Yew is a green coniferous tree that can also be used as a medicinal plant. However, most of its components are very poisonous.
Occurrence and cultivation of yew
Although the tree is called European yew, its distribution area also extends beyond the European continent. The yew (Taxus baccata) also bears the names European yew or common yew. The tree belongs to the yew family (Taxaceae) and belongs to the order of conifers (Coniferales). The European yew is an evergreen conifer and reaches heights between 2 and 15 meters. Depending on the local conditions, the yew can also grow as a shrub. Thus, in the high mountains or on rock faces, it even occurs as a creeping shrub. The trunk has a reddish-brown bark. The leaves of the tree are evergreen needles. The flowering of the yew occurs in April and May. From August, one or two seeds emerge from the flowers, which have a green-brown coloration. They are contained in a red fruiting body, which has a fleshy covering. The seeds are dispersed by birds. Although the tree is called European yew, its range extends beyond the European continent. Thus, its habitat extends from Europe through the Atlas Mountains of northwest Africa, Asia Minor, and the Caucasus region to northern Iran. In Europe, the yew prefers to thrive in shady forests. It is also found as an ornamental shrub in parks or cemeteries. It prefers soils rich in lime and nutrients.
Effect and application
The constituents of European yew include biflavonoids, phenols, vitamin C, taxacins, taxin A and taxin B. Other constituents include betuloside, diterpenes, baccatin III, paclitaxel, and ginkgetin. Apart from the seed coat of yew, all other parts of the tree are considered poisonous. Even drying or cooking cannot eliminate the toxic substances. The toxicity of tree parts such as seeds, needles, bark, and wood varies from tree to tree. It also depends on the season. On the other hand, the red seed coat of the ripe fruits is non-toxic. These have a sweet taste and can be eaten raw. However, the poisonous seeds must not be swallowed under any circumstances, as they are toxic. The fruits are considered helpful against scurvy. Children should refrain from eating the fruits as there is a risk of swallowing the seeds. For medicinal use, the fresh branch tips of yew are primarily used. The medicinal active substances include cyanogenic glycosides such as biflavonoids, taxiphylline, ginkgetine, sciadopitysine, baccatin III, as well as diterpene alkaloids of the taxane type. For external use, a tincture made from the needles of the tree is used. It is used for the therapy of skin parasites. Since the active substances of the common yew are suitable for the treatment of cancer, they are also used internally, despite their toxicity. However, self-treatment is not possible, so the use of the medicinal plant must always be under the supervision of a doctor. In the Middle Ages, yew also functioned as a therapeutic incense. Thus, inhaling the smoke was supposed to relieve cold symptoms such as coughs and colds or lung diseases. Due to its toxicity, conventional medicine has largely dispensed with the European yew in modern times. However, it has therapeutic value for homeopathy. The latter produces the homeopathic remedy Taxus baccata from the yew twigs. For this purpose, the remedy is diluted to such an extent that it cannot cause any harm. Among other things, it is used to treat gastrointestinal complaints and skin diseases.
Importance for health, treatment and prevention.
In ancient times, yew was first used as a means to poison people. Thus, the tree’s poison was considered fast-acting and effective. The Celts used yew sap for their arrow poisons. In addition, yew was said to have magical effects and to be able to summon or drive away spirits. In addition, it came to the production of magic wands from yew wood. Numerous cultures classified the yew tree as sacred. In the Middle Ages, yew was also used as a medicinal plant. One of the first therapeutic users was the Persian physician Avicenna in 1021, who first used the plant to treat rabies, snakebites, gallbladder complaints and liver ailments.In folk medicine, the European yew was then used to treat heart complaints, epilepsy, rheumatism, diphtheria, scabies or worm infestation. It was administered to women to promote menstruation. A decoction of yew needles also served as an effective abortifacient. However, the toxicity of yew posed a risk to patients that should not be underestimated. Since numerous non-toxic alternatives are now available, herbal medicine in the present day has dispensed with the use of the toxic plant. Since the 1990s, yew has once again been of interest to orthodox medicine because of the successful semi-synthetic isolation of the cell division-inhibiting substance paclitaxel. This substance could previously only be isolated from the bark of the Pacific yew (Taxus brevifolia). The isolation was carried out from the taxane compounds within the yew needles. Thus, substances from the yew are used today against cancers such as ovarian cancer, bronchial cancer and breast cancer. However, since there is a risk of severe side effects, the application takes place only in case of failure of all other forms of treatment. Homeopathy applies substances of yew primarily for the treatment of skin rashes and digestive disorders. Other indications include heart disease, gout, rheumatism, and liver disease.
