quinine

quinine
Name	Quinine
IUPAC name	(R)-(6-methoxyquinolin-4-yl)((S)-quinolizidin-2-yl)methanol
Formula	C20H24N2O2
Molar mass	324.42 g·mol−1
CAS number	130-95-0
Density	1.26 g·cm−3
Melting point	173–176 °C
Solubility	sparingly soluble in water, soluble in ethanol

quinine

Quinine is a naturally derived alkaloid historically used as an antimalarial and flavoring agent. It was isolated from bark used by Indigenous peoples and entered European medicine during the early modern period, influencing colonial health practices and naval exploration. Studies spanning organic chemistry, pharmacology, and global public health have shaped modern understanding of its uses and limitations.

History

The medicinal use of cinchona bark reached Europe from Peru and Bolivia via Jesuit missionaries and merchants during the 17th century, intersecting with figures such as the Countess of Chinchón and institutions like the Casa de Contratación. The alkaloid was first extracted and characterized during the 19th century amid scientific activity in Paris and London, connecting laboratories led by chemists influenced by the Chemical Revolution and figures in the era of Louis Pasteur and Justus von Liebig. Demand for the bark drove colonial plantations in Java and British India under the administration of entities such as the Dutch East India Company and the British East India Company, while military campaigns in the Napoleonic Wars and later imperial expeditions highlighted quinine's role in protecting troops from malaria in tropical theaters like West Africa and Southeast Asia. The development of synthetic antimalarials in the 20th century, including investigations during World War II and research programs connected to institutions such as the Rockefeller Foundation and the National Institutes of Health, reduced reliance on quinine but preserved its historical significance in tropical medicine and global trade.

Chemical properties and synthesis

Quinine is an aromatic heterocyclic alkaloid whose structural elucidation was advanced by 19th-century organic chemists in laboratories across Germany and France. Its molecular framework includes a quinoline moiety and a quinuclidine-like bicyclic amine; features analogous to scaffolds studied by synthetic chemists such as Robert Burns Woodward and E. J. Corey. Total syntheses were milestones for research groups at institutions like Harvard University and Caltech, reflecting advances in stereoselective methods developed in the latter half of the 20th century. Physical properties—optical activity, melting point, and solubility—guided purification techniques in industrial settings managed by companies such as Bayer and historic firms in Basel. Chemical modifications to quinine's scaffold have been explored in medicinal chemistry programs at universities including Oxford University and University of Cambridge to derive analogues with altered pharmacokinetics.

Pharmacology and mechanism of action

Quinine's antimalarial activity was elucidated through parasitology and pharmacology work associated with laboratories at institutions like the London School of Hygiene & Tropical Medicine and the Pasteur Institute. It interferes with heme detoxification pathways in intraerythrocytic parasites such as species studied by scientists working on Plasmodium falciparum in collaboration with clinicians from hospitals including St Thomas' Hospital and research centers like the Centers for Disease Control and Prevention. Electrophysiological and binding studies at universities such as Johns Hopkins University and University of California, San Francisco revealed effects on ion channels and membrane potentials that account for cardiac and neuromuscular actions, informing safety evaluations by regulatory bodies including the Food and Drug Administration and the European Medicines Agency.

Medical uses and dosage

Clinically, quinine has been employed for severe malaria treatment in hospitals and military medical services, often compared with therapies derived from compounds researched at institutions like the Walter Reed Army Institute of Research and therapeutic strategies studied during the Vietnam War. Dosing regimens were established through trials coordinated by organizations such as the World Health Organization and national health ministries in countries like Ghana and Brazil. Quinine has also appeared as a component in tonic formulations linked historically to companies like Schweppes and administered under medical supervision in settings including intensive care units at major referral centers such as Mayo Clinic and Cleveland Clinic.

Adverse effects and contraindications

Adverse reaction profiles were catalogued in pharmacovigilance programs run by agencies including the Medicines and Healthcare products Regulatory Agency and the Pharmacovigilance Risk Assessment Committee. Notable toxicities—cinchonism featuring symptoms described in clinical reports from hospitals such as Guy's Hospital and Massachusetts General Hospital—include tinnitus, headache, visual disturbances, and gastrointestinal upset. Cardiotoxicity (arrhythmias), hypoglycemia seen in case series from clinics in Bangladesh and Nigeria, and hematologic effects such as thrombocytopenia prompted contraindications in patients with documented hypersensitivity or specific comorbidities managed at specialty centers like Royal Free Hospital. Interactions with drugs reviewed in formularies at institutions like Mount Sinai Hospital necessitate caution with agents affecting cardiac conduction or cytochrome P450 pathways, as monitored by professional societies including the Royal College of Physicians.

Sources, production, and regulation

Primary natural sources remain species of the genus Cinchona cultivated historically in plantations across Ecuador, Peru, Indonesia, and former colonies administrated by European trading companies. Commercial production has involved extraction methods developed by chemical engineers trained at universities such as Imperial College London and industrial chemistry firms located in regions like Basel and Rheinland-Pfalz. Regulation of quinine in pharmaceuticals, beverages, and exports engages agencies including the World Trade Organization for commodity standards, national regulators like the Health Canada and the Therapeutic Goods Administration for product approval, and international public health programs coordinated by the World Health Organization for treatment guidelines. Contemporary conservation and sustainable harvesting initiatives involve collaborations among NGOs and research institutions including the Smithsonian Institution and botanical gardens such as the Royal Botanic Gardens, Kew.

Category:Alkaloids Category:Antimalarial agents