A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive substances are considered carcinogens, but their carcinogenic activity is attributed to the radiation, for example gamma rays and alpha particles, which they emit. Common examples of non-radioactive carcinogens are inhaled asbestos, certain dioxins, and tobacco smoke. Although the public generally associates carcinogenicity with synthetic chemicals, it is equally likely to arise from both natural and synthetic substances. Carcinogens are not necessarily immediately toxic; thus, their effect can be insidious.
Nitrate is a polyatomic ion with the chemical formula NO−
3. Salts containing this ion are called nitrates. Nitrates are common components of fertilizers and explosives. Almost all inorganic nitrates are soluble in water. An example of an insoluble nitrate is bismuth oxynitrate.
The nitrite ion has the chemical formula NO−
2. Nitrite is widely used throughout chemical and pharmaceutical industries. The nitrite anion is a pervasive intermediate in the nitrogen cycle in nature. The name nitrite also refers to organic compounds having the –ONO group, which are esters of nitrous acid.
Sodium nitrite is an inorganic compound with the chemical formula NaNO2. It is a white to slightly yellowish crystalline powder that is very soluble in water and is hygroscopic. From an industrial perspective, it is the most important nitrite salt. It is a precursor to a variety of organic compounds, such as pharmaceuticals, dyes, and pesticides, but it is probably best known as a food additive used in processed meats and (in some countries) in fish products.
Snus is a tobacco product, originating from a variant of dry snuff in early 18th-century Sweden. It is placed between the upper lip and gum for extended periods, as a form of sublabial administration. Snus is not fermented. Although used similarly to American dipping tobacco, snus does not typically result in the need for spitting and, unlike naswar, snus is steam-pasteurized.
In organic chemistry, nitrosamines are organic compounds with the chemical structure R2N−N=O, where R is usually an alkyl group. They feature a nitroso group bonded to a deprotonated amine. Most nitrosamines are carcinogenic in nonhuman animals. A 2006 systematic review supports a "positive association between nitrite and nitrosamine intake and gastric cancer, between meat and processed meat intake and gastric cancer and oesophageal cancer, and between preserved fish, vegetable and smoked food intake and gastric cancer, but is not conclusive".
Toxication, toxification or toxicity exaltation is the conversion of a chemical compound into a more toxic form in living organisms or in substrates such as soil or water. The conversion can be caused by enzymatic metabolism in the organisms, as well as by abiotic chemical reactions. While the parent drug are usually less active, both the parent drug and its metabolite can be chemically active and cause toxicity, leading to mutagenesis, teratogenesis, and carcinogenesis. Different classes of enzymes, such as P450-monooxygenases, epoxide hydrolase, or acetyltransferases can catalyze the process in the cell, mostly in the liver.
1,4-Dioxane is a heterocyclic organic compound, classified as an ether. It is a colorless liquid with a faint sweet odor similar to that of diethyl ether. The compound is often called simply dioxane because the other dioxane isomers are rarely encountered.
Processed meat is considered to be any meat that has been modified in order to either improve its taste or to extend its shelf life. Methods of meat processing include salting, curing, fermentation, smoking, boiling, frying, and/or the addition of chemical preservatives. Processed meat is usually composed of pork or beef or, less frequently, poultry. It can also contain offal or meat by-products such as blood. Processed meat products include bacon, ham, sausages, salami, corned beef, jerky, hot dogs, lunch meat, canned meat, chicken nuggets, and meat-based sauces. Meat processing includes all the processes that change fresh meat with the exception of simple mechanical processes such as cutting, grinding or mixing.
Dimethylamine is an organic compound with the formula (CH3)2NH. This secondary amine is a colorless, flammable gas with an ammonia-like odor. Dimethylamine is commonly encountered commercially as a solution in water at concentrations up to around 40%. An estimated 270,000 tons were produced in 2005.
Nicotine-derived nitrosamine ketone (NNK) is one of the key tobacco-specific nitrosamines derived from nicotine. It plays an important role in carcinogenesis. The conversion of nicotine to NNK entails opening of the pyrrolidine ring.
N-Nitrosonornicotine (NNN) is a tobacco-specific nitrosamine produced during the curing and processing of tobacco.
In organic chemistry, nitroso refers to a functional group in which the nitric oxide group is attached to an organic moiety. As such, various nitroso groups can be categorized as C-nitroso compounds, S-nitroso compounds, N-nitroso compounds, and O-nitroso compounds.
Arecoline is a nicotinic acid-based mild parasympathomimetic stimulant alkaloid found in the areca nut, the fruit of the areca palm. It is an odourless oily liquid. It can bring a sense of enhanced alertness and energy along with mild feelings of euphoria and relaxation. The psychoactive effects are comparable to that of nicotine.
Smokeless tobacco is a tobacco product that is used by means other than smoking. Their use involves chewing, sniffing, or placing the product between gum and the cheek or lip. Smokeless tobacco products are produced in various forms, such as chewing tobacco, snuff, snus, and dissolvable tobacco products. Smokeless tobacco products typically contain over 3000 constituents. All smokeless tobacco products contain nicotine and are therefore highly addictive. Quitting smokeless tobacco use is as challenging as smoking cessation.
In molecular genetics, a DNA adduct is a segment of DNA bound to a cancer-causing chemical. This process could lead to the development of cancerous cells, or carcinogenesis. DNA adducts in scientific experiments are used as biomarkers of exposure. They are especially useful in quantifying an organism's exposure to a carcinogen. The presence of such an adduct indicates prior exposure to a potential carcinogen, but it does not necessarily indicate the presence of cancer in the subject animal.
Snuff is a type of smokeless tobacco product made from finely ground or pulverized tobacco leaves. It is snorted or "sniffed" into the nasal cavity, delivering nicotine and a flavored scent to the user. Traditionally, it is sniffed or inhaled lightly after a pinch of snuff is either placed onto the back surface of the hand, held pinched between thumb and index finger, or held by a specially made "snuffing" device.
N-Nitrosodimethylamine (NDMA), also known as dimethylnitrosamine (DMN), is an organic compound with the formula (CH3)2NNO. It is one of the simplest members of a large class of N-nitrosamines. It is a volatile yellow oil. NDMA has attracted wide attention as being highly hepatotoxic and a known carcinogen in laboratory animals.
Tobacco-specific nitrosamines (TSNAs) comprise one of the most important groups of carcinogens in tobacco products, particularly cigarettes and fermented dipping snuff.
(+)-Benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide is an organic compound with molecular formula C20H14O3. It is a metabolite and derivative of benzo[a]pyrene (found in tobacco smoke) as a result of oxidation to include hydroxyl and epoxide functionalities. (+)-Benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide binds to the N2 atom of a guanine nucleobase in DNA, distorting the double helix structure by intercalation of the pyrene moiety between base pairs through π-stacking. The carcinogenic properties of tobacco smoking are attributed in part to this compound binding and inactivating the tumor suppression ability of certain genes, leading to genetic mutations and potentially to cancer.
