The herbal plant known as the foxglove can reach six feet in height. The foxglove has a straight stem without branches and grows as a biennial plant. During the spring bloom, foxglove flowers hang in bunches on the stem – the flowers have a dull pink or purple coloration, and often come with white spots on the corolla. The large sized leaves of the foxglove possess distinct and prominent veins running along the lamina.
Among all the traditional medicinal plants of old, the foxglove is considered to be among the loveliest, the most significant, the best known and even the most lethal. The plant poison called digitalis is simply the powdered down dried leaves of the foxglove plant. Digitalis is a well known cardiac stimulating compound that has helped millions of heart patients stay alive due to its property of stimulating the cardiac muscles.
The properties and beneficial effects of digitalis were discovered by an English physician William Withering, in 1775. In his research on herbal medications, he came to know of an old woman in Shropshire who was a practitioner of folk medicine mainly using wild herbs that she gathered in the countryside and the woods. This traditional healer cured a patient of the physician afflicted with excessive fluid retention as a complication of congestive heart failure. William Withering had in fact, expected the patient to die and was surprised by the curative powers of the remedy used by the old healer. Withering identified the foxglove as the curative herb from the old woman’s mostly useless bag of weeds. The physician found that foxglove was capable of treating the swelling or edema, which accompanies congestive heart failure in a person. Withering would also find the poisonous nature of the foxglove herb and the real ability of the digitalis in the herb to completely stop the pulsation of the human heart, even while it was also capable of shocking the heart into contraction. The physician would spend a decade conducting precise experiments on the use of the herb to determine the proper dosage for this new herbal remedy. Withering would publish a paper on the properties of the foxglove herb in 1785, the record of his findings is considered a classic of medical literature and was referred by many physicians in his day.
The shape of the blossoms give the herb its name, as the glove shaped flowers resembled gloved fingers and the name foxglove is an allusion to the white paws of the common red fox.
There are other common names for the foxglove plant and the medicinal plant is called by different names in different places. The name “dead man’s thimbles” is used to refer to the foxglove in Ireland; this name is a reference to the secretion of harmful juice from the plant. In England, the name “folks glove” for the foxglove, is an allusion to the traditional belief in fairy folk, who were said to inhabit woody areas where the foxglove is a common sight. Foxgloves have distinct spots on the flowers, these spots were traditionally said to mark the places where woodland elves had placed their fingers, as a warning of the plant’s poisonous nature. The name ‘Revbielde” or “fox bell” is given to the plant in Norway, this name springs from the Norwegian legend about bad fairies who supposedly gave this plant to a fox so as to enable the animal to quiet its footsteps while it was hunting among the chicken roosts in villages. The leaves of the foxglove were traditionally used by people living in North Wales to give the stone floors in their houses a mosaic look.
The foxglove was originally used by the Irish as a healing herb in the folk medicine of Ireland to treat skin problems such as boils and ulcers, as well as headaches and paralysis. The main chemical compound found in the foxglove plant is a glycoside called digitoxin; this chemical compound has been chemically isolated in the laboratory and is now artificially synthesized as well. The compound is employed as a major medication, called digitalis, used in the treatment of congestive heart failure and to right congenital heart defects in patients. The contraction of cardiac muscles is strengthened and boosted by the digitoxin; the compound also slows the pulsation rate of the human heart. Foxglove also contains one more important glycoside called digoxin; this compound has a diuretic effect on the kidneys and is used in some medications. The reason for the traditional fear of the foxglove herb is that any of the chemicals found in the plant are extremely dangerous when ingested in high doses by humans or animals. The compounds in the herb can induce cardiac rhythm disorders, sudden depression, heart failure or asphyxiation if they are ingested in large quantities.
A diseased human heart is profoundly benefited by the tonic effect of the foxglove remedy. The disruption of normal circulation in the body is the main reason for the worsening of heart disease in the human body. The rate of heartbeat and contraction is boosted and strengthened by the cardiac glycosides in the foxglove, as a result of this tonic effect, the heart beats slowly, regularly and without demanding more oxygen than the circulation can provide at any one time. The compounds present in the foxglove also stimulate the production of urine in the kidneys, this effect also leads to the lowering in the total volume of blood in circulation, and this brings a reduction in the load on the heart muscles.
While the foxglove has been mainly identified as a native English plant and associated with English countryside, it is found growing in many places throughout Europe and in the North American woods. The foxglove is a very easy to grow in most garden soils, particularly if such soils are rich in the content of organic matter and humus. The foxglove grows best in light dry soils in sites with a semi-shade; however, the plant can also succeed very well in sites with full exposure to the sunlight if the soil at the site is also moist or wet. The foxglove herb is also adapted to acidic soils and grows well in such soils. The plant also tolerates cold temperatures and is quite hardy, capable of tolerating temperate up to -25°c during the winter months. Temperate woodlands are easily colonized by the foxglove especially if such sites are shaded to some extent. The foxglove is an ornamental plant and a favorite of many gardeners around the world. The main reason for the commercial cultivation of the foxglove is for the useful glycosides it contains, these chemical compounds form the basis for the important heart medicine called digitalis. Herbalists also commonly use this species in the preparation of herbal heart remedies, the sub-species called D. lanata on the other hand is commercially grown for supplying the pharmaceutical industry with natural digitoxin. Foxglove plants grown at sites with good daily exposure to incumbent sunlight typically contain greater concentrations of the beneficial and medically active compounds – therefore, site selection is important when commercially cultivating foxglove plants. Apiarists also favor the foxglove as bees are attracted to its flowers due to their high nectar content. Each individual foxglove plant can give to two million seeds in its lifetime. Browsing animals such as deer and rabbits almost never trouble the members of this plant genus – due to the fact that most of them are poisonous. The foxglove grows well in mixed woods and is a good companion plant for other trees and shrubs growing on a site. The foxglove stimulates the growth of neighboring plants and trees, especially growing well among pine trees in temperate woodlands.
The foxglove herb is normally propagated using stored seeds. The seeds are surface sown early in the spring in a cold frame inside a greenhouse. Foxglove seeds typically take two to four weeks at 20°C to germinate. Once the seedlings emerge and plants begin to grow and become large enough to handle by hand, each individual seedling is pricked out into its own pot and these pots are then planted out in the permanent sites for the plants when summer arrives the following year. When the supply of seeds is sufficient, they can be sown out of doors at the permanent site during the spring or the fall – this practice is advisable only if seed stocks are abundant as the mortality rate of such seedlings planted directly out of doors tends to be rather high compared to seedlings grown indoors.
Foxglove contains cardiac glycosides (including digoxin; digitoxin, and lanatosides), anthraquinones, flavonoids, and saponins. Digitoxin rapidly strengthens the heartbeat but is excreted very slowly. Digoxin is preferred as a long-term medication.