is so: Nicotine in e-cigarettes is primarily in its protonated form rather than the free base that exists in tobacco. The authors infer that protonated nicotine is easier to inhale. Thus, if anything, e-cigarettes are likely to increase nicotine addiction

If you think nicotine is bad when you inhale it, take a look at its acute effects shown in the hazard information box.