Quinine

The chemical composition of quinine is C₂OH₂ 4N₂O₂H₂O. Quinine is derived from cinchona bark, and mixed with lime. The bark and lime mixture is extracted with hot paraffin oil, filtered, and shaken with sulfuric acid. This solution is neutralized with sodium carbonate. As the solution cools, quinine sulfate crystallizes out. To obtain pure quinine, the quinine sulfate is treated with ammonia. Crystalline quinine is a white, extremely bitter powder. The powdered bark can also be treated with solvents, such as toluene, or amyl alcohol to extract the quinine. Current biotechnology has developed a method to produce quinine by culturing plant cells. Grown in test tubes that contain a special medium that contains absorbent resins, the cells can be manipulated to release quinine, which is absorbed by the resin and then extracted. This method has high yields but is extremely expensive and fragile.

Medicinally, quinine is best known for its treatment of malaria. Quinine does not cure the disease, but treats the fever and other related symptoms. Pharmacologically, quinine is toxic to many bacteria and one-celled organisms, such as yeast and plasmodia. It also has antipyretic (fever-reducing), analgesic (pain-relieving), and local anesthetic properties. Quinine concentrates in the red blood cells and is thought to interfere with the protein and glucose synthesis of the malaria parasite. With treatment, the parasites disappear from the blood stream. Many malarial victims have a recurrence of the disease because quinine does not kill the parasites living outside the red blood cells. Eventually, the parasites make their way into the blood stream, and the victim has a relapse. Quinine is also used to treat myotonic dystrophy (muscle weakness, usually facial) and muscle cramps associated with early kidney failure. The toxic side effects of quinine, called Cinchonism, include dizziness, tinnitus (ringing in ears), vision disturbances, nausea, and vomiting. Extreme effects of excessive quinine use include blindness and deafness.

Quinine also has nonmedicinal uses, such as in preparations for the treatment of sunburn. It is also used in liqueurs, bitters, and condiments. The best known nonmedicinal use is its addition to tonic water and soft drinks. The addition of quinine to water dates from the days of British rule in India-quinine was added to water as a prevention against malaria. About 40% of the quinine produced is used by the food and drug industry, the rest is used medicinally. In the United States, beverages made with quinine may contain not more than 83 parts per million cinchona alkaloids.