Arnica

What Is Arnica?

Arnica is a flower found in mountainous regions of both Europe and North America.

It’s considered to be one of the best for treating injuries like broken bones, strains, sprains, and bruising.

It can prevent excessive fluid from leaking into the interstitial spaces, leading to bruising, swelling, and pain.

Most accounts don’t recommend arnica internally, and some case reports have suggested liver toxicity as a result.

As such, arnica shouldn’t be used on broken skin, which offers a direct route to the bloodstream, and eventually the liver.

Topical creams, salves, and liniments are typical methods of applying arnica and are a great thing to have around in a first aid kit.

What Is Arnica Used For?

Arnica is used for treating minor wounds, bruising, and inflammation of the skin. It makes for a great first aid herb.

Indications

• Bruises
• Sprains
• Muscle soreness/aches
• Chronic venous insufficiency
• Haemorrhoids
• Inflamed insect bites
• Haemotomas
• Oedema resulting from fracture
• Rheumatic arthritis
• Furunculosis
• Alopecia neurotica

Traditional Uses

Arnica has a long history of use for its anti-inflammatory, and vulnerary actions. It was mainly used for the treatment of sprains, bruises, hemotomas, and other injuries ^{4,5,9,10Reference 4Zheleva-Dimitrova D · 2012Antioxidant and acetylcholinesterase inhibitory potential of Arnica montana cultivated in BulgariaReference 5Wijnsma R et al. · 1995The importance of Arnica species in phytomedicineReference 9Auld CA et al. · 2006Novel effect of helenalin on Akt signaling and Skp2 expression in 3 T3-L1 preadipocytesReference 10Klaas CA et al. · 2002Studies on the anti-inflammatory activity of phytopharmaceuticals prepared from Arnica flowers}.

Botanical Information

Asteraceae is the largest of the flowering plant families with as much as 1911 genera (including Arnica), and 33,000 species.

Arnica has a rosette flower arrangement, with a flower stalk coming up from the center. The stalk can reach a height of 60 cm, and bears a yellow flower. ^{12Reference 12A modern herbal · 2016A modern herbal. (n.d.). Arnica. Retrieved August 13, 2016, from http://www.botanical.com/botanical/mgmh/a/arnic058.htmlView study →}.

Harvesting, Collection & Preparation

The flowering heads are often made into a macerated oil, or tincture and used topically ^{1Reference 1Battaglia · 2003The Complete Guide to Aromatherapy (2nd ed.)}.

Habitat, Ecology & Distribution

Arnica montana is mainly distributed in the mountainous regions of Europe ^{8Reference 8Craciunescu et al. · 2012Evaluation of antioxidant and cytoprotective activities of Arnica montana L. and Artemisia absinthium L. ethanolic extractsView study →} and North America.

Pharmacology & Medical Research

Alzheimer’s Disease

Acetylcholinesterase inhibitors are becoming a more popular method of treating and preventing neurodegenerative disorders such as Alzheimer’s. This condition is thought to be caused by the buildup of amyloid plaques in the synapses due to the breakdown of acetylcholine by the acetylcholinesterase enzymes. ^{6Reference 6Wattmo C et al. · 2016Mild versus moderate stages of Alzheimer’s disease: three-year outcomes in a routine clinical setting of cholinesterase inhibitor therapyView study →}. Modern Alzheimer’s treatments may use acetylcholinesterase inhibitors as a portion of the treatment.

Arnica montana flowerhead methanol extract has been shown to possess moderate anti-acetylcholinesterase activities in vitro ^{4Reference 4Zheleva-Dimitrova D · 2012Antioxidant and acetylcholinesterase inhibitory potential of Arnica montana cultivated in Bulgaria}. More information is needed to determine how this applies to a human subject.

Inflammation

The sesquiterpene lactone content of arnica is suggested to act on inflammation through immunological processes. Helenalin for example, a known anti-inflammatory agent and sesquiterpene lactone, is found in relevant concentrations in arnica along with several other closely related sesquiterpene lactones. ^{3Reference 3Hoffmann · 2003Medical herbalism: The science and practice of herbal medicine}. Several mechanisms of action are suggested from neutrophil modulation (cAMP, uncoupling of oxidative phosphorylation, inhibition of lysosomal activity), liver cell modulation (cAMP elevation, lysosomal enzyme inhibition), and inhibition of NF-kB ^{11Reference 11Bone · 2003A clinical guide to blending liquid herbs: Herbal formulations for the individual patient}.

Antioxidant

Arnica ethanolic extracts contain a high phenolic and flavonoid content which has been found to provide significant antioxidative and cytoprotective actions topically ^{8Reference 8Craciunescu et al. · 2012Evaluation of antioxidant and cytoprotective activities of Arnica montana L. and Artemisia absinthium L. ethanolic extractsView study →}.

Immunostimulation

The immunostimulating action of arnica is suggested to be due to the sesquiterpene lactone content, as well as a polysaccharide fraction which acts on phagocytosis ^{3Reference 3Hoffmann · 2003Medical herbalism: The science and practice of herbal medicine}.

Phytochemistry

Arnica’s pharmacology is dominated by its sesquiterpene lactones of the pseudoguaianolide type — chiefly helenalin and 11α,13-dihydrohelenalin, present as esters with tiglic, methacrylic, isobutyric and 2-methylbutyric acids ^{10,13Reference 10Klaas CA et al. · 2002Studies on the anti-inflammatory activity of phytopharmaceuticals prepared from Arnica flowersReference 13Perry et al. · 2009Sesquiterpene lactones in Arnica montana: Helenalin and dihydrohelenalin chemotypes in SpainView study →}. These are the anti-inflammatory principles (acting largely through inhibition of NF-κB) and also the chief toxic constituents, which is why arnica is restricted to external use ^{11,13Reference 11Bone · 2003A clinical guide to blending liquid herbs: Herbal formulations for the individual patientReference 13Perry et al. · 2009Sesquiterpene lactones in Arnica montana: Helenalin and dihydrohelenalin chemotypes in SpainView study →}. Helenalin in A. montana flowers runs in the order of 5–10 mg/g dry weight, with total sesquiterpene lactone content reaching roughly 0.3–1.5% of the dried flower head depending on origin and maturity ^{13,14Reference 13Perry et al. · 2009Sesquiterpene lactones in Arnica montana: Helenalin and dihydrohelenalin chemotypes in SpainView study →Reference 14Douglas et al. · 2004Sesquiterpene lactones in Arnica montana: a rapid analytical method and the effects of flower maturity and simulated mechanical harvesting on quality and yieldView study →}.

A second layer of activity comes from the flavonoids — including quercetin and its glycosides isoquercitrin, astragalin and rutin — which total about 0.4–0.6% of the dried flowers and contribute antioxidant and capillary-stabilising effects ^{8Reference 8Craciunescu et al. · 2012Evaluation of antioxidant and cytoprotective activities of Arnica montana L. and Artemisia absinthium L. ethanolic extractsView study →}. The flowers also carry an essential oil rich in thymol derivatives and fatty acids, plus coumarins, the bitter principle arnicin, and the storage carbohydrate inulin ^{12Reference 12A modern herbal · 2016A modern herbal. (n.d.). Arnica. Retrieved August 13, 2016, from http://www.botanical.com/botanical/mgmh/a/arnic058.htmlView study →}.

Constituent Summary

Figures are share of the dried flower head and vary widely with provenance, plant maturity and harvest method. † marks the two sesquiterpene-lactone types that define Arnica montana’s chemotypes: European populations split into helenalin-dominant and dihydrohelenalin-dominant chemotypes, and young flowers shift from helenalin- to dihydrohelenalin-rich as they mature ^{13,14Reference 13Perry et al. · 2009Sesquiterpene lactones in Arnica montana: Helenalin and dihydrohelenalin chemotypes in SpainView study →Reference 14Douglas et al. · 2004Sesquiterpene lactones in Arnica montana: a rapid analytical method and the effects of flower maturity and simulated mechanical harvesting on quality and yieldView study →}.

Clinical Applications

Arnica is used topically to heal minor wounds, bruising, and inflammation. It should not be used on broken skin or internally.

Cautions & Safety

There have been numerous case reports and older studies suggesting that arnica may be harmful to the liver if ingested internally. As a result, arnica is not recommended for use on open wounds or internally. The sesquiterpene lactones are suggested to be the main toxic constituent in arnica^{3Reference 3Hoffmann · 2003Medical herbalism: The science and practice of herbal medicine}.

The German Commission E Monographs recommend Arnica oil to be used in external applications only, and on injuries in which the skin is not broken ^{2Reference 2Blumenthal M · 1998ReviewThe complete German comission E Monographs: Therapeutic guide to herbal medicine}.

Avoid contact with the eyes.

The dermal LD50 of Arnica resinoid in rabbits was over 5g/kg in rabbits ^{7Reference 7Final Report on the Safety Assessment of et al. · 2001International Journal of Toxicology, 20(2), 1-11. doi:10.1080/10915810160233712View study →}.

The oral LD50 of Arnica montana extract was over 5g/kg and 123 mg/kg in rats and mice respectively ^{7Reference 7Final Report on the Safety Assessment of et al. · 2001International Journal of Toxicology, 20(2), 1-11. doi:10.1080/10915810160233712View study →}.

Arnica resinoid extract at 5 g/kg orally was shown to produce no negative side effects, and the LD50 of the resinoid was found to be over 5g/kg in rats.

Research into the phototoxicity of various Arnica extracts and mixtures were found to have no phototoxic effects ^{7Reference 7Final Report on the Safety Assessment of et al. · 2001International Journal of Toxicology, 20(2), 1-11. doi:10.1080/10915810160233712View study →}.

Contraindications

• Do not take internally

References

1. Battaglia, S. (2003). The Complete Guide to Aromatherapy (2nd ed.). Brisbane, Australia: The International Centre of Holistic Aromatherapy. (Pg 313)
2. Blumenthal M. (1998). The complete German comission E Monographs: Therapeutic guide to herbal medicine. American Botanical Council, USA.
3. Hoffmann, D. (2003). Medical herbalism: The science and practice of herbal medicine. Rochester, VT: Healing Arts Press. (Pg. 529-530)
4. Zheleva-Dimitrova D, Balabanova V. (2012). Antioxidant and acetylcholinesterase inhibitory potential of Arnica montana cultivated in Bulgaria. Turk J Biol. 36. 732-737.
5. Wijnsma R, Woerdenbag HJ, Busse W. (1995). The importance of Arnica species in phytomedicine. Z Phytother 16: 48−62, 1995.
6. Wattmo C, Minthon L, and Wallin A.K. (2016). Mild versus moderate stages of Alzheimer’s disease: three-year outcomes in a routine clinical setting of cholinesterase inhibitor therapy. Alzheimers Research & Therapy. 8:7. DOI: 10.1186/s13195-016-0174-1
7. Final Report on the Safety Assessment of Arnica Montana Extract and Arnica Montana. (2001). International Journal of Toxicology, 20(2), 1-11. doi:10.1080/10915810160233712
8. Craciunescu, O., Constantin, D., Gaspar, A., Toma, L., Utoiu, E., & Moldovan, L. (2012). Evaluation of antioxidant and cytoprotective activities of Arnica montana L. and Artemisia absinthium L. ethanolic extracts. Chemistry Central Journal, 6(1), 97. doi:10.1186/1752-153x-6-97
9. Auld CA, Hopkins RG, Fernandes KM, Morrison RF. (2006). Novel effect of helenalin on Akt signaling and Skp2 expression in 3 T3-L1 preadipocytes. Biochem Biophys Res Commun 2006, 346:314–320.
10. Klaas CA, Wagner G, Laufer S, Sosa S, Loggia R, Bomme U, Pahl HL, Merfort I. (2002). Studies on the anti-inflammatory activity of phytopharmaceuticals prepared from Arnica flowers. Planta Med 2002, 68:385–391.
11. Bone, K. (2003). A clinical guide to blending liquid herbs: Herbal formulations for the individual patient. Edinburgh [u.a.: Churchill Livingstone. (Pg. 70-72).
12. A modern herbal. (n.d.). Arnica. Retrieved August 13, 2016, from http://www.botanical.com/botanical/mgmh/a/arnic058.html
13. Perry, N. B., Burgess, E. J., Rodríguez Guitián, M. A., Romero Franco, R., López Mosquera, E., Smallfield, B. M., Joyce, N. I., & Littlejohn, R. P. (2009). Sesquiterpene lactones in Arnica montana: Helenalin and dihydrohelenalin chemotypes in Spain. Planta Medica, 75(6), 660-666. doi:10.1055/s-0029-1185362
14. Douglas, J. A., Smallfield, B. M., Burgess, E. J., Perry, N. B., Anderson, R. E., Douglas, M. H., & Glennie, V. L. (2004). Sesquiterpene lactones in Arnica montana: a rapid analytical method and the effects of flower maturity and simulated mechanical harvesting on quality and yield. Planta Medica, 70(2), 166-170. doi:10.1055/s-2004-815495