Arnica

Arnica
Arnica montana Ill.Koehler
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Asterales
Family: Asteraceae
Subfamily: Asteroideae
Tribe: Heliantheae
Subtribe: Madiinae
Genus: Arnica
L.
Species

See text.

Arnica (Ár-ni-ca) is a genus with about 30 perennial, herbaceous species, belonging to the sunflower family (Asteraceae). The genus name Arnica may be derived from the Greek arna, "lamb", in reference to the soft, hairy leaves.

This circumboreal and montane (sub-alpine) genus occurs mostly in the temperate regions of western North America, while two are native to Eurasia (A. angustifolia and A. montana).

Arnica used to be included in the tribe Senecioneae, because it has a flower or pappus of fine bristles. This was soon questioned and Nordenstam (1977) placed it tentatively in tribe Heliantheae s.l. This arrangement also became uncertain because of the sesquiterpene lactone chemistry in certain species. Lately Arnica was placed in an unresolved clade together with Madiinae, Eupatorieae, Heliantheae s.s. and Pectidinae.

Several species, such as Arnica montana and Arnica chamissonis, contain helenalin, a sesquiterpene lactone that is a major ingredient in anti-inflammatory preparations (used mostly for bruises).

Arnica species are used as food plants by the larvae of some Lepidoptera species including Bucculatrix arnicella.

Arnica is also known by the names Mountain Tobacco and, somewhat confusingly, Leopard's bane and Wolfsbane - two names that it shares with the entirely separate species Aconitum.

Contents

Characteristics

They have a deep-rooted, erect stem, that is usually unbranched. Their downy, opposite leaves are borne towards the apex of the stem. The ovoid, leathery, basal leaves are arranged in a rosette.

They show large yellow or orange flowers, 6–8 cm wide with 10-15 long ray florets and numerous disc florets. The phyllaries (a bract under the flowerhead) has long spreading hairs Each phyllary is associated with a ray floret. Species of Arnica, with an involucre (a circle of bracts arranged surrounding the flower head) arranged in two rows, have only their outer phyllaries associated with ray florets. The flowers have a slight aromatic smell. If taken the wrong dose it can be very dangerous.

The seed-like fruit has a pappus of plumose, white or pale tan bristles. The entire plant has a strong and distinct pine-sage odor when the leaves of mature plants are rubbed or bruised.

Arnica montana

The species Arnica montana, native to Europe, has long been used medicinally, but this use has not been substantiated.[1][2]

Medicinal uses

Arnica montana has been used medicinally for centuries, however there are no scientific studies that prove the medical effectiveness.[1] The roots contain derivatives of thymol,[3] which are used as fungicides and preservatives. Arnica is currently used in liniment and ointment preparations used for strains, sprains, and bruises. Commercial arnica preparations are frequently used by professional athletes.[4]

The thymol derivatives concentrated in the plants roots have been clinically shown to be effective vasodilators of subcutaneous blood capillaries. A study of wound-healing after surgery to treat varicose veins found a trend towards a beneficial effect of reduction of pain and hematoma following surgery.[5]

Toxicity

Arnica contains the toxin helenalin, which can be poisonous if large amounts of the plant are eaten, and contact with the plant can also cause skin irritation.[6][7] If enough of the material is ingested, the toxin helenalin produces severe gastroenteritis, and internal bleeding of the digestive tract.[8] Homoeopathic preparations of Arnica 24X or more are not toxic as no or negligible amount of Arnica is left after dilution.[9][10][11]

Homoeopathy

Homoeopathic preparations of Arnica are widely marketed and used. In the UK, the Medicines and Healthcare products Regulatory Agency has registered the product for sprains and bruising under the National Rules for Homoeopathic Products (2006). These rules allow claims of efficacy for these conditions to be made on the packaging in the absence of similar evidence to that required for conventional medicines under the Medicines Act 1968 and 1971.[12] A systematic review of clinical trials showed that homeopathic arnica was no more effective than a placebo.[13] In some quarters, the fact that homeopathic Arnica has been the subject of published clinical trials at all has drawn criticism grounded on the allegation that the basic premise of the high dilutions used in homoeopathy would be inherently flawed.[11] With respect to the range of homoeopathic Arnica creams available on the market, these are generally formulated using the mother tincture rather than a dilution and therefore contain measurable quantities of the medicinally active substance.

Species

References

  1. ^ a b "Arnica in Flora of North America". Efloras.org. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=102636. Retrieved 2009-12-22. 
  2. ^ Clonal propagation of Arnica montana L., a medicinal plant Authors: Buthuc-Keul, A.; Deliu, C. Source: In Vitro Cellular and Development Biology - Plant, Volume 37, Number 5, September 2001 , pp. 581-585(5) Publisher: Springer
  3. ^ Weremczuk-Jezyna I, Kisiel W, Wysokińska H (2006). "Thymol derivatives from hairy roots of Arnica montana". Plant Cell Rep. 25 (9): 993–6. doi:10.1007/s00299-006-0157-y. PMID 16586074. 
  4. ^ Jenna Sumara (2006). "Arnica: the natural alternative for treating sore muscles". The Final Sprint. http://www.thefinalsprint.com/2006/12/arnica-the-natural-alternative-for-treating-sore-muscles/. Retrieved 2008-12-11. 
  5. ^ M. Wolfa, C. Tamaschkeb, W. Mayerc, M. Heger, "Wirksamkeit von Arnica bei Varizenoperation: Ergebnisse einer randomisierten, doppelblinden, Placebo-kontrollierten Pilot-Studie", Forschende Komplementärmedizin und Klassische Naturheilkunde, Vol. 10, pp. 242-247, 2003.
  6. ^ "Poisonous Plants: Arnica montana". Ces.ncsu.edu. http://www.ces.ncsu.edu/depts/hort/consumer/poison/Arnicmo.htm. Retrieved 2009-12-22. 
  7. ^ Edward Rudzki, Zdzisława Grzywa (1977) Dermatitis from Arnica montana Contact Dermatitis 3 (5), 281–281. doi:10.1111/j.1600-0536.1977.tb03682.x
  8. ^ Edible and Medicinal Plants of the West, Gregory L. Tilford, ISBN 0-87842-359-1
  9. ^ "Dynamization and Dilution". Creighton University Department of Pharmacology. http://altmed.creighton.edu/Homeopathy/philosophy/dilution.htm. Retrieved 2007-10-09. 
  10. ^ Vaughan, John Griffith; Patricia Ann Judd, David Bellamy (2003). The Oxford Book of Health Foods. Oxford University Press. p. 59. ISBN 0198504594. http://books.google.com/?id=mMl9vwVDxigC&pg=PA59&lpg=PA59&dq=%22arnica%22+homeopathic. 
  11. ^ a b Youngson, RM (1997-04). "Randomized trial of homeopathic arnica". Journal of the Royal Society of Medicine 90 (4): 239–240. PMC 1296246. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1296246. Retrieved 2011-06-02. 
  12. ^ "Arnica registered by medicines regulator ", Telegraph, 16 May 2009
  13. ^ "Trial shows that homoeopathic arnica is no better than placebo", Arch Surg, 1998.

Further sources

External links