Sabadilla

Veratrnm sabadilla Brandt

 

 

It grows in alpine meadows in the mountains of Central America and in the northern part of South America.

Monocotyledonous perennial bulbous plant. The bulb develops 5-6 long linear leaves and one flower arrow reaching 1 m in height. Inflorescence spike-shaped; flowers inconspicuous, greenish. The fruit is a three-cell drop-down box; each nest contains 2-3 seeds.

Seeds (Semen Sabadillae) are oblong-lanceolate in shape, dark brown in color, 5-9 mm long and up to 2 mm in diameter, somewhat curved, pointed at the apex, thickened and rounded at the base, where a scar is visible. The surface of the seed is covered with longitudinal wrinkles. There is no smell; the taste is burning and bitter; poisonous, causes powerful salivation. The powder strongly irritates the respiratory tract and mucous membranes of the eyes and nose.

The seeds contain A-5% steroidal alkaloids, the sum of which is known as veratrin. The main one in the amount is cevadin, which is an esterified derivative of cevanin in the form of a glycoside. The name Veratrinum was given to alkaloids in the 19th century, when botanists, knowing little about the plant, assigned it to the genus Veratrum. Later, when the plant was renamed, the chemical name of the alkaloids remained traditional.

Seed decoction (Decoctum Sabadillae) and tincture (Tinctura Sabadillae) are used as an antiparasitic agent. Veratrin is used in ointments as an irritant and distraction for rheumatism and neuritis. Ingested seeds cause severe diarrhea and vomiting, in a toxic dose – a general breakdown and death.

Sabadilla seeds began to arrive in European pharmacies in the 17th century. The amorphous base, called veratrin, was first isolated in 1818 by Pelletier and Cavent. In 1885, Merck isolated the crystalline alkaloid cevadin from this amorphous substance.

The plant contains steroidal alkaloids (glycoalkaloids).

 

PLANTS CONTAINING STEROID ALKALOIDS (GLYCOALKALOIDS)

Steroid alkaloids are called glycosides, in which aglycones are nitrogen-containing steroid compounds with 27 carbon atoms, which are derivatives of cyclopentanperhydrophenanthrene. In structure, they are analogues of steroidal saponins and differ from them in the content of a nitrogen atom in the fifth or sixth (E, B) ring in aglycone (sapogenin). Steroidal alkaloids, like steroidal saponins, have surface-active and hemolytic properties and form molecular compounds with cholesterol and related sterols.

Steroid alkaloids can be of several types, including:

 

 

 

PLANTS CONTAINING ALKALOIDS

Alkaloids are called natural nitrogen-containing compounds of the main nature, formed in plants. Groups of proteinogenic amines (for example, tyramine) and betaines (stakhidrin, trigonelline, etc.) adjoin the alkaloids, which are considered as transitional compounds from the simplest nitrogen-containing compounds (methylamine, trimethylamines, etc.) to the alkaloids themselves.

Of natural pharmacologically active substances, alkaloids are the main group from which modern medicine draws the largest number of highly effective drugs.

According to world literature, by the end of the past decade, the number of alkaloids isolated from the higher plants of the flora of the Earth exceeded 5000. According to modern concepts, alkaloid-bearing plants make up 10% of the entire world flora. The families Equisetaceae, Lycopodiaceae, Ephedraceae, Liliaceae, Amaryllidaceae, Dioscoreaceae, Chenopodiaceae, Nymphaeaceae, Ranunculaceae, Berberidaceae, Menispermaceae, Papaveraceae, Fabaceae, Rutaceae, Cactaceae, Punicaceae contain the largest number of alkaloid-bearing genera and species. Loganiaceae, Apocynaceae, Borraginaceae, Solanaceae, Rubiaceae.

Usually plants that are phylogenetically close contain alkaloids that are very similar in structure, thus forming a natural group of genera. For example, plants of the genera Atropa, Datura, Hyoscyamys, Scopolia, Physochlaina, Duboisia. Mandragora (all from the same Solananeae family) contain a well-defined group of tropane alkaloids. This far-reaching pattern, however, has exceptions that have not yet been explained. So, for example, caffeine is found in plants that are not systematically related to each other: tea (Theaceae), coffee (Rubiaceae), cocoa (Sterculiaceae), mate (Aquifoliaceae), guarana (Sapindaceae), erodium (Geraniaceae). Along with this, there are cases when their 2 very close systematically species, one is rich in alkaloids, and the other either does not contain them at all, or contains alkaloids of a different structure.

Alkaloids can be contained throughout the plant or formed and accumulated only in one or more specific organs. The plant traditionally contains not one, but several alkaloids. In individual plants, there may be 20 or more of them (cinchona, sleeping pills, etc.), and they may be similar in structure or belong to different chemical groups. In the sum of alkaloids, 1–3 traditionally predominate quantitatively (the main alkaloids). In plants, alkaloids are dissolved in the cell sap of the main parenchyma, phloem, and other tissues in the form of salts, mainly organic acids (malic, succinic, citric, oxalic, fumaric, quinic, etc.); of mineral acids, phosphoric acid is more often involved.

The quantitative content of alkaloids is, in principle, a species characteristic, and it varies over a very wide range. For example, in black henbane they are only 0.05-0.1%, and up to 15% accumulate in the cinchona bark. In the process of ontogenetic development of plants, their alkaloid content undergoes quantitative and sometimes qualitative changes, and each species has its own regularities.

The content of alkaloids in plants is influenced by their geographical location and various factors (air and soil temperature, precipitation, duration and intensity of sunlight, shading, height above sea level, etc.), as well as human impact in the case of transferring the plant to cultivation or its acclimatization. The largest number of alkaloid-bearing species, moreover, with a high content of alkaloids, is common in subtropical and tropical states with a humid climate. Alkaloids of different structure are confined to certain latitudes, and in connection with this, their pharmacological activity changes.

There is no consensus on the biological role and causes of the formation of alkaloids in plants. The main hypotheses proposed at different times interpret alkaloids as: 1) waste products of the vital activity of a plant organism; 2) spare substances; 3) protective substances; 4) active substances necessary for biosynthesis. The latter hypothesis is currently considered by most scientists to be the most general one, which, however, does not exclude other biological functions of alkaloids.

The exceptional diversity in the structure of alkaloid molecules does not allow us to imagine a single way of their formation in plants. Their biosynthesis proceeds according to specific schemes with the most complex chemical transformations (ring opening and closing, oxidation, deamination, ring condensation, etc.) through many intermediate products. Some alkaloids begin biogenesis from amino acids, others from acetic acid (in other words, from carbohydrates).

The modern classification of alkaloids is based on the nature of the heterocycles included in their molecules, with the release into a separate group of alkaloids with an aliphatic structure and with nitrogen in the side chain.

1. Alkaloids with an aliphatic structure or with nitrogen in the side chain;

2. Pyrrolizidine alkaloids.

3. Piperidine and pyridine alkaloids.

4. Alkaloids with condensed and pyrrolidone and piperidine rings.

5. Quinoline alkaloids.

6. Quinazoline alkaloids.

7. Isoquinoline alkaloids.

8. Indole alkaloids.

9. Alkaloid of the imidazole group.

10. Purine alkaloids.

11. Diterpene alkaloids.

12. Steroid alkaloids (glycoalkaloids).

13. Alkaloids of unknown structure.

In conclusion of this brief review, it should be pointed out that most alkaloids are highly active substances with selective pharmacological action. The selectivity of the action of alkaloids determines their widespread use for medicinal purposes. The main forms are extraction products (tinctures, extracts, novogalenic preparations, etc.) and pure alkaloids isolated from plants, converted into soluble salts of certain inorganic and organic acids.

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