Since ancient times, people have used herbal ingredients to relieve pain and get rid of diseases and ailments. However, the study of the component composition, the isolation of those compounds that have such an effect, became possible only with the wide and massive development of chemistry as a science, that is, starting from the 17th century.
It was then in the bowels of plant organisms, and today already in some animals, that nitrogen-containing organic compounds were discovered, which gave such a wide therapeutic effect. Since 1819, the general name for this group of substances is alkaloids. Suggested by W. Meisner, pharmacist and physician.
What is an alkaloid?
It is currently accepted that an alkaloid is a cyclic compound containing one or more nitrogen atoms in the ring or side chain and, by its chemical nature, exhibits the properties of a weak alkali, like ammonia. Earlier it was said about the definition of these substances asderivatives of the nitrogenous base of pyridine. However, a number of compounds of this group were later discovered, which showed that such an interpretation is not entirely correct and does not cover the entire variety of alkaloids.
For the first time this substance was obtained and studied in 1803 by the scientist Derson. It was morphine, derived from opium. Subsequently, independently of each other, many scientists discovered a number of complex heterocyclic compounds from plant materials. So there was an idea that the alkaloid is a substance of predominantly natural origin. Formed only in plants.
Chemical composition of molecules
By their chemical nature, these substances are nitrogen-containing organic compounds that contain nitrogen atoms in complex heterocycles interconnected by different types of bonds and interactions.
From plants they stand out as s alts of certain acids:
- apple;
- wine;
- oxalic;
- acetic acid and others.
If a pure substance is separated from s alt, then an alkaloid can be obtained in the form of a solid crystalline powder, or it can be in the form of a liquid structure (nicotine). In both cases, it is an alkaline compound that exhibits the corresponding chemical properties.
That is, the chemistry of alkaloids is known and studied. For example, methods have been identified by which they can be isolated from plant materials. They are based on the solubility of alkaloid s alts in water, since in their pure form these compounds are almost insoluble in water, butdo it well in organic solvents.
A number of reactions by which these compounds are isolated and studied are called alkaloid reactions.
- Precipitation. Reactions based on the formation of an insoluble alkaloid s alt that precipitates. This can be done by using the following components: tannin, picric acid, phosphotungstic or molybdic acid.
- Precipitation. Reactions based on the formation of complex complex s alts with the participation of alkaloid compounds. Reagents: mercury chloride, potassium iodide or bismuth.
- Coloring. During these reactions, the form of the alkaloid changes and it becomes noticeable in the general composition. The principle of action is the effect on heterocycles, the appearance of color. Reagents: nitric acid, sulfuric acid, freshly precipitated copper (II) hydroxide.
Often staining reactions do not give accurate results, since the heterocyclic composition of alkaloids is similar to that of protein molecules. Therefore, they give the same effect.
Classification of alkaloids
What categories all known compounds of this group are divided into, determines the type of alkaloid, its chemical structure. Such a classification was created by Academician A. P. Orekhov and is based on the type and structure of the heterocycle with nitrogen atoms in them.
- Pyrrolidine, pyrrolizidine and their derivatives. This group includes such alkaloids as platifillin, sarracin, senecifylline and others. The structure is based on complex five-membered heterocycles connected to each other,which include a nitrogen atom.
- Piperidine and pyridine, their derivatives. Representatives: anabasin, lobelin. The basis is six-membered complex cycles with nitrogen.
- Quinolizidine and its compounds. This group includes: pahikarpin, thermopsin and others. Chemical base in complex six-membered heterocycles linked to each other and nitrogen.
- Quinoline derivatives - quinine, echinopsin.
- An important group of very common alkaloids are the isoquinoline compounds. Salsalin, morphine and papaverine are widely used in medicine. This also includes alkaloids in barberry plants, machka and celandine.
- Chemically very complex derivatives of tropane - hyoscyamine, atropine, scopolamine. The structure is represented by complexly condensed, intertwined pyrrolidine and piperidine rings.
- Indole and its compounds - reserpine, strychnine, vinblastine and others. A complex combination of five- and six-membered rings with nitrogen atoms in the structure.
- The main alkaloid in the food industry and medicine is caffeine from tea leaves and seeds of the cola plant. Refers to purine derivatives - complex compounds from different heterocycles and several nitrogen atoms in the composition.
- Ephedrine and its compounds - spherophysin, colchicine and colchamine. The chemical name for ephedrine, reflecting its complex structure, is phenylmethylaminopropanol, a complex organic aromatic alcohol.
- Recently, it is customary to isolate some substances of the steroid group - corticosteroids and sex hormones - into alkaloids.
Physical properties
The main properties of this group include the ability to dissolve in various liquids and the state of aggregation under standard conditions.
At room temperature, a common alkaloid is a crystalline solid. Colors and smells, as a rule, do not have. The taste is mostly bitter, astringent, unpleasant. Show optical activity in solutions.
Some of these substances under standard liquid conditions are oxygen-free alkaloids, about 200 species in total. For example, nicotine, pachycarpine, coniine.
If we talk about solubility in water, then only caffeine, ephedrine, ergometrine can do this completely. The remaining representatives of this class of compounds dissolve only in liquid organic substances (solvents).
Action on the human body
An alkaloid is a substance that has a strong effect on the human and animal body. What is this influence?
- Huge impact on the nervous system, nerve cell endings, synapses, neurotransmitter processes. Different groups of alkaloids act on these parts of the body as sedatives, psychotropic, reflex, antitussive, stimulants, narcotic drugs, analgesics. When used correctly for medical purposes, strictly dosed and accurately, these effects are beneficial. However, the slightest overdose can lead to very serious and sad consequences.
- Action on the cardio-vascular system - antiarrhythmic, improves blood supply, antispasmodic, hypotensive, choleretic.
In the event that alkaloid-based preparations are used inappropriately or without compliance with the required dosage, the following consequences are possible:
- impaired vision, hearing;
- breathing disorder, heaviness in chest;
- dizziness, nausea, vomiting;
- bleeding;
- dry mouth;
- a sharp increase or decrease in blood pressure;
- severe fatal poisoning.
A significant part of the alkaloids in their physiological effects on humans are poisons, strong, causing convulsions and death (strychnine, morphine, belladonnin). The other part is narcotic compounds that cause addiction. Psychological, emotional and physical (nicotine, caffeine, cocaine). Therefore, these compounds must be handled with extreme caution and used only on the advice and prescription of a physician.
Medical use
In this area, plants containing alkaloids are the basis for many drugs with a wide spectrum of action, or, conversely, highly specialized ones. On the basis of such raw materials, candles, tinctures, tablets, ampoule solutions are obtained. The action is aimed at the treatment of cardiovascular diseases, respiratory organs, nervous system and endings, mental disorders. Also for the treatment of the digestive system, as contraceptives, for oncological ailments, forelimination of alcohol addiction and many other areas.
Where are alkaloids found in nature?
In natural conditions, alkaloids contain medicinal herbs and plants. Today, about 10,000 names of these substances are known, and almost all of them are extracted from just such raw materials.
No alkaloids were found in parts of fungi, cells of bacteria, algae, echinoderms. Alkaloidal compounds have been extracted from the cells of some animals, but there are very few of them.
Thus, it turns out that the main supplier, an inexhaustible source of these substances for medical purposes, human life, and industry are plants containing alkaloids.
Medicinal plants
What are these plants? There are, in fact, too many to mention them all. However, you can name the most common and frequently used by man.
- Goosewort flat-leaved - alkaloid platifillin and senecifylline - antispasmodic and sedative effect on the body, used to create appropriate drugs.
- The common belladonna from the Solanaceae family. A very important plant for medicine. The belladonna alkaloid is atropine and belladonnin. Preparations based on belladonna components excite the central nervous system, activate mental and physical activity, increase efficiency and endurance. They have antispasmodic and analgesic effects. Medicinal drops, tinctures and suppositories are based on the extract of this plant.
- Black henbane. Fullypoisonous plant, all parts of it are dangerous. Alkaloids - hyoscyamine and scopolamine. Used to treat neurological ailments and seasickness.
- Celandine large. A very common plant in our country. However, it contains alkaloids quinolizidin, pachycarpine, saponin, thermopsin and others. Very poisonous if misused.
- Alkaloids in plants of the Poppy family are estimated at two dozen. These are opium, morphine, narcotine, papaverine, thebaine, codeine and other isoquinoline derivatives. We will consider their action and meaning separately.
- Passiflora meat red. Contains a number of alkaloids, derivatives of indole. Has a strong sedative effect.
- Argot. Specially created cultures of this parasitic fungus that destroys rye crops are used to obtain the strongest alkaloids. These are ergotamine and ergometrine, as well as 18 more varieties. Used in medicine (especially in gynecology).
- Rauwolfia serpentina - the roots of this plant contain more than 50 alkaloids used to treat cardiovascular diseases, including hypertension.
Medicinal herbs and plants are a very important field of modern medicine. After all, most of the drugs are synthesized on the basis of natural raw materials. They have been used since antiquity and have not lost their relevance to humans today. On the contrary, over time, people are increasingly striving to discover and study the composition of such plants in order to find something important, something that will help solve the problem of many incurable diseases.
The most common alkaloid
This is the derivative of opium - codeine. It can be isolated by special chemical reactions from morphine. Compared to the latter, it is safer to use, as it is soft in action. However, the effectiveness as an analgesic, antitussive, sedative is not worse than that of morphine or opium itself.
Therefore, codeine-based drugs are very widespread in medicine and are used by people of all countries. The only limitation is the dosage. It should be used only on the recommendation and under the supervision of a doctor.
Opium and its alkaloids
Opiates - so in medicine and chemistry it is customary to call all those opium alkaloids that can be isolated from it and synthesized on its basis. What are these connections? Unfortunately, today almost everyone hears about them and does not always have a good reputation and find a worthy, correct application. These are alkaloids such as:
- morphine;
- papaverine;
- heroin;
- codeine.
In medicine, these substances are used as antitussives, painkillers, sedatives. Based on codeine, a number of drugs have even been created for colds in children.
However, compounds such as opium and heroin are used not only for medical purposes, but also as heavy intoxicating drugs. They cause a terrible dependence of the human body and over time can cause serious harm to he alth, even people's lives.
