Nicotine, a component of tobacco, is the primary reason that tobacco is addictive, although cigarette smoke contains many other dangerous chemicals, including tar, carbon monoxide, acetaldehyde, nitrosamines, and more.
Nicotine is an alkaloid which is found in the nightshade family of plants known as Solanaceae, and figures predominately in tobacco, and in lower quantities, in tomato, potato, eggplant, and green pepper. Nicotine alkaloids are also found in the leaves of the coca plant.
Nicotine constitutes 3 to 5% of the tobacco plant by dry weight, with biosynthesis taking place in the roots, and accumulates in the leaves. It is a potent neurotoxin and is included in many insecticides. In lower concentrations, the substance acts as a stimulant and is one of the main factors responsible for dependence-forming properties of tobacco smoking.
Nicotine is a hygroscopic, oily liquid that is miscible with water in its base form. As a nitrogenous base, nicotine forms slats with acids that are usually solid and water soluble. Nicotine easily penetrates the skin. The physical date shows that free base nicotine will burn at a temperature below its boiling point, and its vapors will combust at 95 degrees Centigrade in air despite a low vapor pressure. Because of this, most nicotine is burned when a cigarettes is smoked; however, enough is inhaled to provide the desired effects.
