The most common in Latvia are red foxglove (Digitalis purpurea L.), which is usually a luxuriant plant and sown wild from gardens, and large-flowered foxglove (Digitalis grandiflora Mill.), which already lives freely in Latvia, but is more common in the eastern part of Latvia, the plant is protected and after its properties may also make it not particularly desirable to harvest.
Red Foxglove is a biennial or perennial plant, 40-150 cm tall, rarely 200 cm. In the first year of life, the red thimble forms a rosette of leaves, with elongated, oval or elongated oval leaves, width 15 cm, length 30 cm. In the second year of life, one or more erect, unbranched stems form. The lowest leaves are on long stems, oval, 15-20 cm long, the middle leaves are on short stems, the highest leaves are sessile. The leaves are dark green, strongly hairy, the veining is pronounced. The flowers are large, located at the top of the stem, arranged in a one-sided spike (flowers facing one direction). The flower is light or dark pink, rarely white, spotted inside. Fruit - a two-seeded box. Blooms in June-July, in rare cases flowering continues until September.
The big-flowered foxglove is a perennial plant with a short root. The stem is erect, 50-120 cm tall. The leaves are light green, the lowest - on short stems, elongated lanceolate, up to 25 cm in length; upper length up to 4cm, sessile. Stem and leaves hairy. The flowers are located at the top of the stem, in a one-sided spike inflorescence. The flower is yellow with brown veins. Fruit - an egg-shaped box, heavily hairy with many seeds. The plant blooms in the first half of summer.
Foxglove leaves are used for medicinal purposes. In the first year of the plant's life, rosette leaves are collected, which often manage to be collected up to 3 times during the summer. In the second year of the plant's life, the leaves of the stem are collected immediately after the plant flowers. Late collection of leaves loses its medicinal value. The leaves are collected in sunny and dry weather. The leaves are dried spread out in the sun or in forced dryers not exceeding 50-60C. When drying, the drug needs to be stirred often. The drug is valid for 2 years.
The surface part of the plant contains cardiac glycosides (digitoxin, beta-acetyldigitoxin, digitonin, gitoxin, gitonin, tigonin), purpureaglycoside A and B, which turn into primary (secondary) glycosides during drying and storage. Foxglove berries also contain organic acids, saponins, flavonoids (luteolin-7-glucoside, digitolutein), choline and other compounds.
Foxglove preparations have a broad spectrum of effects on the body: on blood vessels, nerves, kidneys, intestines, CNS, but the main object of action is the heart.
The heart-affecting glycosides contained in foxgloves have a high level of resistance when compared to those found in other plants. The plant acts on the heart within 2-4 hours, so it can be included as a slow-acting cardiac glycoside-containing agent, but its effect lasts for 2-3 weeks, which makes this plant unique compared to other plants with a similar effect.
When these glycosides are taken orally, they accumulate slowly and have high cumulation. Digitoxin is eliminated from the body in an average of 160 hours.
Digitoxin and gitoxin act primarily on the heart. These glycosides accumulate in heart tissue. The heart is very sensitive to these glycosides. Glycosides have a depressing effect on the heart, preventing it from accelerating.
Under the influence of cardiac glycosides, total-peripheral vascular resistance decreases, tissue blood supply and oxygenation process improves. When using Foxglove preparations, heart function is normalized, heart size decreases, venous blood pressure decreases and diuresis increases. Edema, shortness of breath and cyanosis disappear in patients, liver function normalizes, overall hemodynamics improves, plant blood supply and oxygen supply are restored, the pulse becomes less frequent.
Both types of Foxglove are widely used in folk medicine. Initially, they were used as diuretics to reduce edema. They were also used to treat circulatory disorders, hypertension, cardiovascular disease, liver disease, inflammation of the pancreas, spleen, stomach, depression, insomnia, and migraine. Foxglove decoction compresses were used as a wound healing agent.