Quinine (redirected from Quinine powder)

quinine (kwī`nīn', kwĭnēn`), white crystalline alkaloid with a bitter taste. Before the development of more effective synthetic drugs such as quinacrine, chloroquine, and primaquine, quinine was the specific agent in the treatment of malaria. Almost insoluble in water, it dissolves readily in alcohol and other organic solvents. It is derived from the bark, called quina quina by the indigenous people of Peru, of several species of Cinchona and is used in the form of a salt, especially the sulfate. By the middle of the 17th cent. Jesuit missionaries had brought cinchona bark to Europe from South America, and quinine was isolated in 1820 by the French chemists J. B. Caventou and P. J. Pelletier; chemical synthesis was achieved in 1944 by R. B. Woodward and W. E. Doering, American chemists.

Certain strains of the malarial parasite Plasmodium falciparum have now developed a resistance to chloroquine, and quinine is again the preferred drug in some regions. Quinine also has been used medicinally to allay fever and pain, to induce uterine contractions during labor, and as a sclerosing, or hardening, agent in the treatment of varicose veins. It is added to soft drinks called tonics, which are often mixed with alcoholic beverages. Excessive dosage or continuous use of quinine may cause cinchonism, characterized by ringing in the ears, headache, dizziness, changes in blood pressure, and even death.

Bibliography

See F. Rocco, The Miraculous Fever-Tree (2003).

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quinine

Alkaloid found in the bark of cinchona trees and shrubs. The chemical structure of this heterocyclic compound is large and complex, with several rings. For the 300 years preceding the 1940s, when newer antimalarials were developed, quinine was the only drug known to Western medicine for the prevention and treatment of malaria. The first chemical compound ever used successfully against an infectious disease, it has benefited more people than any other such drug in history and is still used to treat malaria, often in combination with other drugs. Quinine is also a flavouring agent in some carbonated beverages, including tonic water.

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quinine

a bitter crystalline alkaloid extracted from cinchona bark, the salts of which are used as a tonic, antipyretic, analgesic, etc., and in malaria therapy. Formula: C₂₀H₂₄N₂O₂

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quinine [′kwī‚nīn]

(organic chemistry)

C₂₀H₂₄N₂O₂·3H₂O White powder or crystals, soluble in alcohol, ether, carbon disulfide, chloroform, and glycerol; an alkaloid derived from cinchona bark; used as an antimalarial drug and in beverages.

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Quinine 

an alkaloid found in the bark and other parts of trees of the genera Cinchona and Remijia of the family Rubiaceae, which grow in tropical countries. Quinine was first isolated in pure form in 1820 by the French chemists P. Pelletier and J. Caventou. It was successfully synthesized in 1944 by the American chemists R. Woodward and W. Doering.

In its chemical structure, quinine is a complex polycyclic compound. A base, it is poorly soluble in water but readily soluble in alcohol, ether, and chloroform.

Quinine is a typical protoplasmic poison. In therapeutic doses it affects various systems of the organism; quinine hydrochloride, quinine dihydrochloride, and quinine sulfate are used in medicine. Quinine depresses the heat-regulator centers. It reduces the excitability of the heart muscle, lengthens the refractory period, and somewhat decreases cardiac contractility. It stimulates the muscles of the uterus and increases its contraction. Because of its ability to depress the vital activities of the erythrocytic forms of malarial plasmodia, quinine is used as an antimalarial agent. In toxic doses, it depresses the activity of the cerebral cortex, leading to loss of hearing, vertigo, nausea, and other symptoms of poisoning.

In view of the difficulty in synthesizing quinine, it is isolated from the bark of the cinchona tree. The USSR imports very little quinine because of the production of effective Soviet synthetic antimalarial agents and the almost complete eradication of malaria.

V. V. PARIN