Alkaloids. Alkaloids Type of alkaloid crossword puzzle 4 letters

Since ancient times, people have used herbal ingredients to relieve pain and get rid of diseases and illnesses. However, the study of the component composition, the isolation of those compounds that have such an effect, became possible only with the widespread and massive development of chemistry as a science, that is, starting from the 17th century.

It was then that nitrogen-containing organic compounds were discovered in the depths of plant organisms, and today also in some animals, which gave such a wide therapeutic effect. Since 1819, the general name for this group of substances is alkaloids. Suggested by W. Meissner, pharmacist and physician.

What is an alkaloid?

It is currently generally accepted that an alkaloid is a cyclic compound containing one or more nitrogen atoms in the ring or side chain and, by chemical nature, exhibiting the properties of a weak alkali, like ammonia. Previously, we talked about defining these substances as derivatives of the nitrogenous base pyridine. However, later a number of compounds of this group were discovered, which showed that this interpretation is not entirely correct and does not cover the entire variety of alkaloids.

This substance was first obtained and studied in 1803 by the scientist Derson. It was morphine obtained from opium. Subsequently, independently of each other, many scientists discovered a number of complex plant materials. This is how the idea developed that an 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.

They are isolated from plants as salts of certain acids:

• apple;
• wine;
• sorrel;
• vinegar and others.

If the pure substance is separated from the salt, then the alkaloid can be obtained in the form of a solid crystalline powder, or in the form of a liquid structure (nicotine). In both cases, it is an alkaline compound that exhibits the appropriate chemical properties.

That is, the chemistry of alkaloids is known and studied. For example, methods have been determined by which they can be isolated from plant materials. They are based on the solubility of alkaloid salts in water, since in their pure form these compounds are almost insoluble in water, but they do this perfectly well in organic solvents.

A number of reactions by which such compounds are isolated and studied are called alkaloid.

1. Precipitation. Reactions based on the formation of an insoluble alkaloid salt, which precipitates. This can be done by using the following components: tannin, picric acid, phosphotungstic or molybdic acid.
2. Precipitation. Reactions based on the formation of complex complex salts involving alkaloid compounds. Reagents: potassium or bismuth iodide.
3. Coloring. During these reactions, the type of alkaloid changes and it becomes noticeable in the overall composition. The principle of action is the effect on heterocycles, the appearance of color. Reagents: nitric, sulfuric acid, (II) freshly precipitated.

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 are determined by the type of alkaloid and its chemical structure. This classification was created by Academician A.P. Orekhov and is based on the type and structure of the heterocycle with nitrogen atoms in them.

1. Pyrrolidine, pyrrolizidine and their derivatives. This group includes alkaloids such as platyphylline, sarracine, seneciphylline and others. The structure is based on complex five-membered heterocycles connected to each other, which include a nitrogen atom.
2. Piperidine and pyridine, their derivatives. Representatives: anabasine, lobeline. The basis is six-membered complex cycles with nitrogen.
3. Quinolizidine and its compounds. This group includes: pachycarpine, thermopsin and others. The chemical basis is in complex six-membered heterocycles connected to each other and nitrogen.
4. Quinoline derivatives - quinine, echinopsin.
5. An important group of very common alkaloids are isoquinoline compounds. Salsalin, morphine and papaverine are widely used in medicine. This also includes alkaloids in barberry, poppy and celandine plants.
6. Chemically very complex derivatives of tropane are hyoscyamine, atropine, and scopolamine. The structure is represented by complex condensed, intertwined pyrrolidine and piperidine rings.
7. Indole and its compounds - reserpine, strychnine, vinblastine and others. A complex combination of five- and six-membered rings with nitrogen atoms in the structure.
8. 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.
9. Ephedrine and its compounds - spherophysin, colchicine and colchamine. The chemical name of ephedrine, reflecting its complex structure, phenylmethylaminopropanol is a complex organic aromatic alcohol.
10. Recently, it has become common to isolate certain substances from the steroid group - corticosteroids and sex hormones - into alkaloids.

Physical properties

The main properties of this group include the ability to dissolve in different liquids and the state of aggregation under standard conditions.

At room temperature, a common alkaloid is a crystalline solid. As a rule, they have no color or smell. The taste is mainly bitter, astringent, and unpleasant. They exhibit 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, and ergometrine can do this completely. The remaining representatives of this class of compounds dissolve only in liquid organic substances (solvents).

Effect on the human body

An alkaloid is a substance that has a strong effect on the human and animal body. What impact does this have?

1. It has a huge impact on the nervous system, nerve cell endings, synapses, and neurotransmitter processes. Different groups of alkaloids act on these parts of the body as psychotropic, reflexive, 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.
2. Effect on the cardiovascular system - antiarrhythmic, improves blood circulation, antispasmodic, hypotensive, choleretic.

If drugs based on alkaloids are used for other purposes or without compliance with the required dosage, the following consequences are possible:

• visual impairment, hearing impairment;
• difficulty breathing, heaviness in the chest;
• dizziness, nausea, vomiting;
• bleeding;
• dry mouth;
• a sharp increase or decrease in blood pressure;
• severe poisoning with fatal outcome.

A significant part of alkaloids in their physiological effects on humans are poisons, strong, causing convulsions and death (strychnine, morphine, belladonnine). The other part is narcotic compounds that cause addiction. Psychological, emotional and physical (nicotine, caffeine, cocaine). Therefore, you need to be extremely careful with these compounds and use them only on the recommendation and prescription of a doctor.

Use in medicine

In this area, plants containing alkaloids are the basis for many broad-spectrum drugs, or, conversely, highly specialized ones. Based on such raw materials, candles, tinctures, tablets, and 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 cancer, to eliminate alcohol addiction and many other areas.

Under 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, bacterial cells, algae, or echinoderms. Compounds of alkaloid nature 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 kind of plants are these? There are, in fact, too many to mention all. However, we can name the most common and frequently used by humans.

Medicinal herbs and plants are a very important area of ​​modern medicine. After all, most of the drugs are synthesized on the basis of natural raw materials. They have been used since ancient times and have not lost their relevance for humans today. On the contrary, over time, people are increasingly striving to discover and study the component composition of such plants in order to find something important, something that will help solve the problem of many incurable diseases.

Most common alkaloid

This is considered to be an opium derivative - codeine. It can be isolated from morphine by special chemical reactions. Compared to the latter, it is safer to use, since it is mild in action. However, its effectiveness as an analgesic and sedative is no 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 only be used on the recommendation and under the supervision of a physician.

Opium and its alkaloids

Opiates - this is how 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 they are heard by almost everyone and do not always have a good reputation and find worthy, correct use. These are alkaloids such as:

• morphine;
• papaverine;
• heroin;
• codeine.

In medicine, these substances are used as antitussives, analgesics, and sedatives. A number of drugs have even been created based on codeine 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 terrible dependence on the human body and, over time, can cause serious harm to health, even to people’s lives.

text_fields

text_fields

arrow_upward

Currently, about 10,000 alkaloids have been discovered, of which about 4,000 have a proven structure. Such a huge number and diversity of alkaloids does not make it possible to develop a unified classification.

The classification of alkaloids can be based on different principles, therefore there are several types of classifications of alkaloids.

1. At the core pharmacological classification lies the nature of the pharmacological action of alkaloids on the body:

• narcotic alkaloids;
• local anesthetic alkaloids;
• antispasmodic alkaloids, etc.

2. At the core botanical classification lies the systematic affiliation of plants from which alkaloids are isolated to a specific genus or family:

• tobacco alkaloids;
• poppy alkaloids;
• ergot alkaloids, etc.

3. At the core biogenetic classification, proposed by the English scientist Hegnauer, lies the structure of amino acids, which are probable precursors of alkaloids in plants:

• tryptophan alkaloids;
• phenylalanine alkaloids, etc.

4. Most convenient and most often used in pharmacognosy chemical classification, proposed by A.P. Orekhov, which is based on the peculiarities of the chemical structure of alkaloids, in particular, the structure of a nitrogen-containing heterocycle.

Classification according to the structure of the carbon-nitrogen cycle

text_fields

text_fields

arrow_upward

Depending on the structure of the carbon-nitrogen cycle A.P. Orekhov divided all alkaloids into 13 groups:

1. Alkaloids with nitrogen in the side chain or acyclic alkaloids (without heterocycles): ephedrine from ephedra species, capsaicin from capsicum fruits, colchicine and colchamine from corms of crocus species.2. Alkaloids, derivatives of pyrrolidine and pyrrolizidine: platyphylline from ragwort.

3. Alkaloids, derivatives of pyridine and piperidine, are divided into several groups.

a) simple derivatives of pyridine and piperidine: lobeline from swollen lobelia, coniine from the fruits of hemlock spotted;

b) bicyclic non-condensed systems: anabasine from leafless anabasis, nicotine from tobacco leaves;

c) bicyclic condensed systems of piperidine and pyrrolidine (tropane derivatives): hyoscyamine, scopolamine from belladonna, henbane, datura species

4. Alkaloids, quinolizidine derivatives: pachycarpine, thermopsin, cytisine (Sophora thick-fruited, Thermopsis species).

5. Alkaloids, quinoline derivatives: quinine from cinchona bark, echinopsin from Echinops fruits.

6. Alkaloids, isoquinoline derivatives: morphine, codeine and papaverine from poppy pods, chelerythrine, sanguinarine from the herb celandine and macalea, glaucine from the herb maca yellow, berberine from barberry roots.

7. Alkaloids, indole derivatives: alkaloids of ergot, periwinkle, reserpine and ajmaline from the roots of rauwolfia, strychnine from chilibuha seeds, vinblastine and vincristine from the leaves of catharanthus rosea.

8. Alkaloids, purine derivatives: caffeine from tea leaves, coffee seeds, theobromine from chocolate tree seeds.

9. Alkaloids, quinazoline derivatives: peganine from the herb harmala vulgaris.

10. Alkaloids, imidazole derivatives: pilocarpine from leaves of pilocarpus species.

11. Steroid alkaloids: solasonine from the nightshade herb, hellebore alkaloids.

12. Diterpene alkaloids: alkaloids of aconites and larkspurs.

13. Alkaloids of unknown structure.

Based on this classification, raw materials containing alkaloids are also systematized.

To alkaloids belong to substances of plant origin contained in many plants. Currently, about 10,000 alkaloids are known.

Chemical properties of alkaloids

A common property of most alkaloids is the presence in their molecules of nitrogen contained in the cycles. Thus, alkaloids belong to heterocyclic compounds. Alkaloids are organic bases and form salts with acids. In most cases, alkaloids are contained in plants in the form of salts of malic, tartaric, citric and other acids. In the form of salts, they are soluble in water. Free alkaloids can be obtained by treating salts with alkalis. In their free form, alkaloids are usually insoluble in water, but soluble in organic solvents. A property common to all alkaloids is also that they are physiologically extremely active substances that have a strong effect on the animal organism; many of them are poisons.

The effect of alkaloids on the human body

Most alkaloids act on the nervous system: in small doses they have a stimulating effect, and in large doses they have a depressant effect. For example, cocaine, widely used in medicine as a local anesthetic, acts on the sensory endings of the peripheral nervous system. Curare, an alkaloid contained in the juice of some South American plants, acts on the motor endings of the nervous system and therefore causes paralysis; that is why it was used by the Indians to wet arrows. Morphine contained in the milky juice of the poppy acts on the central nervous system, inducing sleep; it is used in medicine as a general anesthetic. The nicotine contained in tobacco also affects the central and peripheral nervous system. Belladonna and Datura berries contain atropine, which has a strong effect on the motor nerves of the eye, dilating the pupil.

Structure of alkaloids

Alkaloids are very diverse in their structure. Depending on the chemical nature of the nitrogen heterocycle included in their composition, they are divided into the following main groups: 1) pyridine derivatives; 2) pyrrolidine derivatives; 3) derivatives of quinoline and isoquinoline; 4) indole derivatives; 5) purine derivatives, which include alkaloids - caffeine and theobromine; 6) alkaloids of terpenoid nature.

In some alkaloids we are dealing with a combination of various nitrogen heterocycles in the molecule. For example, in the nicotine molecule, pyridine and pyrrolidine are connected to each other. Usually, nicotine is included in the group of pyrididine alkaloids. Tobacco contains a number of alkaloids, the main ones being nicotine, ornicotine and anabasine.

Alkaloid nicotine

Nicotine upon oxidation, it forms nicotinic acid, which is an antipellagric vitamin; in the form of an amide, it is a component of some dehydrogenases. Free nicotine is a colorless, oily liquid. It is a highly toxic substance that affects the central and peripheral nervous systems. In case of nicotine poisoning, death occurs from respiratory paralysis. Nicotine is obtained in large quantities from waste from the tobacco industry and is used to combat insects that harm agriculture.

Nornicotine- an alkaloid obtained by removing the methyl group from nicotine. Anabasine was discovered by the largest Soviet researcher in the field of alkaloid chemistry, Academician A.P. Nut in the Central Asian plant Anabasis aphylla. Just like nicotine, anabasine is used to combat insects - agricultural pests. Research by A.A. Schmuck, a major authority in the field of tobacco chemistry, showed that individual botanical types of tobacco can vary greatly in the content of nicotine, nornicotine and anabasine. For example, regular cigarette tobacco (Nicotiana tabacum) and shag (Nicotiana rustica) contain nicotine. A number of species contain only traces of nicotine and predominantly nornicotine. Tobacco belonging to the species Nicotiana glauca contains only anabasine.

Alkaloid quinine

The most important representative of the group of alkaloids belonging to quinoline derivatives is quinine, found in the bark of the cinchona tree. It is used in medicine as a very effective medicine in the treatment of malaria.

Alkaloid morphine

Morphine- a representative of the group of isoquinoline alkaloids, found in opium - the condensed milky juice of the opium poppy. Opium contains a large number of different alkaloids and is widely used in medicine as a sedative, and in large doses as a narcotic. Morphine is widely used as a pain reliever.

Ergot alkaloids

The group of alkaloids - indole derivatives, includes a number of alkaloids contained in ergot horns. Ergot is a wintering form of the fungus Claviceps purpurea, developing in rye grain. Ergot is very poisonous, and if ground horns get into flour, it can lead to mass poisoning. Therefore, cleaning contaminated grain from ergot horns is the most important operation when processing such grain. Ergot horns are used in medicine. Currently, to obtain ergot alkaloids for their use in medicine, growing ergot on synthetic media is widely used. By changing the composition of the medium, the yield of alkaloids can be significantly increased. The structure of ergot alkaloids is based on lysergic acid or its isomer, isolysergic acid, which are indole derivatives synthesized in the ergot mycelium from tryptophan and mevalonic acid. By combining with one or more amino acids, pyruvic acid or amino alcohols, lysergic acid forms one or another ergot alkaloid. 12 alkaloids have been isolated from ergot horns: ergotamine and ergotaminine, ergosine and ergosinine, ergocristine and ergocristinine, ergocryptine and ergocryptinine, ergocornine and ergocorninine, ergobasine and ergobasinine. Ergot alkaloids are a good example of the fact that a given plant typically contains a complex of alkaloids; related in their chemical nature. We see the same picture in tobacco, opium poppy, and cinchona.