Foxglove looks like an ornamental plant. Sometimes it is even strange to see it in natural conditions – as if someone deliberately planted a garden plant in the forest or on the edge of the forest. It is equally effective both in the forest and on the homestead. People respect digitalis for its peculiar beauty and powerful medicinal effect.
Big-flowered foxglove is a herbaceous perennial up to 120 cm tall. The entire plant is covered with glandular pubescence. The lower leaves are short-petioled, light green, oblong-lanceolate, serrated from the edges or the entire edge, up to 25 cm long and up to 7 cm wide. The upper leaves are lanceolate, up to 4 cm long. Numerous bell-shaped, yellow-brown, drooping flowers are collected in a long one-sided tassel. The brown shade of the flowers depends on their veins (brown veins). Although, according to botanical terminology, foxglove flowers are bell-shaped, they most closely resemble foxgloves – hence the name of this wonderful plant. It blooms in June. The fruit is a densely pubescent capsule.
Foxglove usually grows on the edges of forests, among shrubs, in coniferous and broad-leaved and deciduous forests of the European territory of Russia and in Western Siberia. In Ukraine, it grows in Polissia, in the Carpathians and in the northern part of the forest-steppe zone. The native sister of the large-flowered foxglove, the purple foxglove (D. purpurea), is more often bred in homesteads due to its greater decorativeness and different shades of purple color of its flowers.
Due to its valuable medicinal properties, digitalis was introduced into culture. it is grown in special farms on plantations.
The leaves of the plant are used for the preparation of medicinal products, but without petioles. Usually, raw materials are collected twice a year: in the first year — at the end of summer, when the leaves reach an “industrial” length of 20 cm, and in autumn (no later than September). In plants of the second year of vegetation, leaves are harvested in the phase of shoot formation and during mass flowering. The collected leaves are immediately dried, first at a temperature of 55-60 °C for half an hour, and then dried at 40 °C. Raw materials are stored for up to two years, periodically checking suitability, and necessarily in a dry place, as its biological activity decreases when moistened.
Digitalis leaves contain cardiac glycosides, which during storage are converted into other compounds under the action of enzymes: digitoxin, gitoxin and steroid saponins – digitonin, digonin and gitonin. The leaves also contain flavonoids, choline, organic acids and other compounds.
The main active substances of the plant are cardiac glycosides. The most active of them are digitoxin and gitoxin. A feature of the action of the glycosides of these species of digitalis is the ability to increase the contraction of the heart muscle, while at the same time reducing their number. This improves the condition of heart patients and increases blood flow to such an important organ as the heart. The effect of glycosides also leads to an increase in the volume of blood that the heart ejects into the aorta, an increase in the speed of blood flow and a decrease in venous pressure. As a result of the normalization of blood circulation and the expansion of the blood vessels of the kidneys, the excretion of urine increases significantly. Therefore, digitalis products are useful for heart patients – they reduce and eliminate swelling caused by heart failure. Plant preparations are well absorbed and do not break down in the gastrointestinal tract. If normal use internally is not possible, they are administered by enema. Digitalis preparations begin to act after 2-4 hours, and the maximum effect occurs after 8-12 hours. They stay in the body for 18-21 days. Doctors call the plant the queen of heart remedies.
The main indications for the use of digitalis glycosides: heart failure of various origins and paroxysmal tachycardia. It is necessary to remember that the products accumulate in the body and have a toxic effect, so they are taken only with the consent of the doctor, strictly observing the dosage, and children are prescribed with special care.