Quinolizidine alkaloids are natural products that have a quinolizidine structure; this includes the lupine alkaloids. [1] [2] [3]
Quinolizidine alkaloids are natural products that have a quinolizidine structure; this includes the lupine alkaloids. [1] [2] [3]
Quinolizidine alkaloids can be found in the plant family of legumes, especially in papilionaceous plants. While the lupine alkaloids (following their name) can be found in lupines, tinctorin, for example, was isolated from the dyer's broom. [4] [1]
More than 200 quinolizidine alkaloids are known which can be classified into 6 structural types:
Cytisine is the toxic main alkaloid of laburnum. Similar to nicotine, it has a stimulating to hallucinogenic effect in low doses and a respiratory paralysing effect in higher doses. Cytisine and matrine are active ingredients of the Sophora beans from Mexico and the cow Seng and Shinkyogan drugs from China and Japan. [1]
Quinolizidine alkaloids defend plants against pests and diseases and breeding to reduce QA concentrations lowers these resistances. [5] They have various effects on warm-blooded animals and lead to poisoning of grazing livestock (sheep and cattle). Cytisin and anagyrin are particularly responsible for this. The effects of poisoning are stimulation, coordination disorders, shortness of breath, cramps and finally death from respiratory paralysis. Anagyrin acts teratogenic. The only quinolizidine alkaloid used therapeutically is sparteine, [2] which has an antiarrhythmic and labor-promoting effect. [1]
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 and even weakly acidic properties. Some synthetic compounds of similar structure may also be termed alkaloids. 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.
Aconitine is an alkaloid toxin produced by various plant species belonging to the genus Aconitum, commonly known by the names wolfsbane and monkshood. Aconitine is notorious for its toxic properties.
Strychnine is a highly toxic, colorless, bitter, crystalline alkaloid used as a pesticide, particularly for killing small vertebrates such as birds and rodents. Strychnine, when inhaled, swallowed, or absorbed through the eyes or mouth, causes poisoning which results in muscular convulsions and eventually death through asphyxia. While it is no longer used medicinally, it was used historically in small doses to strengthen muscle contractions, such as a heart and bowel stimulant and performance-enhancing drug. The most common source is from the seeds of the Strychnos nux-vomica tree.
Colchicine is a medication used to prevent and treat gout, to treat familial Mediterranean fever and Behçet's disease, and to reduce the risk of myocardial infarction. The American College of Rheumatology recommends colchicine, nonsteroidal anti-inflammatory drugs (NSAIDs) or steroids in the treatment of gout. Other uses for colchicine include the management of pericarditis.
Lupinus mutabilis is a species of lupin grown in the Andes, mainly for its edible bean. Vernacular names include tarwi, chocho, altramuz, Andean lupin, South American lupin, Peruvian field lupin, and pearl lupin. Its nutrient-rich seeds are high in protein, as well as a good source for cooking oil. However, their bitter taste has made L. mutabilis relatively unknown outside the Andes, though modern technology makes it easier to remove the bitter alkaloids. Like other species of lupin beans, it is expanding in use as a plant-based protein source.
Epibatidine is a chlorinated alkaloid that is secreted by the Ecuadoran frog Epipedobates anthonyi and poison dart frogs from the Ameerega genus. It was discovered by John W. Daly in 1974, but its structure was not fully elucidated until 1992. Whether epibatidine is the first observed example of a chlorinated alkaloid remains controversial, due to challenges in conclusively identifying the compound from the limited samples collected by Daly. By the time that high-resolution spectrometry was used in 1991, there remained less than one milligram of extract from Daly's samples, raising concerns about possible contamination. Samples from other batches of the same species of frog failed to yield epibatidine.
Tubocurarine is a toxic benzylisoquinoline alkaloid historically known for its use as an arrow poison. In the mid-1900s, it was used in conjunction with an anesthetic to provide skeletal muscle relaxation during surgery or mechanical ventilation. Safer alternatives, such as cisatracurium and rocuronium, have largely replaced it as an adjunct for clinical anesthesia and it is now rarely used.
Lupinine is a quinolizidine alkaloid present in the genus Lupinus of the flowering plant family Fabaceae. The scientific literature contains many reports on the isolation and synthesis of this compound as well as a vast number of studies on its biosynthesis from its natural precursor, lysine. Studies have shown that lupinine hydrochloride is a mildly toxic acetylcholinesterase inhibitor and that lupinine has an inhibitory effect on acetylcholine receptors. The characteristically bitter taste of lupin beans, which come from the seeds of Lupinus plants, is attributable to the quinolizidine alkaloids which they contain, rendering them unsuitable for human and animal consumption unless handled properly. However, because lupin beans have potential nutritional value due to their high protein content, efforts have been made to reduce their alkaloid content through the development of "sweet" varieties of Lupinus.
Sparteine is a class 1a antiarrhythmic agent and sodium channel blocker. It is an alkaloid and can be extracted from scotch broom. It is the predominant alkaloid in Lupinus mutabilis, and is thought to chelate the bivalent metals calcium and magnesium. It is not FDA approved for human use as an antiarrhythmic agent, and it is not included in the Vaughan Williams classification of antiarrhythmic drugs.
Methyllycaconitine (MLA) is a diterpenoid alkaloid found in many species of Delphinium (larkspurs). In common with many other diterpenoid alkaloids, it is toxic to animals, although the acute toxicity varies with species. Methyllycaconitine was identified one of the principal toxins in larkspurs responsible for livestock poisoning in the mountain rangelands of North America. Methyllycaconitine has been explored as a possible therapeutic agent for the treatment of spastic paralysis, and it has been shown to have insecticidal properties. It has become an important molecular probe for studying the pharmacology of the nicotinic acetylcholine receptor.
Veratrum album, the false helleborine, white hellebore, European white hellebore, or white veratrum is a poisonous plant in the family Melanthiaceae. It is native to Europe and parts of western Asia.
Lobeline is a piperidine alkaloid found in a variety of plants, particularly those in the genus Lobelia, including Indian tobacco, Devil's tobacco, great lobelia, Lobelia chinensis, and Hippobroma longiflora. In its pure form, it is a white amorphous powder which is freely soluble in water.
Oleandrin is a cardiac glycoside found in the poisonous plant oleander. As a main phytochemical of oleander, oleandrin is associated with the toxicity of oleander sap, and has similar properties to digoxin.
Lupinus leucophyllus is a species of lupine known by the common name velvet lupine. It is native to western North America, where it grows in many types of mountain, prairie, and plateau habitat. It is a robust, branching, erect perennial herb growing up to 90 centimetres (35 in) tall. Each palmate leaf is divided into 7 to 11 leaflets up to 7 centimetres (2.8 in) long. The herbage is coated in white woolly fibers and stiff hairs. The inflorescence is dense raceme of many flowers, each around a centimeter long. The flower is purple in color, fading brown, the patch on the banner petal yellow or brownish. The pointed sepals and the back of the banner are hairy to woolly in texture.
Matrine is an alkaloid found in plants from the genus Sophora. It has a variety of pharmacological effects, including anti-cancer effects, as well as κ-opioid and μ-opioid receptor agonism.
Gelsemine (C20H22N2O2) is an indole alkaloid isolated from flowering plants of the genus Gelsemium, a plant native to the subtropical and tropical Americas, and southeast Asia, and is a highly toxic compound that acts as a paralytic, exposure to which can result in death. It has generally potent activity as an agonist of the mammalian glycine receptor, the activation of which leads to an inhibitory postsynaptic potential in neurons following chloride ion influx, and systemically, to muscle relaxation of varying intensity and deleterious effect. Despite its danger and toxicity, recent pharmacological research has suggested that the biological activities of this compound may offer opportunities for developing treatments related to xenobiotic or diet-induced oxidative stress, and of anxiety and other conditions, with ongoing research including attempts to identify safer derivatives and analogs to make use of gelsemine's beneficial effects.
Taxine alkaloids, which are often named under the collective title of taxines, are the toxic chemicals that can be isolated from the yew tree. The amount of taxine alkaloids depends on the species of yew, with Taxus baccata and Taxus cuspidata containing the most. The major taxine alkaloids are taxine A and taxine B although there are at least 10 different alkaloids. Until 1956, it was believed that all the taxine alkaloids were one single compound named taxine.
Anagyrine is a teratogenic alkaloid first isolated from Anagyris foetida in the year 1885 by French biologists Hardy and Gallois. A. foetida, the Stinking Bean Trefoil, is a highly toxic shrub native to the Mediterranean region, with a long history of use in folk medicine. In the year 1939 Anagyrine was found by James Fitton Couch to be identical to an alkaloid present in many species belonging to the plant genus Lupinus (lupins). The toxin can cause crooked calf disease if a cow ingests the plant during certain periods of pregnancy.
Mitragynine is an indole-based alkaloid and the most abundant active alkaloid in the Southeast Asian plant Mitragyna speciosa, commonly known as kratom. The total alkaloid concentration in dried leaves ranges from 0.5 to 1.5%. In Thai varieties, mitragynine is the most abundant component while 7-hydroxymitragynine is a minor constituent. In Malaysian kratom varieties, mitragynine is present at lower concentration. Such preparations are orally consumed and typically involve dried kratom leaves which are brewed into tea or ground and placed into capsules. Mitragynine consumption for medicinal and recreation purposes dates back centuries, although early use was primarily limited to Southeast Asian countries such as Indonesia and Thailand where the plant grows indigenously. Recently, mitragynine use has spread throughout Europe and the Americas as both a recreational and medicinal drug. While research into the effects of kratom have begun to emerge, investigations on the active compound mitragynine are less common.
Cholinergic blocking drugs are a group of drugs that block the action of acetylcholine (ACh), a neurotransmitter, in synapses of the cholinergic nervous system. They block acetylcholine from binding to cholinergic receptors, namely the nicotinic and muscarinic receptors.
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