Tobacco is a plant within the genus Nicotiana of the Solanaceae (nightshade) family. There are more than 70 species of tobacco. Products manufactured from dried tobacco leaves include cigars, cigarettes, snuff, pipe tobacco, chewing tobacco and flavored shisha tobacco. Other uses of tobacco include plant bioengineering and ornamentals, while chemical components of tobacco are used in some pesticides and medications.[1]
The chief commercial species, N. tabacum, is believed to have been native to tropical America, like most nicotiana plants, but has been so long cultivated that it is no longer known in the wild. N. rustica, a species producing fast-burning leaves, was the tobacco originally raised in Virginia, but it is now grown chiefly in Turkey, India, and Russia. The addictive alkaloid nicotine is popularly known as the most characteristic constituent of tobacco, but harmful effects of tobacco consumption can derive from the thousands of different chemicals in the smoke, including polycyclic aromatic hydrocarbons (such as benzopyrene), formaldehyde, cadmium, nickel, arsenic, tobacco-specific nitrosamines (TSNAs), phenols, and many others.[2] Tobacco also contains beta-carboline alkaloids which inhibit monoamine oxidase.[3]
Tobacco cultivation is similar to other agricultural products. Seeds are sown in cold frames or hotbeds to prevent attacks from insects, and then transplanted into the fields. Tobacco is an annual crop, which can be harvested mechanically or by hand. After harvest, tobacco is stored for curing, either by hanging, bundling or placing in large piles with tubular vents to allow the heat to escape from the center. Curing allows for the slow oxidation and degradation of carotenoids, causing the product to take on properties that are usually attributed to the "smoothness" of the smoke. Following this, tobacco is processed into its various forms for consumption. Most cigarettes incorporate flue-cured tobacco, which produces a milder, more...