Caffeine is a chemical compound found naturally in such foods as coffee beans, tea, cacao beans (chocolate), kola nuts, maté, and guarana. It is well known for its characteristic, intensely bitter taste, and as a stimulant of the central nervous system, heart, and respiration. It is also a diuretic. Caffeine is an alkaloid of the methylxanthine family, which also includes the similar compounds theophylline and theobromine. In its pure state it is an intensely bitter white powder. Its chemical formula is C8H10N4O2, its systematic name is 1,3,7-trimethylxanthine or 3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione.
Caffeine belongs to a group of chemicals called xanthines which include theophylline (used in the treatment of lung diseases like emphysema and asthma) and theobromine. Xanthines stimulate the nervous system and can cause people to feel restless, nervous or unable to fall asleep. Caffeine is exreted in urine as methylxanthine and methyluric acid as a product of metabolizing caffeine.
Caffeine is an effective stimulant of the central nervous system and in large amounts can produce undesirable side effects such as nervousness and insomnia, rapid and irregular heartbeats, elevated blood sugar and cholesterol levels, excess stomach acid, and heartburn. It is definitely a teratogen (produces deformed fetuses) in rats; the FDA has advised practitioners to counsel patients who are or may become pregnant to avoid or limit consumption of foods and drugs containing caffeine. Based on our incomplete knowledge of side reactions to caffeine, prudent use seems desirable for all consumers, male and female. The problem is particularly significant for children because the effects of caffeine are related to body weight of the consumer. Caffeine is also used as a food additive regulated by the Federal Food and Drug Administration (FDA). Food and beverage manufacturers are legally required to list caffeine on their products' label only when caffeine has been added. Caffeine naturally present in other ingredients used in the production process need not be on the label. For example, chocolate contains caffeine, so it may not be listed as an additive in candy bars. People who wish to avoid caffeine need to be aware of such natural, plant sources when making food choices.
Caffeine is found naturally in coffee, tea, and chocolate. Colas and some other soft drinks contain it. Caffeine also comes in tablet and capsule forms and can be bought without a prescription. Over-the-counter caffeine brands include No Doz, Overtime, Pep-Back, Quick-Pep, Caffedrine, and Vivarin. Some pain relievers, medicines for migraine headaches, and antihistamines also contain caffeine.
Caffeine is one of the world's most widely used drugs. Some anthropologists believe its use may date back to the Stone Age. Pharmacologically, caffeine is one of a group of stimulants called methylxanthine, or xanthine, that occur naturally in some plants. Beverages made from the nuts, seeds or leaves of these plants are major sources of natural caffeine, such as coffee, made from the Coffea arabica plant; soft drinks, like Coca Cola, made from Kola nuts; and tea made from the leaves of Thea sinensis. Cocoa, used to make chocolate, contains caffeine as well as theobromine, another xanthine.
Caffeine is thought to act on the brain by blocking adenosine receptors. Adenosine, when bound to receptors of nerve cells, slows down nerve cell activity; this happens, among other times, during sleep. The caffeine molecule, being similar to adenosine, binds to the same receptors but doesn't cause the cells to slow down; instead, the caffeine blocks the receptors and thereby the adenosine action. The resulting increased nerve activity causes the release of the hormone epinephrine, which in turn leads to several effects such as higher heart rate, increased blood pressure, increased blood flow to muscles, decreased blood flow to the skin and inner organs, and release of glucose by the liver. In addition, caffeine, similar to amphetamines, increases the levels of the neurotransmitter dopamine in the brain.
Caffeine is quickly and completely removed from the brain and, unlike other CNS stimulants or alcohol, its effects are short lived. In addition, caffeine does not negatively affect concentration or higher mental functions, and hence caffeinated drinks are often consumed in the course of work.
Synonyms: 1,3,7-trimethylxanthine, 1-methyltheobromine, 7-methyltheophylline, methyltheobromide, 3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione, 1,3,7-trimethyl-2,6-dioxopurine, theine, caffein, coffeine, thein, guaranine, No-doz, Eldiatric C, 1,3,7-trimethyl-2,6-dioxo-1,2,3,6-tetrahydropurine, caffenium, various other trade names
Use: Diuretic, widely-used additive in foods and drinks. Used in treatment of shock and heart disease. Occurs naturally in a variety of foodstuffs, including coffee beans, tea and cola nuts.
Molecular formula: C8H10N4O2
CAS No: 58-08-2