The nomenclature of alkaloids has not been systematized. Most alkaloids bear the suffix- ine and their names are derived in various ways: from the generic name of the plant, for example hydrastine from Hydrastis canadensis, from the specific plant name, for example cocaine from Erythroxylum. coca; from the common name of the drug common name of the drug yielding them, for example, ergotamine from ergot; for example, morphine from Morpheus, Greek god of dreams. only the pelleterine group is named for a person, P. J. Pelletier, who discovered a number of alkaloids in the third of the nineteenth century. Occurrence
Alkaloids are derived from both plants and animals, including marine organisms.
Plant-derived alkaloids
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Home >> Molecular Biology Dictionary >> Aldosterone - Alkaloid
Alkaloids often occur as salts of plant acids such as malic, meconic, and quinic acids. Some plant alkalodis are combined with sugars, for example, solanine in potato (Solanum tuberosum) and tomatine in tomato (Lycopersicum esculentum). Others occur as amides, for example, piperine from black pepper (piper nigrum), or as esters, for example, cocaine from coca leaves (Erythroxylum coca). Still other alkaloids occur as quaternary salts or tertiary amine oxides. Animal-derived alkaloids While most alkaloids have been isolated from plants, a large number have been isolated from animal sources. They occur in mammals, anurans (frogs, toads), salamanders, arthropods (ants, millipedes, ladybugs, beetles, butterflies), marine organisms, mosses, fungi, and certain bacteria. Samandarine has been isolated from the European fire salamander (Salamandra maculosa). Very toxic steroidal alkaloids occur in certain frogs and toads; for example, the Columbian arrowpoison frog (Phyllobates aurotaenia) produces a highly lethal venom containing batrachotoxin. The Canadian beaver (Castor fiberi) produces castoramine, and the scent gland of the musk deer (Moschus moschiferus) produces muscopyridine. The Southern fire ant (Solenopsis invicta),secretesa powerful venom containing a series of 2,6-dialkylpiperidines. The European millirede (Glomeris marginata) when provoked discharges a defensive secretion containing glomerine, aquinazolone. When.from Cinchona bark and various Cinchona species, and coniine from poison hemlock (Conium maculatum).. Other important alkaloids are colchicine. from the autumn crocus (Colchicum autumnale), caffeine from coffee, tea, kola, and mate, and nicotine from the tobacco plant (Nicotiana tabacum) and Aztec tobacco (N. rustica). . Animal-derived alkaloids While most alkaloids have been isolated from plants, a large number have been isolated from animal sources. They occur in mammals, anurans (frogs, toads), salamanders, arthropods (ants, millipedes, ladybugs, beetles, butterflies), marine organisms, mosses, fungi, and certain bacteria. Samandarine has been isolated from the European fire salamander (Salamandra maculosa). Very toxic steroidal alkaloids occur in certain frogs and toads; for example, the Columbian arrowpoison frog (Phyllobates aurotaenia) produces a highly lethal venom containing batrachotoxin. The Canadian beaver (Castorfiberi) produces castoramine, and the scent gland of the musk deer (Moschus moschiferus) produces muscopyridine. The Southern fire ant (Solenopsis invicta) secretes a powerful venom containing a series of 2,6-dialkylpiperidines. The European millipede (Glomeris marginata) when provoked discharges a defensive secretion containing glomerine, aquinazolone. When molested, the European ladybug secreates hemolymph at the joints to afford protection against predators; this hemolymph contains precoccinelline and its oxide, coccinelline. Certain species of butterflies elaborate pheromones derived from exogenous pyrrolizidine alkaloid precursors; the pyrrolizidine alkaloid occurs in the secretions of Lycorea ceres ceres and Danaus gilippus berenice, where it elicits olfactory-receptor responses in female antennae and serves as a chemical messenger that induces mating behaviour. Marine alkaloids have been isolated from marine organisms, both plant and animal. Of great interest are the alkaloids occuring in certain toxic dinoflagellates, such as Gonyaux tamarensis in the North Atlantic and G. canetanella in the saxitoxin, gonyautoxin-II, and gonyautoxin-III. These paralytic alkaloids also occur in the Alaska butter clam (saxidomus giganteus) and toxic mussels (Mytilus californianus). Tetrodotoxin, present in the ovaries and liver of the Japanese puffer fish (spheroids rubripes and S. vermicularis), in the Taiwanese goby fish (Gobius cringer), and in the California newt (Taricha torosa), is one of the most lethal low-molecular-weight toxins known. Isolation and purification Since few plant species produce only a single alkaloid, there is the problem of separating complex mixtures. The alkaloid mixture is usually extracted from the finely powdered plant material by percolation with some solvent such as chloroform, methylene chloride, or toluene, and filtered. The solution is extracted repeatedly first with dilute sulfuric or hydrochloric acid and, after basification, with an organic solvent. These extracts when evaporated yield different mixtures of alkaloids which may be further separated by column chromatography over alumina or silica gel, vacuum liquid chromatography, countercurrent distribution, centrifugally accelerated radial thin-layer. Chromatography, or preparative- layer chromatography. Eventually, it is possible to obtain compounds in a high state of purity. Biosynthesis. Of great interest to chemicals is the mode of alkaloids synthesis in plants. The biosynthesis of most alkaloids can be derived hypothetically, by using a few well-known chemical reactions, from such relatively simple precursors as phenylalanine, tyrosine, tryptophan, histidine, methionine, acetate units, terpene units, and amino acids such as anthranilic acid, lysine, and ornithine. A number of simple alkaloids have been synthesized from amino acid derivatives under physiological conditions: pelletierine is derived from the amino acid lysine, while cocaine and nicotine are derived from ornithine ((20). Many alkaloids, such as morphine, berberine, and emetine, incorporate a tetrahydroisoquinoline unit derived from tyrosine; and others, such as strychnine, quinine, reserpine, and camptothecin, are derived from tryptophan. The terpenoid and steroidal alkaloids, such as the diterpenoid alkaloid aconitine and the steroidal alkaloid tomatidine from the tomato, are likely derived from mevalonic acid lactone. Function or adrenaline, produced in most animal species by the adrenal medulla, is used as a bronchodilator and cardiac stimulat and to counter allergic reactions, anesthesia, and cardiac arrest |
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