Laburnum Cytisine

Cytisine Natural analog (extracted from laburnum flowers) of varenicline ... 

Cytisine (= Baptitoxine Laburnum anagyrmrks (laburnum) nAChR to evoke D release] nACh-R agonist - 0(432... 

Toxicity. Cytisine is a highly toxic alkaloid which resembles nicotine in its actions. Fatalities have occurred after the ingestion of laburnum seeds, but recovery is more usual. 

In a fatality due to the ingestion of laburnum seeds (estimated amount ingested 50 mg), a blood concentration of 6.8 ig/ml of cytisine was reported the stomach contained 23 laburnum pods (H. G. H. Richards and A. Stephens, ibid.). 

Labeled cadaverine and lysine when administered to Cytisus laburnum L. gave rise, in good yield, to cytisine and its JV-methyl derivative. The formation of iV-methylcytisine from cytisine is a secondary process and may be a detoxication mode. The elimination of C-2 as benzoic acid provided one fifth of the total activity. The formation of cytisine (VIII) from sparteine by degradation is a possibility. Nowacki and Byerrum 27-30) were unable to observe activity at C-2 of cytisine and arrived at other conclusions. In view of the ready conversion of angustifoline into epihydroxylupanine (31-33) the former was postulated as the precursor of the tetracyclic lupine bases (34). 

Cytamen cyanocobalamin. cytarabine [ban, inn. jan, usan] (cytarabine hydrochloride [usan] Ara C Cytosar Cytosar-U ) is an antimetabolite cytotoxic ANTICANCER and ANTIVIRAL AGENT isolated from the mushroom Xerocomm nigromaculatus. It works by interfering with pyrimidine synthesis. Clinically, it can be used sys-temically in anticancer treatment mainly of acute leukaemia, cytidine diphosphate choline dticoline. cytidine diphosphocholine dticoline. cytisine is an alkaloid with CNS STIMULANT, RESPIRATORY STIMULANT and psychoactive properties. It has been used clinically as a respiratory stimulant in Russia. It is a common cause of poisoning by the seeds of Cytisus laburnum. 

Laburnum anagyroides seeds, flowers, bark contain the highly toxic alkaloid, cytisine. Produce dilated pupils, gastro-intestinal upset and vomiting, weakness, inco-ordination, asphyxia, death. Rabbits and hares are apparently unaffected. 

Cytisine occurs in the seeds of Cytisus laburnum L. and other Leguminosae. 

Cytisine (12, 38). The ground tops and seeds of Laburnum vuLgare were air-dried and extracted in a soxhlet with 50 % aqueous ethanol to which had been added 2 % of acetic acid. The extract after concentration was cleared with lead acetate, concentrated, made alkaline with sodium hydroxide, and extracted six times with an equal volume of chloroform. This left only a trace of cytisine in the aqueous layer. When the chloroform was removed, the residual alkaloidal material crystallized in part. No clear-cut separation of components was accomplished by fractional crystallization of the free base or the crude picrate. The isolation of cytisine as the benzenesulfonyl derivative was effected according to the method of Ing (5), and benzenesulfonyl-cytisine was collected and recrystallized from ethanol as glistening prisms, m.p. 261 . Microchemical tests and picrate formation and identification were also used to establish the presence of cytisine in a particular plant. 

Whereas laburnum is well tolerated by goats, sheep and hares, its seeds are highly toxic especially for humans (cytisism). Cytisine, like nicotine, leads at low concentrations to the excitation ofthe peripheral sympathetic nerves. At higher doses, it paralyses the stimulus transmission to the vegetative innervated organs and the motor endplates of the neuromuscular junction in the somatic nerve system, especially that ofthe respiratory centre. 

Bojadschiewa, M. et al., New method for obtaining cytisine from seeds of Cytisus laburnum, Phar-... 

While for developing of simple piperidine alkaloids, e.g., pelletierine (Punica granatum), piperine (Piper nigrum et longum), and lobeline (Lobelia inflata), only one molecule of lysine is necessary, for quinolizidine alkaloids - e.g., lupinine (Lupinus luteus), sparteine of antiarrhythmic activity (Sarothamnus scoparius), and cytisine of respiratory stimulant effect (Laburnum species) - two molecules of lysines are indispensable. It was also proved that lycopodine (Lycopodium tristachyum, clubmoss) of quinolizidine structure has no polyketide origin, but it is a modified dimer of pelletierine, which, in turn, is derivable from lysine and acetate. 

The appropriate time in the biosynthesis for the methylation reaction to occur and, of course, the correct position of the methyl group in the molecule, have important influences on modifying the skeleton. This is particularly true for the isoquinoline skeleton, especially in alkaloids of the morphine and aporphine groups (see p. 204 for structures). Methylation is considered to be a type of detoxication reaction. Thus Pohm (1966) has observed that in seedlings of Cytisus laburnum with removed cotyledons, cultivated in appropriate feeding solution, addition of small amounts of cytisine was inhibitory, whereas 50 times as much methylcytisine had no effect. Moreover, it seemed that methylcytisine acted as a type of antagonist toward cytisine. Generally methylation is considered to diminish the reactivity of a compound (Mothes, 1965, 1966). 

Cytisine, methylcytisine, and anagyrine were obtained from Cytisus laburnum (Leguminosae). All parts of the plant are poisonous because of the cytisine. It is one of the Cytisus alkaloids (95, 96). 

O Brien convincingly showed that diamine 71 could be utilized as a (+)-spar-teine surrogate, thus leading to enantiomeric products (Scheme 13.12) [58], Diamine 71 could readily be prepared from the naturally available alkaloid cytisine (73, Scheme 13.13), which could be isolated from Laburnum anagyr-oides seeds (available in kg quantities) through a simple and high-yielding extraction procedure. 

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