Aconitine is an alkaloid toxin produced by various plant species belonging to the genus Aconitum (family Ranunculaceae), known also commonly by the names wolfsbane and monkshood. Monkshood is notorious for its toxic properties.
Biologically active isolates from Aconitum and Delphinium plants are classified as norditerpenoidalkaloids,[1] which are further subdivided based on the presence or absence of the C18 carbon.[2] Aconitine is a C19-norditerpenoid, based on its presence of this C18 carbon. It is barely soluble in water, but very soluble in organic solvents such as chloroform or diethyl ether.[3][4] Aconitine is also soluble in mixtures of alcohol and water if the concentration of alcohol is high enough.
Like many other alkaloids, the basic nitrogen atom in one of the six-membered ring structure of aconitine can easily form salts and ions, giving it affinity for both polar and lipophilic structures (such as cell membranes and receptors) and making it possible for the molecule to pass the blood–brain barrier.[5] The acetoxyl group at the c8 position can readily be replaced by a methoxy group, by heating aconitine in methanol, to produce a 8-deacetyl-8-O-methyl derivatives.[6] If aconitine is heated in its dry state, it undergoes a pyrolysis to form pyroaconitine ((1α,3α,6α,14α,16β)-20-ethyl-3,13-dihydroxy-1,6,16-trimethoxy-4-(methoxymethyl)-15-oxoaconitan-14-yl benzoate) with the chemical formula C32H43NO9.[7][8]
Mechanism of action
Aconitine can interact with the voltage-dependent sodium-ion channels, which are proteins in the cell membranes of excitable tissues, such as cardiac and skeletal muscles and neurons. These proteins are highly selective for sodium ions. They open very quickly to depolarize the cell membrane potential, causing the upstroke of an action potential. Normally, the sodium channels close very rapidly, but the depolarization of the membrane potential causes the opening (activation) of potassium channels and potassium efflux, which results in repolarization of the membrane potential.
Aconitine binds to the channel at the neurotoxin binding site2 on the alpha subunit (the same site bound by batrachotoxin, veratridine, and grayanotoxin).[9] This binding results in a sodium-ion channel that stays open longer. Aconitine suppresses the conformational change in the sodium-ion channel from the active state to the inactive state. The membrane stays depolarized due to the constant sodium influx (which is 10–1000-fold greater than the potassium efflux). As a result, the membrane cannot be repolarized. The binding of aconitine to the channel also leads to the channel to change conformation from the inactive state to the active state at a more negative voltage.[10] In neurons, aconitine increases the permeability of the membrane for sodium ions, resulting in a huge sodium influx in the axon terminal. As a result, the membrane depolarizes rapidly. Due to the strong depolarization, the permeability of the membrane for potassium ions increases rapidly, resulting in a potassium reflux to release the positive charge out of the cell. Not only the permeability for potassium ions but also the permeability for calcium ions increases as a result of the depolarization of the membrane. A calcium influx takes place. The increase of the calcium concentration in the cell stimulates the release of the neurotransmitter acetylcholine into the synaptic cleft. Acetylcholine binds to acetylcholine receptors at the postsynaptic membrane to open the sodium-channels there, generating a new action potential.
Research with mouse nerve-hemidiaphragm muscle preparation indicate that at low concentrations (<0.1μM) aconitine increases the electrically evoked acetylcholine release causing an induced muscle tension.[11] Action potentials are generated more often at this concentration. At higher concentration (0.3–3μM) aconitine decreases the electrically evoked acetylcholine release, resulting in a decrease in muscle tension. At high concentration (0.3–3μM), the sodium-ion channels are constantly activated, transmission of action potentials is suppressed, leading to non-excitable target cells or paralysis.
Biosynthesis and total synthesis of related alkaloids
Aconitine is biosynthesized by the monkshood plant via the terpenoid biosynthesis pathway (MEP chloroplast pathway).[12] Approximately 700 naturally occurring C19-diterpenoid alkaloids have been isolated and identified, but the biosynthesis of only a few of these alkaloids are well understood.[13]
Likewise, only a few alkaloids of the aconitine family have been synthesized in the laboratory. In particular, despite over one hundred years having elapsed since its isolation, the prototypical member of its family of norditerpenoid alkaloids, aconitine itself, represents a rare example of a well-known natural product that has yet to succumb to efforts towards its total synthesis. The challenge that aconitine poses to synthetic organic chemists is due to both the intricate interlocking hexacyclic ring system that makes up its core and the elaborate collection of oxygenated functional groups at its periphery. A handful of simpler members of the aconitine alkaloids, however, have been prepared synthetically. In 1971, the Weisner group discovered the total synthesis of talatisamine (a C19-norditerpenoid).[14] In the subsequent years, they also discovered the total syntheses of other C19-norditerpenoids, such as chasmanine,[15] and 13-deoxydelphonine.[16]
Schematic for the Wiesner Syntheses of Napelline. Deoxydelphonine and Talatisamine
The total synthesis of napelline (Scheme a) begins with aldehyde100.[14] In a 7 step process, the A-ring of napelline is formed (104). It takes another 10 steps to form the lactone ring in the pentacyclic structure of napelline (106). An additional 9 steps creates the enone-aldehyde 107. Heating in methanol with potassium hydroxide causes an aldol condensation to close the sixth and final ring in napelline (14). Oxidation then gives rise to diketone 108 which was converted to (±)-napelline (14) in 10 steps.
A similar process is demonstrated in Wiesner's synthesis of 13-desoxydelphinone (Scheme c).[15] The first step of this synthesis is the generation of a conjugated dienone112 from 111 in 4 steps. This is followed by the addition of a benzyl vinyl ether to produce 113. In 11 steps, this compound is converted to ketal 114. The addition of heat, DMSO and o-xylene rearranges this ketol (115), and after 5 more steps (±)-13-desoxydelphinone (15) is formed.
Lastly, talatisamine (Scheme d) is synthesized from diene 116 and nitrile 117.[16] The first step is to form tricycle 118 in 16 steps. After another 6 steps, this compound is converted to enone120. Subsequently, this allene is added to produce photoadduct121. This adduct group is cleaved and rearrangement gives rise to the compound 122. In 7 steps, this compound forms 123, which is then rearranged, in a similar manner to compound 114, to form the aconitine-like skeleton in 124. A racemic relay synthesis is completed to produce talatisamine (13).
More recently, the laboratory of the late David Y. Gin completed the total syntheses of the aconitine alkaloids nominine[17] and neofinaconitine.[18]
Metabolism
Aconine: an amorphous, bitter, non-poisonous alkaloid, derived from the decomposition of aconitine
Aconitine is metabolized by cytochrome P450 isozymes (CYPs). There has been research in 2011 in China to investigate in-depth the CYPs involved in aconitine metabolism in human liver microsomes.[19] It has been estimated that more than 90 percent of currently available human drug metabolism can be attributed to eight main enzymes (CYP 1A2, 2C9, 2C8, 2C19, 2D6, 2E1, 3A4, 3A5).[20] The researchers used recombinants of these eight different CYPs and incubated it with aconitine. To initiate the metabolism pathway the presence of NADPH was needed. Six CYP-mediated metabolites (M1–M6) were found by liquid chromatography, these six metabolites were characterized by mass-spectrometry. The six metabolites and the involved enzymes are summarized in the following table:
Metabolite
Name
Involved CYPs
M1
O-Demethyl-aconitine
CYP3A4, CYP3A5, CYP2D6, CYP2C8
M2
16-O-Demethyl-aconitine
CYP3A4, CYP3A5, CYP2D6, CYP2C9
M3
N-deethyl-aconitine
CYP3A4, CYP3A5, CYP2D6, CYP2C9
M4
O-didemethyl-aconitine
CYP3A5, CYP2D6
M5
3-Dehydrogen-aconitine
CYP3A4, CYP3A5
M6
Hydroxyl-aconitine
CYP3A5, CYP2D6
Selective inhibitors were used to determine the involved CYPs in the aconitine metabolism. The results indicate that aconitine was mainly metabolized by CYP3A4, 3A5 and 2D6. CYP2C8 and 2C9 had a minor role to the aconitine metabolism, whereas CYP1A2, 2E1 and 2C19 did not produce any aconitine metabolites at all. The proposed metabolic pathways of aconitine in human liver microsomes and the CYPs involved to it are summarized in the table above.
Consuming as little as 2 milligrams of pure aconitine or 1 gram of the plant itself may cause death by paralyzing respiratory or heart functions.[23] Toxicity may occur through the skin; even touching the flowers can numb finger tips.[23][citation needed]
The toxic effects of aconitine have been tested in a variety of animals, including mammals (dog, cat, guinea pig, mouse, rat and rabbit), frogs and pigeons. Depending on the route of exposure, the observed toxic effects were local anesthetic effect, diarrhea, convulsions, arrhythmias or death.[23][24] According to a review of different reports of aconite poisoning in humans, the following clinical features were observed:[21]
Neurological: paresthesia and numbness of face, perioral area and four limbs; muscle weakness in four limbs
Progression of symptoms: the first symptoms of aconitine poisoning appear approximately 20 minutes to 2 hours after oral intake and include paresthesia, sweating and nausea. This leads to severe vomiting, colicky diarrhea, intense pain and then paralysis of the skeletal muscles. Following the onset of life-threatening arrhythmia, including ventricular tachycardia and ventricular fibrillation, death finally occurs as a result of respiratory paralysis or cardiac arrest.[25]
LD50 values for mice are 1mg/kg orally, 0.100mg/kg intravenously, 0.270mg/kg intraperitoneally and 0.270mg/kg subcutaneously. The lowest published lethal dose (LDLo) for mice is 1mg/kg orally and 0.100mg/kg intraperitoneally. The lowest published toxic dose (TDLo) for mice is 0.0549mg/kg subcutaneously. LD50 value for rats is 0.064mg/kg intravenously. The LDLo for rats is 0.040mg/kg intravenously and 0.250mg/kg intraperitoneally. The TDLo for rats is 0.040mg/kg parenterally. For an overview of more test animal results (LD50, LDLo and TDLo) see the following table.[24]
Species observed
Type of test
Route of exposure
Dose data (mg/kg)
Toxic effects
Human
LDLo
Oral
0.028
Behavioral: excitement
Gastrointestinal: hypermotility, diarrhea Gastrointestinal: other changes
Human
LDLo
Oral
0.029
Details of toxic effects not reported other than lethal dose value
Cat
LD50
Intravenous
0.080
Behavioral: convulsions or effect on seizure threshold
Cat
LDLo
Subcutaneous
0.100
Details of toxic effects not reported other than lethal dose value
Guinea pig
LD50
Intravenous
0.060
Behavioral: convulsions or effect on seizure threshold
Guinea pig
LDLo
Subcutaneous
0.050
Details of toxic effects not reported other than lethal dose value
Guinea pig
LDLo
Intravenous
0.025
Cardiac: arrhythmias (including changes in conduction)
Mouse
LD50
Intraperitoneal
0.270
Details of toxic effects not reported other than lethal dose value
Mouse
LD50
Intravenous
0.100
Sense Organs and Special Senses (Eye): lacrimation
Behavioral: convulsions or effect on seizure threshold Lungs, Thorax, or Respiration: dyspnea
Mouse
LD50
Oral
1
Details of toxic effects not reported other than lethal dose value
Mouse
LD50
Subcutaneous
0.270
Details of toxic effects not reported other than lethal dose value
Mouse
LDLo
Intraperitoneal
0.100
Details of toxic effects not reported other than lethal dose value
Mouse
LDLo
Oral
1
Behavioral: convulsions or effect on seizure threshold
Cardiac: arrhythmias (including changes in conduction) Gastrointestinal: hypermotility, diarrhea
Mouse
TDLo
Subcutaneous
0.0549
Peripheral Nerve and Sensation: local anesthetic
Behavioral: analgesia
Rabbit
LDLo
Subcutaneous
0.131
Details of toxic effects not reported other than lethal dose value
Rat
LD50
Intravenous
0.080
Behavioral: convulsions or effect on seizure threshold
Rat
LD50
Intravenous
0.064
Details of toxic effects not reported other than lethal dose value
Rat
LDLo
Intraperitoneal
0.250
Cardiac: other changes
Lungs, Thorax, or Respiration: dyspnea
Rat
LDLo
Intravenous
0.040
Cardiac: arrhythmias (including changes in conduction)
Rat
TDLo
Parenteral
0.040
Cardiac: arrhythmias (including changes in conduction)
Frog
LDLo
Subcutaneous
0.586
Details of toxic effects not reported other than lethal dose value
Pigeon
LDLo
Subcutaneous
0.066
Details of toxic effects not reported other than lethal dose value
Note that LD50 means lethal dose, 50 percent kill; LDLo means lowest published lethal dose; TDLo means lowest published toxic dose
For humans the lowest published oral lethal dose of 28 μg/kg was reported in 1969.
Diagnosis and treatment
For the analysis of the Aconitum alkaloids in biological specimens such as blood, serum and urine, several GC-MS methods have been described. These employ a variety of extraction procedures followed by derivatisation to their trimethylsilyl derivatives. New sensitive HPLC-MS methods have been developed as well, usually preceded by SPE purification of the sample.[25] The antiarrhythmic drug lidocaine has been reported to be an effective treatment of aconitine poisoning of a patient. Considering the fact that aconitine acts as an agonist of the sodium channel receptor, antiarrhythmic agents which block the sodium channel (Vaughan-Williams' classification I) might be the first choice for the therapy of aconitine induced arrhythmias.[26] Animal experiments have shown that the mortality of aconitine is lowered by tetrodotoxin. The toxic effects of aconitine were attenuated by tetrodotoxin, probably due to their mutual antagonistic effect on excitable membranes.[27] Also paeoniflorin seems to have a detoxifying effect on the acute toxicity of aconitine in test animals. This may result from alternations of pharmacokinetic behavior of aconitine in the animals due to the pharmacokinetic interaction between aconitine and paeoniflorin.[28] In addition, in emergencies, one can wash the stomach using either tannic acid or powdered charcoal. Heart stimulants such as strong coffee or caffeine may also help until professional help is available.[29]
Famous poisonings
During the Indian Rebellion of 1857, a British detachment was the target of attempted poisoning with aconitine by the Indian regimental cooks. The plot was thwarted by John Nicholson who, having detected the plot, interrupted the British officers just as they were about to consume the poisoned meal. The chefs refused to taste their own preparation, whereupon it was force-fed to a monkey who "expired on the spot". The cooks were hanged.
Aconitine was the poison used by George Henry Lamson in 1881 to murder his brother-in-law in order to secure an inheritance. Lamson had learned about aconitine as a medical student from professor Robert Christison, who had taught that it was undetectable—but forensic science had improved since Lamson's student days.[30][31][32]
Rufus T. Bush, American industrialist and yachtsman, died on September 15, 1890, after accidentally taking a fatal dose of aconite.
In 1953 aconitine was used by a Soviet biochemist and poison developer, Grigory Mairanovsky, in experiments with prisoners in the secret NKVD laboratory in Moscow. He admitted killing around 10 people using the poison.[33]
In 2004 Canadian actor Andre Noble died from aconitine poisoning. He accidentally ate some monkshood while he was on a hike with his aunt in Newfoundland.
In 2009 Lakhvir Singh of Feltham, west London, used aconitine to poison the food of her ex-lover Lakhvinder Cheema (who died as a result of the poisoning) and his current fiancée Gurjeet Choongh. Singh received a life sentence with a 23-year minimum for the murder on February 10, 2010.[34]
In 2022, twelve diners at a restaurant in York Region became acutely ill following a meal. All twelve became seriously ill and four of them were admitted to the intensive care unit after the suspected poisoning.[35]
In popular culture
Aconitine was a favorite poison in the ancient world. The poet Ovid, referring to the proverbial dislike of stepmothers for their step-children, writes:
Aconitine was also made famous by its use in Oscar Wilde's 1891 story "Lord Arthur Savile's Crime". Aconite also plays a prominent role in James Joyce's Ulysses, in which the father to protagonist Leopold Bloom used pastilles of the chemical to commit suicide. Aconitine poisoning plays a key role in the murder mystery Breakdown by Jonathan Kellerman (2016). In Twin Peaks (season 3) Part 13, aconitine is suggested to poison the main character.[37]
Monk's Hood is the name of the third Cadfael Novel written in 1980 by Ellis Peters. The novel was made into an episode of the television series Cadfael starring Derek Jacobi.
In the third season of the Netflix series You, two of the main characters poison each other with Aconite. One survives (due to a lower dose and an antidote), and the other is killed.
Hannah McKay (Yvonne Strahovski), a serial killer in the Showtime series Dexter uses Aconite on at least three occasions to poison her victims.
In season two episode sixteen of the series Person Of Interest aconitine is shown in a syringe stuck to the character Shaw (Sarah Shahi) nearly being injected and causing her death, until she is rescued by Reese (Jim Caviezel)
In a 2017 episode of The Doctor Blake Mysteries, fight manager Gus Jansons (Steve Adams) murdered his boxer, Mickey Ellis (Trey Coward), during a match by applying aconitine he had put in petroleum jelly and applying it to a cut over the boxer’s eye. He feared being blackmailed over a murder he helped cover up. He had made the poison from wolfsbane he had seen in a local garden.[38]
Cardiac glycosides are a class of organic compounds that increase the output force of the heart and decrease its rate of contractions by inhibiting the cellular sodium-potassium ATPase pump. Their beneficial medical uses are as treatments for congestive heart failure and cardiac arrhythmias; however, their relative toxicity prevents them from being widely used. Most commonly found as secondary metabolites in several plants such as foxglove plants, these compounds nevertheless have a diverse range of biochemical effects regarding cardiac cell function and have also been suggested for use in cancer treatment.
Aconitum, also known as aconite, monkshood, wolfsbane, leopard's bane, devil's helmet, or blue rocket, is a genus of over 250 species of flowering plants belonging to the family Ranunculaceae. These herbaceous perennial plants are chiefly native to the mountainous parts of the Northern Hemisphere in North America, Europe, and Asia, growing in the moisture-retentive but well-draining soils of mountain meadows.
Grayanotoxins are a group of closely related neurotoxins named after Leucothoe grayana, a plant native to Japan originally named for 19th century American botanist Asa Gray. Grayanotoxin I is also known as andromedotoxin, acetylandromedol, rhodotoxin and asebotoxin. Grayanotoxins are produced by Rhododendron species and other plants in the family Ericaceae. Honey made from the nectar and so containing pollen of these plants also contains grayanotoxins and is commonly referred to as mad honey. Consumption of the plant or any of its secondary products, including mad honey, can cause a rare poisonous reaction called grayanotoxin poisoning, mad honey disease, honey intoxication, or rhododendron poisoning. It is most frequently produced and consumed in regions of Nepal and Turkey as a recreational drug and traditional medicine.
Batrachotoxin (BTX) is an extremely potent cardio- and neurotoxic steroidal alkaloid found in certain species of beetles, birds, and frogs. The name is from the Greek word βάτραχος, bátrachos, 'frog'. Structurally-related chemical compounds are often referred to collectively as batrachotoxins. In certain frogs, this alkaloid is present mostly on the skin. Such frogs are among those used for poisoning darts. Batrachotoxin binds to and irreversibly opens the sodium channels of nerve cells and prevents them from closing, resulting in paralysis and death. No antidote is known.
The cardiac action potential is a brief change in voltage across the cell membrane of heart cells. This is caused by the movement of charged atoms between the inside and outside of the cell, through proteins called ion channels. The cardiac action potential differs from action potentials found in other types of electrically excitable cells, such as nerves. Action potentials also vary within the heart; this is due to the presence of different ion channels in different cells.
Solanine is a glycoalkaloid poison found in species of the nightshade family within the genus Solanum, such as the potato, the tomato, and the eggplant. It can occur naturally in any part of the plant, including the leaves, fruit, and tubers. Solanine has pesticidal properties, and it is one of the plant's natural defenses. Solanine was first isolated in 1820 from the berries of the European black nightshade, after which it was named. It belongs to the chemical family of saponins.
End plate potentials (EPPs) are the voltages which cause depolarization of skeletal muscle fibers caused by neurotransmitters binding to the postsynaptic membrane in the neuromuscular junction. They are called "end plates" because the postsynaptic terminals of muscle fibers have a large, saucer-like appearance. When an action potential reaches the axon terminal of a motor neuron, vesicles carrying neurotransmitters are exocytosed and the contents are released into the neuromuscular junction. These neurotransmitters bind to receptors on the postsynaptic membrane and lead to its depolarization. In the absence of an action potential, acetylcholine vesicles spontaneously leak into the neuromuscular junction and cause very small depolarizations in the postsynaptic membrane. This small response (~0.4mV) is called a miniature end plate potential (MEPP) and is generated by one acetylcholine-containing vesicle. It represents the smallest possible depolarization which can be induced in a muscle.
Cerberin is a type of cardiac glycoside, a steroidal class found in the seeds of the dicotyledonous angiosperm genus Cerbera; including the suicide tree and the sea mango. This class includes digitalis-like agents, channel-blockers that as a group have found historic uses as cardiac treatments, but which at higher doses are extremely toxic; in the case of cerberin, consumption of the C. odollam results in poisoning with presenting nausea, vomiting, and abdominal pain, often leading to death. The natural product has been structurally characterized, its toxicity is clear—it is often used as an intentional human poison in third-world countries, and accidental poisonings with fatalities have resulted from individuals even indirectly consuming the agent—but its potentially therapeutic pharmacologic properties are very poorly described.
Pseudaconitine, also known as nepaline (C36H51NO12), is an extremely toxic alkaloid found in high quantities in the roots of Aconitum ferox, also known as Indian Monkshood, which belongs to the family Ranunculaceae. The plant is found in East Asia, including the Himalayas.
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.
Anabasine is a pyridine and piperidine alkaloid found in the Tree Tobacco plant, as well as in the close relative of the common tobacco plant. It is a structural isomer of, and chemically similar to, nicotine. Its principal (historical) industrial use is as an insecticide.
Aconitum carmichaelii is a species of flowering plant of the genus Aconitum, family Ranunculaceae. It is native to East Asia and eastern Russia. It is commonly known as Chinese aconite, Carmichael's monkshood or Chinese wolfsbane. In Mandarin Chinese, it is known as fùzǐ and as wūtóu ; while in Japanese it is named torikabuto.
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. Early research was focused on identifying, and characterizing the properties of methyllycaconitine as 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. Most recently, it has become an important molecular probe for studying the pharmacology of the nicotinic acetylcholine receptor.
Pumiliotoxin 251D is a toxic organic compound. It is found in the skin of poison frogs from the genera Dendrobates, Epipedobates, Minyobates, and Phyllobates and toads from the genus Melanophryniscus. Its name comes from the pumiliotoxin family (PTXs) and its molecular mass of 251 daltons. When the toxin enters the bloodstream through cuts in the skin or by ingestion, it can cause hyperactivity, convulsions, cardiac arrest and ultimately death. It is especially toxic to arthropods, even at low concentrations.
Histrionicotoxins are a group of related toxins found in the skin of poison frogs from the family Dendrobatidae, notably Oophaga histrionica, which are native to Colombia. It is likely that, as with other poison frog alkaloids, histrionicotoxins are not manufactured by the amphibians, but absorbed from insects in their diet and stored in glands in their skin. They are notably less toxic than other alkaloids found in poison frogs, yet their distinct structure acts as a neurotoxin by non-competitive inhibition of nicotinic acetylcholine receptors.
Delphinine is a toxic diterpenoid alkaloid found in plants from the Delphinium (larkspur) and Atragene genera, both in the family Ranunculaceae. Delphinine is the principal alkaloid found in Delphinium staphisagria seeds – at one time, under the name stavesacre, a very well known herbal treatment for body lice. It is related in structure and has similar effects to aconitine, acting as an allosteric modulator of voltage gated sodium channels, and producing low blood pressure, slowed heart rate and abnormal heart rhythms. These effects make it highly poisonous. While it has been used in some alternative medicines, most of the medical community does not recommend using it due to its extreme toxicity.
Sodium ions are necessary in small amounts for some types of plants, but sodium as a nutrient is more generally needed in larger amounts by animals, due to their use of it for generation of nerve impulses and for maintenance of electrolyte balance and fluid balance. In animals, sodium ions are necessary for the aforementioned functions and for heart activity and certain metabolic functions. The health effects of salt reflect what happens when the body has too much or too little sodium. Characteristic concentrations of sodium in model organisms are: 10 mM in E. coli, 30 mM in budding yeast, 10 mM in mammalian cell and 100 mM in blood plasma.
The high-affinity choline transporter (ChT) also known as solute carrier family 5 member 7 is a protein in humans that is encoded by the SLC5A7 gene. It is a cell membrane transporter and carries choline into acetylcholine-synthesizing neurons.
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.
Dioscorine is an alkaloid toxin isolated from the tubers of tropical yam on several continents. It has been used as a monkey poison in some African countries, and as an arrow poison to aid in hunting in several parts of Asia. It was first isolated from Dioscorea hirsute by Boorsma in 1894 and obtained in a crystalline form by Schutte in 1897, and has since been found in other Dioscorea species. Dioscorine is a neurotoxin that acts by blocking the nicotinic acetylcholine receptor. Dioscorine is generally isolated in tandem with other alkaloids such as dioscin but is usually the most potent toxin in the mixture. It is a convulsant, producing symptoms similar to picrotoxin, with which it shares a similar mechanism of action.
References
↑ Biogenetically, aconitine is not a 'true' alkaloid, as it is not ultimately derived from amino acids. Aconitine is ultimately derived from isoprene, so it is technically a terpenoid and a pseudoalkaloid.
↑ Desai HK, Joshi BS, Ross SA, Pelletier SW (1989). "Methanolysis of the C-8 Acetoxyl Group in Aconitine-Type Alkaloids: A Partial Synthesis of Hokbusine A". Journal of Natural Products. 52 (4): 720–725. doi:10.1021/np50064a009.
↑ Gutser UT, Friese J, Heubach JF, Matthiesen T, Selve N, Wilffert B, Gleitz J (January 1998). "Mode of antinociceptive and toxic action of alkaloids of Aconitum spec". Naunyn-Schmiedeberg's Archives of Pharmacology. 357 (1): 39–48. doi:10.1007/pl00005136. PMID9459571. S2CID21509335.
↑ Benoit E (1998). "Mécanisme(s) d'action des neurotoxines agissant sur l'inactivation des canaux sodium activés par le potentiel de membrane" [Mechanism of action of neurotoxins acting on the inactivation of voltage-gated sodium channels]. Comptes Rendus des Séances de la Société de Biologie et de Ses Filiales (in French). 192 (3): 409–436. PMID9759381.
↑ Zhao PJ, Gao S, Fan LM, Nie JL, He HP, Zeng Y, Shen YM, Hao XJ (April 2009). "Approach to the biosynthesis of atisine-type diterpenoid alkaloids". Journal of Natural Products. 72 (4): 645–9. doi:10.1021/np800657j. PMID19275222.
1 2 Wiesner K, Tsai TY, Huber K, Bolton SE, Vlahov R (July 1974). "Total synthesis of talatisamine, a delphinine type alkaloid". Journal of the American Chemical Society. 96 (15): 4990–4992. doi:10.1021/ja00822a048.
↑ Tang L, Ye L, Lv C, Zheng Z, Gong Y, Liu Z (April 2011). "Involvement of CYP3A4/5 and CYP2D6 in the metabolism of aconitine using human liver microsomes and recombinant CYP450 enzymes". Toxicology Letters. 202 (1): 47–54. doi:10.1016/j.toxlet.2011.01.019. PMID21277363.
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↑ Jensen, Jeff (7 August 2017). "Twin Peaks recap: 'The Return: Part 13'". Entertainment Weekly. Meredith Corporation. Retrieved 4 May 2020. Clark offered to sell him Aconitine, a toxin with a rich literary history.
↑ December Media Pty. “A Lethal Combination.” The Doctor Blake Mysteries, Season 5, Episode 1. Australian Broadcasting Corporation, 17 September 2017.
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