Pomegranate – Punica granatum L.



Homeland – Iran and Transcaucasia, where it occurs in the wild. It has long been cultivated as a fruit tree in tropical and subtropical countries, especially in the Mediterranean; culture was transferred to America.

A small tree with dark green leathery oblong-lanceolate leaves and beautiful bright red flowers; edible fruit – pomegranate.

The fruits are spherical, with the remains of a calyx at the top, yellow-red in color, with a thick, leathery, astringent peel. Inside the fetus there are 6-12 nests separated by membranous partitions; numerous seeds in the nests. Seeds are angular, surrounded by juicy, purple-colored pulp formed from the seed coat. Many varieties are known – with white pulp, there are seedless ones, with a pleasant smell (Sri Lanka).

For medical purposes, the bark (Cortex Granati) of the roots is collected, less often the trunks and branches. Root bark – flat and grooved pieces of different shapes and sizes; bark of trunks and branches in the form of tubular grooved pieces 10 cm long and 1-2 mm thick; the color outside is greyish or greenish-yellow. The inner surface is red-brown, smooth, traditionally with wood remains; fracture is even. There is no smell; the taste is strongly astringent. When wetting the inner plane of the bark with lime water, a yellow color appears; sections are stained black-blue (tannins) with a solution of iron-ammonium alum.


Pomegranate bark contains alkaloids, isopelletierine, methyl isopelletierine (together within 0.5%) and pseudopellettierine (up to 1.8%). The first two alkaloids are liquid, and pseudopelletterine is a crystalline substance. Liquid pelletierines are based on a piperidine ring linked to a propyl group oxidized to a ketone. Pseudopelletierine has a piperidine ring fused to a 4-membered ring that has an oxygen function.

Pomegranate bark and its products are used as a remedy for tapeworms. The specific antihelminthic effect is due to ieopelletierin and methylisopellettierin. Pseudopelletierin does not have this effect. Pelletierine refers to a product made from pomegranate bark, Pelletierinum tannicum.

The peel of the pomegranate fruit contains tannins (20-28%) and is successfully used in the treatment of dysentery and intestinal disorders.

The fruits of wild pomegranate give within 50% juice containing up to 10% citric acid. There are no other acids, so the juice is suitable for extracting citric acid.

The plant contains piperidine and pyridine alkaloids.



Alkaloids are called natural nitrogen-containing compounds of the main character, 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 proper.

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 Earth’s flora 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 found throughout the plant, or they can be 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, hypnotic poppy, 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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