Medicinal plants contain a number of substances that are extremely useful for disorders of physiological processes in the human body. Some of them are still unsurpassed in action by chemically synthesized substances.

Plants contain primary and secondary organic matter. The primary ones are carbohydrates, lipids and proteins, and the secondary ones are glycosides, saponins, alkaloids, tanning substances (tannins), essential oils, phytoncides, enzymes, plant hormones and others.

Some plants are much richer in secondary organic compounds than others. They are used with particular importance in herbal medicine.

Glycosides
Glycosides are found in all parts of plants. They are regulators in many biochemical processes. They have a burning and bitter taste, which probably protects the plants from herbivores. They are made of a sugar part - glycone and a non-sugar part - aglycone or genin. It is the contained aglycone that is responsible for the medicinal effect of the plants.

Depending on the chemical nature of the aglycone, glycosides are divided into several groups:

Cardiac - the name of this group of glycosides comes from their specific action on the heart muscle. The best-known plant representative containing glycosides is foxglove. In medicine, the herb is used for heart failure. Many of the plant species now known to contain cardiac glycosides were once used as lethal poisons. Therefore, the use of these plants should always be done under medical supervision.
Potions and infusions should not be prepared from plants containing glycosides (cornflower, lily of the valley, boyanka, humpback, yellow shiboi, goriksvet, zokum, and others), as they are difficult to dose! They are used only in the form of ready-made herbal preparations!

Coumarins - have a depressing effect on the central nervous system. Some of their derivatives have pain-relieving, diuretic and coronary vessel-dilating effects. Furanocoumarins are a group of coumarins that absorb ultraviolet light and are used in the treatment of vitiligo and baldness. Dicoumarol has an anti-coagulant effect (used in thrombosis), and esculin is similar to vitamin P.
A representative containing coumarins is yellow komuniga. It has been proven to have an anti-clotting effect.

Phenolic – over 100 different phenols have been proven in plant species. The leaves of gooseberry and cranberry contain arbutin and methylarbutin with a urinary tract disinfecting effect. White willow contains salicin. In folk medicine, willow barks are recommended for the treatment of malaria, colds, rheumatism.

Flavonoids - these are substances that are contained in almost all plants. Their name comes from "flavus" - yellow - they are pigments colored from pale yellow to yellow-orange. They are contained in almost all parts of plants - buds, leaves, roots, fruits and others. They are found in all higher plants, mosses and green algae.
In the human body, these substances increase the resistance of capillaries by increasing their elasticity; have a diuretic effect; stimulate heart activity, lower high blood pressure; have an antispasmodic effect; antibacterial; suppress the oxidation of adrenaline and ascorbic acid; affect the metabolism of iodine and calcium. Herbs containing flavonoids are used for hemorrhagic diathesis, chronic hepatitis, hypertension, hypovitaminosis P and C, skin diseases (eczema, dermatitis) and others.

Anthraquinones - a group of derivatives of anthraquinone and its derived anthrone and anthranol. Herbs containing them have a cleansing effect. They should not be used daily, as the body gets used to them (this may lead to the need to increase doses or intoxication). The effect of anthraquinones occurs about 10 hours after taking the herb (buckthorn bark and prickly buckthorn berries).

Anthocyanins - chemically similar to flavonoids. Their action resembles theirs - they affect the permeability of capillaries. They also have an anti-inflammatory effect and can be used for some eye diseases. They increase visual acuity in insufficient lighting (the fruits of the bilberry).

Iridoid - these compounds have a bitter taste. Some of them are antibiotics - they have antibacterial and antifungal effects; others have a sedative effect; third – appetizing. In addition, there are also iridoids with hypotensive and anti-inflammatory effects.

Cyanogenic - this type of glycosides release hydrogen cyanide when they break down, they are found in roots, seeds and leaves. They are widespread in the representatives of the Roztsvetni family, the Zhivenichevi family, the Elder family and others.

Thioglycosides – they contain sulfur. When decomposed under the action of ferments, essential oil is released - it strongly irritates the skin and mucous membranes. The richest representatives of thioglycosides are the Cruciferous family (black mustard, Latina, reseda, milkweed). Thioglycosides have antifungal and bacteriostats

Saponins are complex glycosides that are found together with resins, essential oils, fats and less often alkaloids. Their aqueous solutions, when shaken, form foam like soaps - hence their name. The aglycones of saponins are referred to as sapogenins.

They have the ability to hemolyze blood - the outer layer of red blood cells breaks when they come into contact with saponins. As a result, hemoglobin passes into the serum and the blood becomes transparent red. Because of this action, saponins are not administered intravenously. Taken orally, however, they are harmless.

Saponins are poisonous to animals with an unstable body temperature - reptiles, amphibians, fish.

They also have an irritating effect on the throat and nose, cause sneezing and discharge of secretions (have an expectorant effect). Some of them have a diuretic and blood pressure-lowering effect, in addition, they affect the metabolism and strengthen the body.

Compounds that contain nitrogen in their molecule. Alkaloids are products of the breakdown of protein substances in plants. Most of them are highly toxic and are used very carefully - only in therapeutic doses.

Alkaloids are essential for plant organisms. Confirmation of this is the fact that their concentration is different during different periods of development and increases when the plant is damaged (when the bark of the quinine tree is cut, the new bark has twice the amount of quinine).

Alkaloids do not accumulate uniformly in all parts of the plant, they are localized mainly in the roots and leaves. Their quantity also depends on: latitude, climatic conditions, altitude, soil, time of year, method of cultivation, time of picking and drying, and others.

Alkaloids act on the nervous system by stimulating or depressing it. Both effects can be achieved with the same means - the difference is in the administered dose.

More important groups of alkaloids:

Pyridine and piperidine - this refers to the nicotine contained in tobacco leaves; the highly poisonous coniine contained in hemlock; ricinin – in the castor plant (tick); lobeline – in lobelia and others.
Quinolizidine - cytisine contained in the leaves of the yellow acacia; sparteine – in various types of legumes.
Tropanes - atropine, L-hyoscyamine, scopolamine - are contained in licorice, tatul, blyan and others. Herbal products obtained from mad licorice have an antispasmodic and pain-relieving effect, they are used for stomach and intestinal colic, gallstones and kidney stones, spasms of the urinary tract and others.
Quinoline - the main alkaloid is quinine (obtained from the bark of the quinine tree). It is used as an appetite stimulant.
Isoquinoline - this group includes opium alkaloids - morphine, narcotine, papaverine, codeine, tabeine, narceine. They are contained in the hypnotic poppy, snake's milk, rosopasa, sorrel and others.
Indole - this includes the alkaloids of the carob. Products containing it are used in gynecology (for uterine bleeding or as a uterine tonic). This type of alkaloids is also found in wintergreen leaves, strychnosa seeds and others.
Purines - they include caffeine, theobromine, theophylline - they are contained in coffee, tea, cocoa.

Tannins (tannins)
Tannins are the main active ingredient of some medicinal plants such as gorse, oak, yarrow, sumac and others. Most often, they accumulate in the bark of tree species and the roots, rhizomes, leaves and stems of herbaceous plants.

They have the ability to increase the resistance of capillary walls; reduce their permeability; reduce the amount of cholesterol in the blood; enhance the resorption of vitamin C. In addition, in moderate doses, tannins on damaged skin or mucous membrane form a coagulation membrane that protects the underlying tissues and nerves from irritating agents. Extracts of plants containing tannins are used for diarrhoea.

Moderate doses of tannic substances are taken orally, so as not to cause damage to the mucous membrane (this can happen with the administration of gallotannin).

Larger doses can also be used for external application.

Tanning substances can also be taken for inflammation of the mucous membrane of the oral cavity, for eczema, dermatitis, hyperhidrosis, hemorrhoids, for small external hemorrhages, against sunburn and for frostbite of the skin.

Essential oils

It is believed that essential oils, on the one hand, attract insects needed for pollination, on the other hand, protect the plant from overheating (by evaporating), and also act as a protective agent for the plant against disease-causing bacteria, insects and rodents.

Essential oils are widely used as means to improve the taste and aroma of medicinal and food products. In addition, a large number of them are important in perfumery and cosmetics.

Substances possessing the properties of essential oils, with the difference that they are more or less volatile. They have the property of killing microorganisms. They are contained in almost all plants. For some of them, they have a protective function - they protect them from pests.

Phytoncides are contained in leeks, onions, garlic, horseradish, pine tops, yarrow, lemon.

Enzymes

Enzymes or enzymes are defined as protein substances that have the role of biological catalysts - they participate in almost all biochemical processes (by regulating both normal and pathological processes). It is characteristic of them that they do not undergo changes in the reactions in which they take part.

When the product formed as a result of these reactions reaches a certain concentration, the action of the enzymes stops. In this way, cells are protected from the harmful influence of metabolic products.

Plant hormones
They take part in the biosynthetic processes of the protoplasm. The lack of hormones inhibits the development of plants. Hormones are divided into:

bios - activating cell division and embryonic growth of plants;
auxins – stimulate cell growth
Phosphatides or lipids
These substances are found in the seeds of plants. They are necessary for the exchange of substances in the cells. Without them the protoplasm does not function properly. In medical practice, they are used as tonics.

Waxes
For plant species, these substances have a protective function. They settle on the surface of plant stems, leaves and fruits. They contain free fatty acids, alcohols and high carbohydrates. In medicine, they are used to prepare various ointments, pomades, plasters and others.