Quinine, C20H24N2O2, is a natural alkaloid having antipyretic, antimalarial and analgesic properties. It was formerly used in the prevention of malaria until supplanted by its derivatives quinacrine , chloroquine , and primaquine . Quinine may still be used to treat resistant malaria, and to treat nocturnal leg cramps. It was also used in an attempt to treat people who had been infected by prions, but with only limited success.
The large scale use of Quinine as an prophylactic started around 1850, although it had been in use since the 17th century. It was originally derived from the bark of the Cinchona, an Amazonian tree. Quinine was isolated in 1820 by Pelletier and Caventou , and synthetical manufacturing was achieved in 1944.
Use of quinine in theraputic or excessive doses may cause cinchonism and even death (in excessive doses or rare cases). In very large doses quinine also acts as an abortifacient, or may cause birth defects, especially deafness.
Quinine is a flavour component of tonic water. According to tradition, the bitter taste of antimalarial quinine tonic led British colonials in India to mix it with gin, thus creating the Gin and Tonic cocktail.
However, even if this was the case, today's refreshing gin & tonic is a rather different drink from theirs: the quantity of quinine in a glass of modern-day tonic water is a fraction of that formerly used in treating malaria. In the US, for example, the FDA limits tonic water quinine to 83 ppm which is one half to one quarter the concentration used in therapeutic tonic.