Laburnum alkaloid

Wink, M., Witte, L., Hartmann, T., Theuring, C. and Volz, V. 1983. Accumulation of quinolizidine alkaloids in plants and cell suspension cultures Genera Lupinus, Cytisus, Baptisia, Genista, Laburnum, and Sophora. Planta Medica, 48 253-257. 

Szentesi, A. and Wink, M. 1991. Fate of quinolizidine alkaloids through three trophic levels Laburnum anagyroides (Leguminosae) and associated organisms. Journal of Chemical Ecology, 17 1557-1573. 

Quinolizidine alkaloids are mainly found in plants of the Leguminosae/Fabaceae family. They deter or repel feeding of herbivores, and are toxic to them by a variety of mechanisms. A number of plants (Laburnum, Cytisus, Lupinus) containing significant quantities of these alkaloids must be regarded as potentially toxic to humans, and are known to be responsible for human poisoning. 

The widely planted and ornamental laburnum trees offer a particular risk, since all parts, including the pealike seeds, contain dangerously high amounts of alkaloids. So-called sweet lupins are selected strains with an acceptably low alkaloid content (typically about a quarter of the total alkaloids of bitter strains), which are grown as a high protein crop. 

An alkaloid found in all parts of the laburnum. Laburnum anagyroides (Leguminosae), particularly in the pods and seeds, and in some other leguminous plants. 

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. 

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. 

The lupin alkaloids are found in a wide variety of plants and small trees, such as broom, lupin, gorse, and laburnum, which are used diversely in gardens, for fodder, and as sand-binders. The alkaloids as a group are toxic, but as individuals find some use in veterinary medicine and in insecticide preparations. Chemical similarity rather than plant distribution links these alkaloids, since most of them contain—in actual or modified form—the quinolizidine ring structure (I). This basic... 

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. 

Nicotine-related alkaloids from dart-poison frogs, laburnum and cyanobacteria. 

Alkaloid occurring m laburnum (Cytisus laburmm, lann.), gorse, etc. M.p. 152-3°. Sol. HjO, EtOH, CHCI3, CJHj. Insol. CS, Et O, li oin, CCI4. Sublimes. [a] J — 119° in H O. Dist. with soda lime —pyrrole Red. with HI -f P —> cytisoliite. 

Besides avoiding, some insects can tolerate the defense chenustry of their host. The potato beetle Leptinotarsa decemlineata) lives on Solanum species containing steroidal alkaloids, which are tolerated but not stored by this species. The bruchid beetle, Bruchidius villosus, predates seeds of QA rich plants, such as Laburnum anagyroides. This beetle eliminates most of the dietary cystisine with the faces. Certain aphids can store the dietary alkaloids, for example, QA in Aphis cytisorum, A. genistae, and Macrosiphum albifrons and PA in Aphis jacobaeae and A. cacaliaster [70]. 

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). 

Quinohzidine alkaloids, hypothetically derived from quinolizidine (10-18), are a special group of bicyclic, tricyclic and tetracyclic secondary metabolites of some legumes, especially legumes of the genera Lupinus, Baptisia, Thermopsis, Genista, Cytisus, Chamae-cytisus. Laburnum and Sophora (Fabaceae), which occur as a complex mixture of several compounds. Quinolizidine alkaloids are... 

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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