|Jmol-3D images||Image 1|
|Molar mass||190.24 g/mol|
|Melting point||152-153 °C|
|Boiling point||218 °C at 2 mmHg|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
|(what is: / ?)|
Cytisine, also known as baptitoxine and sophorine, is a toxic alkaloid that occurs naturally in several plant genera, such as Laburnum and Cytisus of the family Fabaceae. Despite its toxicity (LD50 i.v., in mice ~2 mg/kg), it has been used medically to help with smoking cessation: it is less effective but much cheaper than similar products. Its molecular structure has some similarity to that of nicotine and it has similar pharmacological effects. Excessive doses can interfere with breathing and cause death.
Plant species that contain cytisine are found in several genera of the Faboideae subfamily of the Fabaceae family, including Laburnum, Anagyris, Thermopsis, Cytisus, Genista, Retama and Sophora. Cytisine is also present in Gymnocladus of the Caesalpinioideae subfamily.
Māmane (Sophora chrysophylla) can contain amounts of cytisine that are lethal to most animals. The palila (Loxioides bailleui, a bird), Uresiphita polygonalis virescens and Cydia species (moths), and possibly sheep and goats are not affected by the toxin for various reasons, and use māmane, or parts thereof, as food. U. p. virescens caterpillars are possibly able to sequester the cytisine to give themselves protection from getting eaten; they have aposematic coloration which would warn off potential predators.
Cytisine is an acetylcholine agonist, and has strong binding affinity for the nicotinic acetylcholine receptor. As a pharmaceutical preparation, it is available for the treatment of tobacco smoking. It is extracted from the seeds of Cytisus laborinum L. (Golden Rain acacia) and has been available in former socialist economy (FSE) countries for more than 40 years as an aid to smoking cessation under the brand name Tabex produced by the Bulgarian pharmaceutical company Sopharma AD. It was first marketed in Bulgaria in 1964 and then became widely available in FSE countries. The synthetic drug varenicline, which has some structural and pharmacological similarities to cytisine, was approved in 2006 as a smoking cessation drug.
In 2011, a randomized controlled trial with 740 patients found cytisine improved 12-month abstinence from nicotine from 2.4% with placebo to 8.4% with cytisine. A 2013 meta-analysis of eight studies demonstrated that cytisine has similar effectiveness to other smoking cessation drugs already licensed in the US.
Plants containing cytisine, including the common broom and mescalbean, have also been used recreationally. Positive effects are reported to include a mild intoxication and heightened awareness of color. However, this practice is not recommended, since negative side effects can include nausea, vomiting, convulsions, heart pain, headache and, in larger doses, even death via respiratory failure.
(-)-Cytisine, extracted from Laburnum anagyroides seeds was used as a starting material for the preparation of "(+)-sparteine surrogate," for the preparation of enantiomerically enriched lithium anions of opposite sterochemistry to those anions obtained from sparteine. 
5. ORGANIC SYNTHESES, 2006, 83, 141. "Synthesis of (+)-(1R,@S,9S)-11-Methyl-7,11-Diazatricyclo[7.3.1.02.7]tridecane, a (+)sparteine surrogate," DOI: 10.15227/orgsyn.083.0141
- The Merck Index, 10th Ed. (1983) p.402, Rahway: Merck & Co.
- Banko, P. C.; Cipollini, M. L.; Breton, G. W.; Paulk, E.; Wink, M.; Izhaki, I. (2002). "Seed chemistry of Sophora chrysophylla (mamane) in relation to diet of specialist avian seed predator Loxioides bailleui (palila) in Hawaii". Journal of Chemical Ecology 28 (7): 1393–410. doi:10.1023/A:1016248502927. PMID 12199503.
- West et al (2011). "Placebo-Controlled Trial of Cytisine for Smoking Cessation". NEJM 365 (13): 1193–1200. doi:10.1056/NEJMoa1102035. PMID 21991893.
- Hajek, McRobbie and Myers (25 Feb 2013). "Efficacy of cytisine in helping smokers quit: systematic review and meta-analysis". Thorax 68 (11): 1037–42. doi:10.1136/thoraxjnl-2012-203035. PMID 23404838.
- Shaman Australis Cytisine pharmacology and information on substance availability in various plants.
- Cytisine Is Cheap And Effective In Helping Smokers Quit Information on treatment of tobacco smoking
- Tabex official website