This article is about the class of chemical compounds. For the pharmaceutical company, see Alkaloid (company).
Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral[2] and even weakly acidic properties.[3] Some synthetic compounds of similar structure may also be termed alkaloids.[4] In addition to carbon, hydrogen and nitrogen, alkaloids may also contain oxygen or sulfur. More rarely still, they may contain elements such as phosphorus, chlorine, and bromine.[5]
Alkaloids are produced by a large variety of organisms including bacteria, fungi, plants, and animals.[6] They can be purified from crude extracts of these organisms by acid-base extraction, or solvent extractions followed by silica-gel column chromatography.[7] Alkaloids have a wide range of pharmacological activities including antimalarial (e.g. quinine), antiasthma (e.g. ephedrine), anticancer (e.g. homoharringtonine),[8] cholinomimetic (e.g. galantamine),[9] vasodilatory (e.g. vincamine), antiarrhythmic (e.g. quinidine), analgesic (e.g. morphine),[10] antibacterial (e.g. chelerythrine),[11] and antihyperglycemic activities (e.g. berberine).[12][13] Many have found use in traditional or modern medicine, or as starting points for drug discovery. Other alkaloids possess psychotropic (e.g. psilocin) and stimulant activities (e.g. cocaine, caffeine, nicotine, theobromine),[14] and have been used in entheogenic rituals or as recreational drugs. Alkaloids can be toxic too (e.g. atropine, tubocurarine).[15] Although alkaloids act on a diversity of metabolic systems in humans and other animals, they almost uniformly evoke a bitter taste.[16]
The boundary between alkaloids and other nitrogen-containing natural compounds is not clear-cut.[17] Compounds like amino acid peptides, proteins, nucleotides, nucleic acid, amines, and antibiotics are usually not called alkaloids.[2] Natural compounds containing nitrogen in the exocyclic position (mescaline, serotonin, dopamine, etc.) are usually classified as amines rather than as alkaloids.[18] Some authors, however, consider alkaloids a special case of amines.[19][20][21]
^Luch, Andreas (2009). Molecular, Clinical and Environmental Toxicology, Volume 1: Molecular Toxicology. Vol. 1. Springer. p. 20. ISBN 9783764383367. OCLC 1056390214.
^ abIUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "alkaloids". doi:10.1351/goldbook.A00220
^Manske, R. H. F. (12 May 2014). The Alkaloids: Chemistry and Physiology, Volume 8. Vol. 8. Saint Louis: Elsevier. pp. 683–695. ISBN 9781483222004. OCLC 1090491824.
^Lewis, Robert Alan (23 March 1998). Lewis' Dictionary of Toxicology. CRC Press. p. 51. ISBN 9781566702232. OCLC 1026521889.
^"АЛКАЛОИДЫ - Химическая энциклопедия" [Alkaloids - Chemical Encyclopedia]. www.xumuk.ru (in Russian). Retrieved 18 May 2023.
^Roberts, M. F. (Margaret F.); Wink, Michael (1998). Alkaloids: Biochemistry, Ecology, and Medicinal Applications. Boston: Springer US. ISBN 9781475729054. OCLC 851770197.
^Gonçalves Paterson Fox, Eduardo; Russ Solis, Daniel; Delazari dos Santos, Lucilene; Aparecido dos Santos Pinto, Jose Roberto; Ribeiro da Silva Menegasso, Anally; Cardoso Maciel Costa Silva, Rafael; Sergio Palma, Mario; Correa Bueno, Odair; de Alcântara Machado, Ednildo (April 2013). "A simple, rapid method for the extraction of whole fire ant venom (Insecta: Formicidae: Solenopsis)". Toxicon. 65: 5–8. doi:10.1016/j.toxicon.2012.12.009. hdl:11449/74946. PMID 23333648.
^Kittakoop P, Mahidol C, Ruchirawat S (2014). "Alkaloids as important scaffolds in therapeutic drugs for the treatments of cancer, tuberculosis, and smoking cessation". Curr Top Med Chem. 14 (2): 239–252. doi:10.2174/1568026613666131216105049. PMID 24359196.
^Russo P, Frustaci A, Del Bufalo A, Fini M, Cesario A (2013). "Multitarget drugs of plants origin acting on Alzheimer's disease". Curr Med Chem. 20 (13): 1686–93. doi:10.2174/0929867311320130008. PMID 23410167.
^Raymond S. Sinatra; Jonathan S. Jahr; J. Michael Watkins-Pitchford (2010). The Essence of Analgesia and Analgesics. Cambridge University Press. pp. 82–90. ISBN 978-1139491983.
^Cushnie TP, Cushnie B, Lamb AJ (2014). "Alkaloids: An overview of their antibacterial, antibiotic-enhancing and antivirulence activities". Int J Antimicrob Agents. 44 (5): 377–386. doi:10.1016/j.ijantimicag.2014.06.001. PMID 25130096. S2CID 205171789.
^Singh, Sukhpal; Bansal, Abhishek; Singh, Vikramjeet; Chopra, Tanya; Poddar, Jit (June 2022). "Flavonoids, alkaloids and terpenoids: a new hope for the treatment of diabetes mellitus". Journal of Diabetes & Metabolic Disorders. 21 (1): 941–950. doi:10.1007/s40200-021-00943-8. ISSN 2251-6581. PMC 9167359. PMID 35673446.
^Robbers JE, Speedie MK, Tyler VE (1996). "Chapter 9: Alkaloids". Pharmacognosy and Pharmacobiotechnology. Philadelphia: Lippincott, Williams & Wilkins. pp. 143–185. ISBN 978-0683085006.
^Rhoades, David F (1979). "Evolution of Plant Chemical Defense against Herbivores". In Rosenthal, Gerald A.; Janzen, Daniel H (eds.). Herbivores: Their Interaction with Secondary Plant Metabolites. New York: Academic Press. p. 41. ISBN 978-0-12-597180-5.
^Robert A. Meyers Encyclopedia of Physical Science and Technology – Alkaloids, 3rd edition. ISBN 0-12-227411-3
^Cseke, Leland J.; Kirakosyan, Ara; Kaufman, Peter B.; Warber, Sara; Duke, James A.; Brielmann, Harry L. (19 April 2016). Natural Products from Plants. CRC Press. p. 30. ISBN 978-1-4200-0447-2.
^Johnson, Alyn William (1999). Invitation to Organic Chemistry. Jones & Bartlett Learning. p. 433. ISBN 978-0-7637-0432-2.
^Bansal, Raj K. (2003). A Textbook of Organic Chemistry. New Age International Limited. p. 644. ISBN 978-81-224-1459-2.
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