by Olivia Questore
Arnica spp. are rhizomatous herbaceous perennial herbs that
belong to the Asteraceae (aster family) (Sugier, et al. 2013). Their
common names include Wolf’s-bane, Leopard’s Bane, European Arnica,
Mountain Tobacco, Wolfsbane, and Mountain Snuff (WebMD n.d.). Arnica
is native to both North America and Europe (Sugeier 2013). Some
species of Arnica are endangered within their native region
in Europe (Sugeier 2013). Within North America, Arnica is
predominantly found in the North West projecting upward into Canada
and South into the northern regions of New Mexico, Arizona, Nevada,
Colorado, and California (Gruezo & Denford 1995). Thirty species
within the genus are found in North America (USDA 2015). Primarily,
Arnica’s endangerment status is due to habitat loss, but the
high demand and collection for medicinal uses creates additional
stress on the species (Falniowski, et al. 2013). Arnica
is found primarily in shrubland and alpine mountain environments
(Falniowski, et al. 2013). Additionally, the herb can be found in
pine forests, meadows, open forest edges, mowed pastures, and
road/path sides (Falniowski, et al. 2013). The genus
contains many medicinally viable species, although Arnica
montana is the most commercially available (Moore 2011).
Commonly, Arnica has been used to treat inflammation and
prevent pain and bruising (Stevinson, et al. 2015). Internally, Arnica
has been used as an immuno-stimulant, and in the 20th Century was
used as a treatment for epilepsy and seasickness (EMEA 1999). Native
Americans had been known to use Arnica in ointments and
tinctures (Hocking 1945). In Europe, because the plant was thought
to possess bactericidal and fungicidal properties, it was used to
treat gunshot wounds and abrasions (Zeigler, et al. 1992).
The flowers of Arnica contain multiple therapeutic
components, including arnicin, volatile oil, resin, and tannins
(Willuhn 1972). More recently, it was discovered that the
anti-inflammatory properties of Arnica could actually be
attributed to sesquiterpenoid lactones (Levin & Willuhn 1987,
Merfort & Wendisch 1993). Although initially cultivated
for its flower heads, recent research has found that some medicinal
components are also found in the herb’s rhizome (Pljevljakusic, et
al. 2012). Aromatic hydrocarbons were found to predominantly
comprise the essential oils found in the rhizome and were further
identified as thymol derivatives (Pljevljakusic, et al. 2012).
Although, Arnica has been known to be used for wound healing
promotion and pharmacological concentrations and is supported by
several in vitro and clinical studies, investigations of
herbal homeopathic remedies on would healing processes are rare
(Hostanska, et al. 2012). In Hostanska et al.’s (2012) blind in
vitro trial of wound scratch closure of NIH 3T3 fibroblasts, Arnica
did not show an effect on cell viability and did not stimulate cell
proliferation (Hostanska, et al, 2012). In contrast, an in vivo
/ in vitro study found that when Arnica is
administered orally, it protects against hepatic mitochondrial
membrane permeabilization induced by calcium and iron due to the
fragmentation of proteins due to the attack of reactive oxygen
species (de Camargo, et al. 2013). In a clinical study done in a
post surgical setting for pain and inflammation, Arnica was
found to be more effective than a placebo for post-traumatic and
post-operative pain, edema, and ecchymosis (skin discoloring caused
by subcutaneous bleeding) (Iannitti, et al. 2014). Dosages and
preparations affected the efficacy of Arnica when treating
pain, edema, and ecchymosis (Iannitti, et al. 2014). For instance,
when given at higher dosages, Arnica was found to have side
effects that outweighed the benefits, but when given at the correct
dose, the efficacy improved and side effects decreased (Stevinson,
et al. 2003). Additionally, when taken orally, the efficacy
was lower than when used in a topical patch form (Barkey &
Kaszkin 2012). In another clinical study, oral Arnica
given pre-operatively was found to accelerate postoperative healing
and resolution of ecchymosis after osteotomies in rhinoplasty
surgery (Chaiet & Marcus. 2015). Conversely, Arnica
was found not to have any effect in the prevention of pain and
bruising in a placebo-controlled trial in hand surgery (Stevinson,
et al. 2003). However, Arnica in a topical patch form, 3x
diluted, was developed to alleviate pain and numbness in the hand
derived from cellulitis (Barkey & Kaszkin 2012). The Arnica
patch was found provide a significant reduction of pain and assisted
the hand to regain full functionality in a relatively short amount
of time (Barkey & Kaszkin 2012).
Interestingly, Arnica has additionally been found to cause
contact dermatitis and eczema when applied at excessive
concentrations (Lewis & Elvin-Lewis 2003). Despite its
immunosuppressive action, Arnica has been classified as a
plant with strong potency to induce allergic contact dermatitis
(Lass, et al. 2008). This reaction, immuno-stimulation, is caused by
the same sesquiterpenoid lactones that cause anti-inflammatory and
immunosuppressive responses when dosages are too low (Lass, et. al.
2008). The lack of adequate patch testing in cases of suspected
contact allergic dermatitis, incomplete or misleading product
labeling, and the risk of chemical adulteration may present further
concern regarding the application of botanical products, in this
specific case, Arnica products (Corazza, et al. 2009).
Overall, Arnica appears to be an effective treatment for
inflammation and ecchymosis. The benefits of taking Arnica
orally may be outweighed by the risks, and should be used more
commonly as a topical treatment. Additionally, too concentrated or
too diluted forms of Arnica topically can be harmful causing
allergic contact dermatitis and patient’s using this homeopathic
method should be made aware of possible side effects. Further,
patients should be aware that labeling on non-FDA approved bottles
may not be correctly dosed and/ or prepared. Though many conflicting
studies, it appears that Arnica may be useful to topically
treat edema and ecchymosis, specifically following surgery or
E. & M. Kaszkin.2012.
A homeopathic arnica patch for the relief of cellulitis-derived
pain and numbness in the hand. Glob Adv Health Med. 1(2): 18.20.
S.R. & B.C. Marcus. 2015. Preoperative Arnica montana
for reduction of ecchymosis in rhinoplasty surgery." Ann
Plast. Surg. 2015.5.
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remedies and cosmetics: a questionnaire-based investigation in
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administration homeopathic Arnica montana on mitochondrial
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W.H. & M.P.F. Elvin-Lewis. 2003. Medical Botany: Plants
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I. & D. Wendisch. 1992. New flavonoid glycosides from
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I. & D. Wendisch. 1993. Sesquiterpene lactones of Arnica
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D., M. Ristic, & D. Radanovic. 2012. Rhizome and root yield of
the cultivated Arnica montana L., chemical composition and
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2003. Homeopathic arnica for prevention of pain and bruising:
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roots, rhizoma, leaves and flowerheads of various Arnica
species. Planta Med. 21:329-342. Ziegler,
B., B. Michler, & C.G. Arnold. 1992. Arnica montana L.:
a protected plant as a source of a pharmacopoeia drug. Pharm.
Zeit. Wissen. 137:198-201. This paper was developed as part of the BIO 368 - Medical Botany
course offered at Wilkes University during the summer of 2015.
Course instructor was Kenneth M. Klemow, Ph.D. (firstname.lastname@example.org).
information contained herein is based on published sources, and is
made available for academic purposes only. No warrantees, expressed
or implied, are made about the medical usefulness or dangers
associated with the plant species in question.