arnica

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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 (English pronunciation: /ˈɑrnɨkə/) 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 (subalpine) genus occurs mostly in the temperate regions of western North America while two are native to Eurasia (A. angustifolia and A. montana).^{[citation needed]}

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.^{[citation needed]} 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.^{[citation needed]}

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 genus Aconitum.

Characteristics

A.chamissonis

Frigid Arnica near a training radar site in the Alaskan Interior.

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 seedlike 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] Homeopathic preparations of Arnica 24X dilution or more are not toxic as negligible amounts of Arnica remains.^[9][10][11]

Homeopathy

Homeopathic 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 homeopathy would be inherently flawed.^[11]

Species

• Arnica acaulis (Walt.) B.S.P. -- Common Leopardbane
• Arnica alpina (L.) Olin—Alpine Arnica (synonym of Arnica angustifolia subsp. alpina)
• Arnica amplexicaulis Nutt. -- Clasping Arnica, Streambank Arnica (synonym of Arnica lanceolata subsp. amplexicaulis)
• Arnica angustifolia Vahl—Narrowleaf Arnica
  • Arnica angustifolia subsp. alpina (L.) I. K. Ferguson
  • Arnica angustifolia subsp. tomentosa Downie & Denford
• Arnica cernua T.J. Howell—Serpentine Arnica
• Arnica chamissonis Less. -- Chamisso Arnica
  • Arnica chamissonis subsp. foliosa (Nutt.) Maguire
• Arnica cordifolia Hook. -- Heart-leaf Leopardbane, Heartleaf Arnica
• Arnica dealbata Baldwin (formerly Whitneya dealbata)
• Arnica discoidea Benth. -- Rayless Arnica
• Arnica × diversifolia Greene (pro sp.) -- Curtis Churchmouse Threeawn, Rayless Arnica, Sticky Arnica
• Arnica frigida C.A. Mey. ex Iljin—Snow Arnica (synonym of Arnica griscomii subsp. frigida)
• Arnica fulgens Pursh—Foothill Arnica, Orange Arnica, Shining Leopardbane
• Arnica × gracilis Rydb. -- Smallhead Arnica (a natural hybrid between A. latifolia and A. cordifolia)
• Arnica griscomii Fernald
  • Arnica griscomii subsp. frigida (C. A. Mey. ex Iljin) S. J. Wolf
  • Arnica griscomii subsp. griscomii
• Arnica lanceolata Nutt. -- Arnica, Lanceleaf Arnica
  • Arnica lanceolata subsp. amplexicaulis (Nutt.) Gruezo & Denford
  • Arnica lanceolata subsp. lanceolata Gruezo & Denford
• Arnica latifolia Bong. -- Broadleaf Arnica
• Arnica lessingii (Torr. & Gray) Greene—Nodding Arnica
  • Arnica lessingii subsp. lessengii
  • Arnica lessingii subsp. norbergii Hult. & Maguire
• Arnica lonchophylla Greene—Longleaf Arnica
  • Arnica lonchophylla subsp. arnoglossa (Greene) Maguire
  • Arnica lonchophylla subsp. lonchophylla
• Arnica longifolia D.C. Eat. -- Longleaf Arnica, Spearleaf Arnica
• Arnica louiseana Farr—Lake Louise Arnica
• Arnica mallotopus (formerly Mallotopus japonicus)
• Arnica mollis Hook. -- hairy arnica, wooly arnica
• Arnica montana L. -- Mountain Arnica
• Arnica nevadensis Gray—Nevada Arnica
• Arnica ovata Greene
• Arnica parryi Gray—Nodding Arnica, Parry's Arnica
• Arnica rydbergii Greene—Rydberg Arnica, Rydberg's Arnica, Subalpine Arnica
• Arnica sachalinensis (Regel) A. Gray
• Arnica sororia Greene—Twin Arnica
• Arnica spathulata Greene—Klamath Arnica
• Arnica unalaschcensis Less. -- Alaska Arnica
• Arnica venosa Hall—Shasta County Arnica
• Arnica viscosa Gray—Mt. Shasta Arnica

References

Further sources

• Maguire, B.; Gilly, C. L (1943). "A monograph of the genus Arnica (Senecioneae, Compositae)". Brittonia (New York Botanical Garden Press) 4 (3): 386–510. DOI:10.2307/2804900. JSTOR 2804900. 
• Wolf, S.J. & K.E. Denford (1984). "Taxonomy of Arnica (Compositae) subgenus Austromontana". Rhodora 86 (847): 239–309. 
• Nordenstam, B. 1977 Senecioneae and Liabeae—systematic review. In V. H. Heywood, J. B. Harborne, and B. L. Turner [eds.], The biology and chemistry of the Compositae, vol. II, 799–830. Academic Press, London, UK
• Baldwin, B. G. (1999). "New combinations in Californian Arnica and Monolopia". Novon (Missouri Botanical Garden Press) 9 (4): 460–461. DOI:10.2307/3392142. JSTOR 3392142. 
• Lyss, G., T. J. Schmidt, H. L. Pahl, and I. Merfort (1999). "Anti-inflammatory activity of Arnica tincture (DAB 1998) using the transcription factor NF-kappaB as molecular target". Pharmaceutical and Pharmacological Letters 9: 5–8. 
• Wolf, S. J., and K. E. Denford (1984). "Taxonomy of Arnica (Compositae) subgenus Austromontana". Rhodora 86: 239–309. 
• Stevinson, C., Devaraj, V. S., Fountain-Barber, A., Hawkins, S. and Ernst, E. (2003). "Homeopathic arnica for prevention of pain and bruising: randomized placebo-controlled trial in hand surgery". Journal of the Royal Society of Medicine 96(2): 60–65. 

External links

Look up arnica in Wiktionary, the free dictionary.

Wikisource has the text of the 1911 Encyclopædia Britannica article Arnica.

• American Botanical Council Web site Arnica information, news, and studies from The American Botanical Council
• Arnica in Plantarium Database - A Photo Guide.
• Arnica species
• UVSC Herbarium - Arnica
• Research Article Research indicating homeopathic arnica ineffective for muscle soreness due to lactic acid build-up following long distance running.
•  "Arnica". The American Cyclopædia. 1879. 

Gallery

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  Mountain Arnica (Arnica montana)

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  Longleaf Arnica (Arnica longifolia)