Quinine is a crystalline alkaloid that is bitter in taste, whitish in color (or colorless), and needle-like in shape. Its IUPAC name is (R) - (6 – Methoxyquinolin – 4 - yl) ((2S, 4S, 8R) – 8 –vinylquinuclidin – 2 - yl) methanol. It is obtained from cinchona bark. At present, it has been synthesized in the laboratory. The medicinal property of the cinchona plant is traced back to the indigenous people of Peru and Bolivia.
Quinine is used as an alternative treatment for certain malarial diseases, particularly those that are resistant to pharmacological treatments. It was first found to be effective against Plasmodium falciparum in the 17th century. It used to be the drug of choice in treating malaria until chloroquine drug became available and preferred in the 1940s due to the latter's efficacy and fewer side effects.
Apart from antimalarial treatment, quinine was also used to treat lupus and arthritis. It has an analgesic (painkilling), anti-inflammatory, antipyretic, and cardiac depressant effects. It also reduces the excitability of the motor end plate. It is used as an ingredient of tonic water.