Arnica montana
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Arnica montana, also known as , leopard's bane, mountain tobacco and mountain arnica,<ref name="FAO">Template:Cite web</ref> is a moderately toxic European flowering plant in the daisy family Asteraceae that has a large yellow flower head. The names "wolf's bane" and "leopard's bane" are also used for another plant, Aconitum, which is extremely poisonous.
Arnica montana has been used as a herbal medicine, but there is insufficient clinical evidence for its therapeutic use, and it is toxic when taken internally or applied to injured skin.<ref name="drugs">Template:Cite web</ref>
Description
Arnica montana is a flowering plant about Template:Convert tall aromatic fragrant, herbaceous perennial. Its basal green ovate leaves with rounded tips are bright coloured and level to the ground. In addition, they are somewhat downy on their upper surface, veined and aggregated in rosettes. By contrast, the upper leaves are opposed, spear-shaped and smaller which is an exception within the Asteraceae. The chromosome number is 2n=38.
The flowering season is between May and August (Central Europe). The Template:Cvt flower heads are composed of orange-yellow disc florets in the centre which are externally bordered by 10 to 15 yellow ray florets. The achenes have a one-piece rough pappus which opens in dry conditions.<ref>Arnica montana L., relevant European medical plant (2014). Waizel-Bucay J., Cruz-Juarez M. de L. Revista Mexicana de Ciencias Forestales, Vol. 5 Issue 25 pp. 98–109</ref><ref>Template:Cite web</ref> Arnica montana is a hemicryptophyte,<ref>Template:Cite web</ref> which helps the plant to survive the extreme overwintering condition of its habitat. In addition, Arnica forms rhizomes, which grow in a two-year cycle: the rosette part grows at its front while its tail is slowly dying.<ref name=":0" />
Taxonomy
The Latin specific epithet montana refers to mountains or coming from mountains.<ref>Archibald William Smith Template:Google books</ref>
Distribution and habitat
Arnica montana is widespread across most of Europe.<ref>Template:Cite web</ref> It is absent from the Celtic Isles and the Italian and Balkan peninsulas.<ref name="euromed.luomus.fi">Template:Cite web</ref> In addition, it is considered extinct in Hungary and Lithuania.<ref name="euromed.luomus.fi"/> Arnica montana grows in nutrient-poor siliceous meadows or clay soils.<ref name=":0" /> It mostly grows on alpine meadows and up to nearly Template:Convert. In more upland regions, it may also be found on nutrient-poor moors and heaths. However Arnica does not grow on lime soil,<ref name=":0" /> thus it is an extremely reliable bioindicator for nutrient poor and acidic soils. It is rare overall, but may be locally abundant. It is becoming rarer, particularly in the north of its distribution, largely due to increasingly intensive agriculture and commercial wildcrafting (foraging).<ref>Template:Cite book</ref> Nevertheless, it is cultivated on a large scale in Estonia.<ref name="euromed.luomus.fi"/>
Chemical constituents
The main constituents of Arnica montana are essential oils, fatty acids, thymol, pseudoguaianolide sesquiterpene lactones and flavanone glycosides.<ref name="foods">Template:Cite journal</ref> Pseudoguaianolide sesquiterpenes constitute 0.2–0.8% of the flower head of Arnica montana. They are the toxin helenalin and their fatty esters.<ref>Template:Cite book</ref> 2,5-Dimethoxy-p-cymene and thymol methyl ether are the primary components of essential oils from both the plant's roots and rhizomes.<ref>Template:Cite journal</ref> The quality and chemical constitution of the plant substance Arnicae flos can be monitored by near-infrared spectroscopy.<ref name="foods" />
Cultivation
Arnica montana is propagated from seed. Generally, 20% of seeds do not germinate. For large scale planting, it is recommended to raise plants first in a nursery and then to transplant them in the field. Seeds sprout in 14–20 days but germination rate depends highly on the seed quality. Planting density for Arnica montana is of 20 plants/m2 such that the maximum yield density will be achieved in the second flowering season. While Arnica montana has high exigencies of soil quality, analyses should be done before any fertilizer input.<ref>B.M.Smallfield & M.H. Douglas (2008) Arnica montana a grower‟s guide for commercial production in New Zealand. New Zealand Institute for Crop and Food Research Limited</ref>
The flowers are harvested when fully developed and dried without their bract nor receptacles. The roots can be harvested in autumn and dried as well after being carefully washed.<ref name=":0">Template:Cite book</ref>
Arnica montana is sometimes grown in herb gardens.<ref name="efloras"/>
Use in herbal medicine
Arnica montana has been used as a herbal medicine.<ref name="efloras">Template:Cite web</ref> When used as a topical medication in a gel at 50% concentration, A. montana was found to have the same effectiveness (albeit with possibly worse side effects) as a 5% ibuprofen gel for treating the symptoms of hand osteoarthritis.<ref>Template:Cite journal</ref> A 2014 review found that A. montana was ineffective at concentrations of 10% or less for pain, swelling, and bruises.<ref>Template:Cite journal</ref> A 1998 review of homeopathic A. montana (all such preparations are so dilute that they contain none of the plant) found it is no more effective than a placebo.<ref>Template:Cite journal</ref>
Toxicity
The US Food and Drug Administration has classified Arnica montana as an unsafe herb because of its toxicity.<ref name=drugs/> It should not be taken orally or applied to broken skin where absorption can occur.<ref name=drugs/> Arnica irritates mucous membranes and may elicit stomach pain, diarrhea, and vomiting.<ref name=drugs/> It may produce contact dermatitis when applied to skin.<ref name=drugs/>
Arnica montana contains the toxin helenalin, which can be poisonous if large amounts of the plant are eaten or small amounts of concentrated Arnica are used. Consumption of A. montana can produce severe gastroenteritis, internal bleeding of the digestive tract, raised liver enzymes (which can indicate inflammation of the liver), nervousness, accelerated heart rate, muscular weakness, and death if enough is ingested.<ref>Template:Cite book</ref><ref name=pmid11558636>Template:Cite journal</ref> Contact with the plant can also cause skin irritation.<ref>Template:Cite web</ref><ref>Template:Cite journal</ref> In the Ames test, an extract of A. montana was found to be mutagenic.<ref name=pmid11558636/>
Market
The demand for A. montana is 50 tonnes per year in Europe, but the supply does not cover the demand.Template:Citation needed The plant is rare; it is protected in Belgium, France, Germany, Italy, Poland, and in some regions of Switzerland.Template:Citation needed France and Romania produce A. montana for the international market.<ref>Pasquier, B., Godin, M. (2014) L'arnica des montagnes, entre culture et cueillette. Dossier simple et aromatique, Jardins de France 630.</ref> Changes in agriculture in Europe during the last decades have led to a decline in the occurrence of A. montana. Extensive agriculture has been replaced by intensive management.<ref>Michler, B. (2007) Conservation of Eastern European Medicinal Plants Arnica Montana in Romania</ref>
References
External links
- Article concerning testing involving Arnica at the Royal Society of Medicine (archived)