Aporphine alkaloids are naturally occurring chemical compounds from the group of alkaloids. After the benzylisoquinoline alkaloids they are the second largest group of isoquinoline alkaloids.
At least 85 aporphine alkaloids have been isolated from plants of 15 families. The best known representative is apomorphine. The aporphine alkaloids are of interest mainly because of their similarity to morphine.
The aporphine alkaloids are most commonly found in plants. For example, isoboldine can be found in the plants in the genera Beilschmiedia , Nandina ( Nandina domestica ), Glaucium (horn poppy), and other plants. As the name suggests, glaucine was first found in the horn poppy and usually the name of the alkaloids is derived from the plants in which they were first found.
Corydin as a further representative of the aporphine alkaloids is found in Corydalis (larkspurs) Dicentra (heart flowers), and also in the horn poppy.
The aporphine alkaloids differ in their substituents and their position on the base structure. Furthermore, their stereochemistry is partly different; most often they are (R)-configured, but glaucine, bulbocapnine, and isothebaine, for example, are (S)-configured. [1]
The method by which the central aporphine ring structure is constructed in nature is exemplified by the biosynthesis of bulbocarpin. First, reticuline 1 is oxidized, resulting in a mesomery-stabilized diradical with the boundary structures 2a and 2b. Cyclization results in a fourth six-membered ring, corytuberin 3, which then dehydrates to bulbocapnin 4. [2]
The aporphine alkaloids are of particular interest because of their proximity to morphine and benzylisoquinoline alkaloids. For example, as the name suggests, morphine can be used to produce apomorphine. This can be done by adding an acid under the influence of heat.
The proaporphin alkaloids and the aporphin alkaloids share a framework isomerism.
The aporphine alkaloids usually have a stereocenter.
The (R)-configured glaucine can be synthesized from (S)-glaucine.
Apomorphine lowers blood pressure and is also a powerful emetic. It has been used to treat symptoms of Parkinson's disease because of its stimulating effect on dopamine receptors. [3]
Cassytha filiformis , a plant used in African traditional medicine, contains many aporphine alkaloids and that the three main alkaloids actinodaphnin, cassythin, and dicentrin have an in vitro effect on cancer cells. [4]
Morphine is a strong opiate that is found naturally in opium, a dark brown resin produced by drying the latex of opium poppies. It is mainly used as a pain medication, and is also commonly used recreationally, or to make other illicit opioids. There are numerous methods used to administer morphine: oral; sublingual; via inhalation; injection into a muscle, injection under the skin, or injection into the spinal cord area; transdermal; or via rectal suppository. It acts directly on the central nervous system (CNS) to induce analgesia and alter perception and emotional response to pain. Physical and psychological dependence and tolerance may develop with repeated administration. It can be taken for both acute pain and chronic pain and is frequently used for pain from myocardial infarction, kidney stones, and during labor. Its maximum effect is reached after about 20 minutes when administered intravenously and 60 minutes when administered by mouth, while the duration of its effect is 3–7 hours. Long-acting formulations of morphine are available as MS-Contin, Kadian, and other brand names as well as generically.
Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fungi, animals, or plants, which are not directly involved in the normal growth, development, or reproduction of the organism. Instead, they generally mediate ecological interactions, which may produce a selective advantage for the organism by increasing its survivability or fecundity. Specific secondary metabolites are often restricted to a narrow set of species within a phylogenetic group. Secondary metabolites often play an important role in plant defense against herbivory and other interspecies defenses. Humans use secondary metabolites as medicines, flavourings, pigments, and recreational drugs.
Papaver somniferum, commonly known as the opium poppy or breadseed poppy, is a species of flowering plant in the family Papaveraceae. It is the species of plant from which both opium and poppy seeds are derived and is also a valuable ornamental plant grown in gardens. Its native range was east of the Mediterranean Sea, but now is obscured by ancient introductions and cultivation, being naturalized across much of Europe and Asia.
Noscapine is a benzylisoquinoline alkaloid, of the phthalideisoquinoline structural subgroup, which has been isolated from numerous species of the family Papaveraceae. It lacks significant hypnotic, euphoric, or analgesic effects affording it with very low addictive potential. This agent is primarily used for its antitussive (cough-suppressing) effects.
Cassytha is a genus of some two dozen species of obligately parasitic vines in the family Lauraceae. Superficially, and in some aspects of their ecology, they closely resemble plants in the unrelated genus Cuscuta, the dodders. When fruit and flowers are absent in the field, the physical resemblance is so close that few people without technical training can discern the difference. In this respect and in their ecology the two genera present a spectacular example of convergent evolution. Nonetheless, Nickrent comments that "Cassytha is uneqivocally assigned to Lauraceae based on (both) morphological and molecular data." In its divergence from habits typical of the Lauraceae, Cassytha also presents examples of mosaic evolution
Apomorphine, sold under the brand name Apokyn among others, is a type of aporphine having activity as a non-selective dopamine agonist which activates both D2-like and, to a much lesser extent, D1-like receptors. It also acts as an antagonist of 5-HT2 and α-adrenergic receptors with high affinity. The compound is historically a morphine decomposition product made by boiling morphine with concentrated acid, hence the -morphine suffix. Contrary to its name, apomorphine does not actually contain morphine or its skeleton, nor does it bind to opioid receptors. The apo- prefix relates to it being a morphine derivative ("[comes] from morphine").
Aporphine is an alkaloid with the chemical formula C17H17N. It is the core chemical substructure of the aporphine alkaloids, a subclass of quinoline alkaloids. It can exist in either of two enantiomeric forms, (R)-aporphine and (S)-aporphine.
Glaucium flavum, the yellow horned poppy, yellow hornpoppy or sea poppy, is a summer flowering plant in the family Papaveraceae. It is native to Europe, Northern Africa, Macaronesia and temperate zones in Western Asia. The plant grows on the seashore and is never found inland. All parts of the plant, including the seeds, are toxic. It is classed as a noxious weed in some areas of North America, where it is an introduced species. It is grown in gardens as a short-lived perennial but usually grown as a biennial.
Bulbocapnine is an alkaloid found in Corydalis and Dicentra, genera of the plant family Fumariaceae which have caused the fatal poisoning of sheep and cattle. It has been shown to act as an acetylcholinesterase inhibitor, and inhibits biosynthesis of dopamine via inhibition of the enzyme tyrosine hydroxylase. Like apomorphine, it is reported to be an inhibitor of amyloid beta protein (Aβ) fiber formation, whose presence is a hallmark of Alzheimer's disease (AD). Bulbocapnine is thus a potential therapeutic under the amyloid hypothesis. According to the Dorlands Medical Dictionary, it "inhibits the reflex and motor activities of striated muscle. It has been used in the treatment of muscular tremors and vestibular nystagmus".
Nuciferine is an alkaloid found within the plants Nymphaea caerulea and Nelumbo nucifera.
Glaucine(1,2,9,10-TetraMethoxyAporphine, Bromcholitin, Glauvent, Tusidil, Tussiglaucin) is an aporphine alkaloid found in several different plant species in the family Papaveraceae such as Glaucium flavum, Glaucium oxylobum and Corydalis yanhusuo, and in other plants like Croton lechleri in the family Euphorbiaceae.
Pukateine is an alkaloid found in the bark of the New Zealand tree Laurelia novae-zelandiae ("Pukatea"), as well as some South American plants. An extract from pukatea is used in traditional Māori herbal medicine as an analgesic.
Higenamine (norcoclaurine) is a chemical compound found in a variety of plants including Nandina domestica (fruit), Aconitum carmichaelii (root), Asarum heterotropioides, Galium divaricatum, Annona squamosa, and Nelumbo nucifera.
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.
Substitution of the heterocycle isoquinoline at the C1 position by a benzyl group provides 1‑benzylisoquinoline, the most widely examined of the numerous benzylisoquinoline structural isomers. The 1-benzylisoquinoline moiety can be identified within numerous compounds of pharmaceutical interest, such as moxaverine; but most notably it is found within the structures of a wide variety of plant natural products, collectively referred to as benzylisoquinoline alkaloids. This class is exemplified in part by the following compounds: papaverine, noscapine, codeine, morphine, apomorphine, berberine, tubocurarine.
Nantenine is an alkaloid found in the plant Nandina domestica as well as some Corydalis species. It is an antagonist of both the α1-adrenergic receptor and the serotonin 5-HT2A receptor, and blocks both the behavioral and physiological effects of MDMA in animals.
Anonaine is a bioactive benzylisoquinoline alkaloid, present in members of the plant families Magnoliaceae and Annonaceae It is named after the plant it was first extracted from, Annona reticulata, which is commonly known as Anona.
Isoquinoline alkaloids are natural products of the group of alkaloids, which are chemically derived from isoquinoline. They form the largest group among the alkaloids.
The benzylisoquinoline alkaloids are natural products that can be classified as isoquinoline alkaloidss and are derived from benzylisoquinoline. They also include the benzyl(tetrahydro)isoquinoline alkaloids.