Cas No. [58-08-2] is a bitter,
white crystalline xanthine alkaloid that is a psychoactive stimulant
drug. Caffeine was discovered by a German chemist, Friedrich
Ferdinand Runge, in 1819. He coined the term kaffein, a chemical
compound in coffee, which in English became caffeine. Caffeine is also
part of the chemical mixtures and insoluble complexes guaranine found in
guarana, mateine found in mate, and theine found in non-herbal tea;
all of which contain additional alkaloids such as the cardiac stimulants
theophylline and theobromine, and often other chemicals such as
polyphenols which can form insoluble complexes with caffeine.
is found in varying quantities in the beans, leaves, and fruit of some
plants, where it acts as a natural pesticide that paralyzes and kills
certain insects feeding on the plants. It is most commonly consumed
by humans in infusions extracted from the cherries of the coffee plant
and the leaves of the tea bush, as well as from various foods and drinks
containing products derived from the kola nut. Other sources include
yerba mate, guarana berries, and the Yaupon Holly.
In humans, caffeine is a central nervous system (CNS) stimulant, having
the effect of temporarily warding off drowsiness and restoring
alertness. Beverages containing caffeine, such as coffee, tea, soft
drinks, and energy drinks enjoy great popularity. Caffeine is the
most widely consumed psychoactive substance, but unlike many other
psychoactive substances it is legal and unregulated in nearly all
jurisdictions. In North America, 90% of adults consume
caffeine daily. The U.S. Food and Drug Administration lists caffeine as
a "multiple purpose generally recognized as safe food substance".
Caffeine has diuretic properties, at least when administered in
sufficient doses to subjects who do not have a tolerance for it.
Regular users, however, develop a strong tolerance to this effect, and
studies have generally failed to support the common notion that
ordinary consumption of caffeinated beverages contributes significantly