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Useful properties of tannins.

The usual tart taste of various plant fruits, nuts, seeds, teas and infusions from leaves, flowers and seeds, as well as the tart-bitter taste of some herbal pharmaceuticals that are habitually used in nutrition and treatment, are provided by tannins or tannins (Hallotannic acid). Gallodubic acid is soluble in water and alcohols. In solutions, upon contact with protein structures, it precipitates (with the formation of protein and gelatinous precipitates). In contact with a number of metals and metal salts, for example, with copper, tin, zinc and iron, it stains the plant parenchyma in dark colors, which makes it unacceptable to store and cook dishes from raw plants (juices, salads, soups) in dishes from the mentioned types of metal. It is due to the property of tannins to oxidize in the presence of oxygen that one can see how the fruit pulp darkens from contact (pressing, hitting, breaking or completely removing the skin). Such properties of tannins in plants spoil the appearance of fruits when they are damaged, but to prevent discoloration during canning or other types of fruit harvesting, they are fumigated with SO₂ or hermetically sealed, stopping the access of air.

Tannins are substances of exclusively vegetable origin. For plants, tannins perform important functions that regulate dormancy and increase resistance to phytopathogenic microorganisms. But for human health, tannins also perform a number of useful functions, which led to the widespread use of the properties of tannins in medicine and pharmaceuticals.

The beneficial properties of tannins have been known since the time when mankind learned how to trim animal skins. This made it possible to prevent the processes of rotting skins. Tannins entered medicine due to their ability to denature proteins and in particular collagen. Such properties made it possible to attribute tannins to a number of antiseptic substances of plant origin, which are still used to this day when it is necessary to treat wound surfaces of the skin and mucous membranes. The antiseptic and anti-inflammatory effect of tannins is ensured by their ability to coagulate mucus or exudate proteins in the wound, which leads to thickening of cell membranes and the formation of a film that protects the nerve endings in the tissues of the mucosa and skin, and also leads to capillary constriction. This effect has a protective, analgesic and anti-inflammatory effect on the tissues of the skin and mucous membranes. Any scratch, cut or abrasion, as well as manifestations of a skin disease associated with cracking of the skin or mucous membranes, can be treated with rinses, compresses and baths with the participation of tannins, which will have a healing, antiseptic, antipruritic and mild analgesic effect.

The impact on the nerve endings in the tissues of the organs with the help of tannins plays another important role in the health of the human body - it reduces the peristalsis of the intestinal walls and thereby stops the attacks of diarrhea. Tannin-based pharmaceutical preparations and home-made infusions from plants with a high content of tannins can treat intestinal disorders associated with increased intestinal motility. But tannins are categorically not used to treat infectious diarrhea caused by the presence of harmful bacteria, viruses, fungi or protozoa in the human body, despite their antiseptic effect, since the ability to effectively use antimicrobials is impaired - the degree of their impact on microorganisms is reduced.

Where are tannins found in plants?

The first tannins were obtained from the bark, fruits and young shoots of oak. On an industrial scale, tannins are obtained from vegetable raw materials of Asia Minor oak, from the fruits of the plant Gallae Nurcicae (Ink nuts), plants of the Sumac family, including Sumac (Rhus coriaria L.). These plants contain the highest concentrations of tannins.

In sufficiently large quantities, tannins are found in the leaves and stems of the tea tree, in fruits - in apples, pears, cherries, plums, currant (black and red), peaches and apricots, figs, berries strawberries, raspberries, lingonberries, blueberries, blackberries, bird cherry, mountain ash, in pistachio and almond nuts, in walnuts, in seeds of spicy plants. All these plants are useful as prophylactic agents to improve bowel function, to treat the oral mucosa and intestines.

One of the interesting properties of tannins, which can be converted into other substances under certain influences (for example, high-temperature and enzymatic influences), allows the use of infusions from certain types of fruits, grains, leaves or plant roots as invigorating drinks. Gallodubic acid can be converted to a number of other acids, including caffeic acid, which accounts for the property of many plants containing high concentrations of tannin to mimic the effects of coffee.

In general, tannins have many useful purposes in everyday life, in culinary business, in the treatment and prevention of diseases, which makes them very important components of nutrition and maintaining human health.