Click here for PDF version

Adulteration of Arnica (Arnica montana)

By Stefan Gafner, PhD^a*and Wendy Applequist, PhD^b

^aAmerican Botanical Council, PO Box 144345, Austin, TX 78714
^bMissouri Botanical Garden, PO Box 299, St. Louis, MO 63166

*Corresponding author: email

Keywords: Arnica montana, arnica flower, adulterant, adulteration, Heterotheca inuloides

Goal: The goal of this bulletin is to provide timely information and/or updates on issues of adulteration of Arnica montana flower to the international herbal products industry and extended natural products community in general. It is intended to present the available data on the occurrence of adulteration, the market situation, and consequences for the consumer and the industry.

1 General Information

1.1 Common name: Arnica¹

1.2 Other common names:

English: Leopard’s bane, European arnica, mountain tobacco, wolfsbane²†

Chinese: Shan jin hua (山金花)³

French: Arnica, arnique, bétoine des montagnes, herbe aux chutes, souci des alpes, tabac des Vosges²

German: Arnika, Berg-Wohlverleih, Engeltrank, Fallkraut, Wohlverleih, Wolfsblume²

Italian: Arnica²

Spanish: Arnica, tobaco de montana²

1.3 Accepted Latin binomial: Arnica montana¹

1.4 Botanical family: Asteraceae

1.5 Plant part and form: Arnica bulk raw material is usually sold as dried whole flowers, or in the form of dried flower extracts. Arnica tinctures (usually made with 50-70% aqueous ethanol) are sold for external use or as dietary supplements, although arnica is not recommended for oral use according to the American Herbal Products Association’s Botanical Safety Handbook, 2nd ed., the European Medicines Agency's (EMA) draft Community Herbal Monograph, and the monographs on Arnica Flower by the European Scientific Cooperative on Phytotherapy (ESCOP) and the German Commission E.^4-7 An exception is the use of arnica flower preparations in homeopathy, where highly diluted arnica tinctures in liquid form or tablets are popular. The predominant galenic form for arnica is as an ointment or a gel made with various concentrations of arnica tincture. Arnica ointments are sold mainly as homeopathic remedies (although in most preparations, the arnica tincture is undiluted^‡), or as herbal ointments in combination with other ingredients. Arnica is also a popular ingredient in massage oils and in cosmetic preparations.

1.6 General use(s): Traditionally, arnica tinctures, gels, creams, and ointments containing arnica oil, tinctures, or liquid extracts (liquid extracts are made using a 1:20 ratio of fresh flowers to 50% aqueous ethanol) are used topically for the relief of bruises, sprains, and localized muscular pain.⁶ The World Health Organization monograph lists the treatment of pain and inflammation (bruises and other types of injuries leading to hematomas [localized bleeds visible under the surface of the skin]) resulting from minor injuries and accidents, and the treatment of inflammation of the oral mucous membranes, insect bites, and superficial phlebitis as indications for arnica.⁸ The essential oil, flower water, or extracts of arnica are used in the cosmetic industry as a fragrance, or as a skin-conditioning agent.⁹

2 Market

2.1 Importance in the trade: The use of arnica as an ingredient in dietary supplements is not extensive, as it is not recommended for internal use.^4,5 Ingestion of non-homeopathic arnica preparations can result in cardiac, pulmonary, and uterine toxicity (see section 3.5 below), and can cause gastrointestinal disorders.^5,10 However, the herb is popular as an ingredient in ointments and gels. According to the market research company SPINS, sales of arnica in the herbal category (according to SPINS, herbal tinctures, e.g., arnica tinctures labeled “for external use only”, and loose herbs do not have to bear a dietary supplement statement on their labels to be captured under the herbal category) have been increasing between 2012 and 2014 (Table 1), with ca. 65–75% of sales in the Mainstream Multi-Outlet retail channel in the United States, where arnica ranked between #83 and #113. (T. Smith [American Botanical Council] e-mail, September 2, 2015 and September 3, 2015). Sales of topical arnica ointments and gels were in the range of US $15–25 million in the years 2013–2015 (Table 2), with a healthy year-to-year sales increase (K. Kawa [SPINS] e-mail, February 25, 2016 and February 29, 2016). The ranking of topical arnica preparations compared to other homeopathic products is not available.

Table 1: Sales data for arnica (including bulk herbs and tinctures) in the herbal category in the United States from 2012-2014.

Channel	2012		2013		2014
	Rank	Sales [US$]	Rank	Sales [US$]	Rank	Sales [US$]
Naturala	189	59,044	182	85,813	176	125,246
Mainstream Multi-Outletb	102	135,583	113	161,936	83	384,485

Table 2: Sales [in US$] data for topical arnica preparations (sold as homeopathic remedies) in the United States from 2012-2015.

Channel	2012	2013	2014	2015
Naturala	3,814,350	4,112,825	4,257,750	4,184,862
Mainstream Multi-Outletb	n/a	12,281,389	16,770,345	18,710,056

^{aAccording to SPINS (SPINS does not track sales at Whole Foods Market, which is a major natural products retailer in the US, health professionals, or other outlets without scanners
bAccording to SPINS (the Mainstream Multi-Outlet channel was formerly known as food, drug and mass market channel [FDM], exclusive of sales at Walmart)
n/a: not available
Source: T. Smith (American Botanical Council) e-mail, September 2, 2015 and September 3, 2015; K. Kawa (SPINS) e-mail, February 25, 2016 and February 29, 2016.}

2.2 Supply sources: Arnica montana is native to Europe; its range extends from Scandinavia across central Europe to Spain and Portugal, and eastward to the Balkan peninsula, Poland, Romania, Ukraine, and southern Russia. A report from 1998 suggests that Europe alone uses ca. 50 metric tons of dried arnica flowers (equivalent to 250–350 tons of fresh flowers) per year.¹¹ The same harvest volume is also cited in 2010 by Cropwatch, an independent organization assessing the status of threatened medicinal and aromatic plants.¹² Most commercial material is obtained from collections in the wild in Romania, Spain, and countries of the western Balkans.^13,14 Cultivation is possible, but is difficult and more costly than collection in the wild.¹⁴ Results of an assessment of the arnica supply chain, commissioned by the World Wildlife Fund, were published in 2006. According to these data, harvesters received €0.28/kg (1€ was equivalent to US $1.18-1.32 in 2006) for fresh arnica flowers, while intermediary collectors obtained €0.38/kg. After drying, arnica flowers were sold for ca. €10/kg to wholesale manufacturers. Prices at wholesale reached €25-28/kg, depending on the market (domestic versus export).¹⁵ These prices are in line with wholesale prices in 2006 from Australia, where material sold for US $28–40/kg. In the past years, prices for sustainably wildcrafted bulk arnica flowers (minimum quantity of 500 kg) varied from €20 to €40/kg (US$22.5 to $45/kg based on the exchange rate on June 15, 2016) for Central European material and from €30 to €50/kg (US$34 to $57/kg) for Spanish material, depending on year and supplier (K.W. Quirin [Flavex] e-mail communication, May 25, 2016).

2.3 Raw material forms: Bulk arnica raw material is sold mainly as whole dried flowers. Other plant parts, e.g., the whole herb and the roots, are also sold. However, whole arnica herb or roots are not within the scope of this document.

2.4 Market dynamics: According to sales data of the past four years (Tables 1 and 2), there has been a steady increase in sales of arnica-based products in the United States. Sales data from other countries are not available. Pricing for the consumer is in the range of US $99-216/kg for whole dried arnica flowers, according to an informal survey of smaller companies in the United States and Germany that had pricing listed on the internet, conducted for this Bulletin (SG). Dried whole flowers of A. chamissionis and false, or Mexican, arnica (Heterotheca inuloides, Asteraceae), were listed at US $74-117/kg and US $18-37/kg, respectively.

3 Adulteration

3.1 Known adulterants: Currently, A. montana is the only official species listed in the European Pharmacopoeia.¹⁶ However, other Arnica species, i.e., A. angustifolia, A. chamissonis, A. chamissonis subsp. foliosa, A. cordifolia, A. latifolia, and A. sororia, may legally be sold in the United States under the Standardized Common Name of “arnica”, according to the second edition of the American Herbal Products Association’s Herbs of Commerce.^1§ North America has the greatest natural diversity of Arnica species with 26 of 29 species within the genus.¹⁷ The most common adulteration-related issue in the arnica trade is the replacement of arnica flowers with flowers of so-called “Mexican arnica” (predominantly Heterotheca spp.). In addition, other species known as “arnica”, especially in the Southern United States and Mexico, are offered on the market. These species include members of the Asteraceae (Gaillardia spp., Grindelia spp., Helenium mexicanum, Heterotheca leptoglossa, H. subaxillaris, Jefea pringlei, Neurolaena lobata, Pseudogynoxys spp., Tithonia diversifolia, Trixis angustifolia, T. inula, T. radialis, Verbesina crocata, V. pinnatifida), and Loasaceae (Mentzelia conzattii).^18,19 Adulteration with other yellow-flowering species of the Asteraceae (Calendula officinalis, Cota tinctoria, Doronicum pardalianches, and Inula britannica) is reported in older textbooks, but a mixture of these species with arnica flowers has not been reported in the current market.²⁰

3.2 Sources of information supporting confirmation of adulteration: Adulteration of arnica with H. inuloides was noted in mid-twentieth-century pharmacognostic literature.²¹ European literature states that it had been frequent in the 1990s.^22-24 A 2012 study of bulk herbs sold by online retailers and two stores in the St. Louis, Missouri area reported that of 11 samples of unprocessed whole “arnica flower” obtained from US-based vendors of bulk herbs, six were Heterotheca rather than genuine arnica.²⁵

3.3 Accidental or intentional adulteration: Due to overharvesting, arnica has been protected in a number of European countries, but populations are still in decline.^26,27 The relatively high price of A. montana flowers, compared to H. inuloides, has provided an incentive for economically-motivated adulteration. At the same time, other species of Arnica, or members of the family Asteraceae colloquially known as arnica, are interchangeably used by local herbalists for the same benefits as A. montana. In addition, A. chamissonis subsp. foliosa was approved by the German Commission E in 1984 as a substitute for A. montana for external use in preparations for treating muscle and joint injuries, and for inflammation of the oral cavity and the throat.⁵ However, the species A. chamissonis subsp. foliosa is currently not included in the European Pharmacopoeia.¹⁶

3.4 Frequency of occurrence: There is no comprehensive published study on the frequency of arnica adulteration, but information from limited publications to date indicates that adulteration is common.

3.5 Possible safety/therapeutic issues: Adulteration of arnica with H. inuloides is economic in nature and creates no apparent safety concern. Traditional uses of the latter are similar to those of the former. However, H. inuloides is also used internally without the cautions regarding toxicity that are usually expressed for arnica,^28,29 which is contraindicated for ingestion.^4,30

Heterotheca inuloides contains cytotoxic compounds, but a recent study reported that a dose of 2,000 mg/kg of the predominant sesquiterpene, 7-hydroxy-3,4-dihydrocadalene, was required to produce evidence of acute toxicity in mice.³¹ The occurrence of allergic reactions and contact dermatitis after topical administration of arnica is well documented,^4,32 but a comprehensive literature search has not revealed any such adverse event description for H. inuloides.

3.6 Analytical methods to detect adulteration: When present as whole dried flower, A. montana is readily distinguished from H. inuloides and C. officinalis using morphological characteristics.^24,25 Arnica and calendula can also be differentiated using botanical microscopy.^33,34 In addition, microscopic features to distinguish between A. montana and H. inuloides flowers have been detailed by Saukel.³⁵ However, a literature search has not located a comparison of the microscopic characteristics of the various other Arnica spp. The HPTLC Association has published a high-performance thin-layer chromatography (HPTLC) method with criteria to distinguish A. montana from A. chamissonis, C. officinalis, and H. inuloides.³⁶ A TLC method using the same solvent system is described in the European Pharmacopoeia.¹⁶ Chemical distinction among A. montana, A. chamissonis, and H. inuloides has also been achieved by Schröder and Merfort (1991) using high-performance liquid chromatography combined with mass spectrometry (HPLC-MS),³⁷ although more recent liquid chromatography methods to analyze flavonoids, caffeoylquinic acids, and sesquiterpene lactones are available.^16,38-40 The sesquiterpene composition reportedly depends on the geographical origin of the flowers, with materials from Central Europe predominantly containing helenalin esters while flowers from Spain are characterized by the abundance of 11α,13-dihydrohelenalin esters.^24,41 Finally, DNA barcoding using the matK and rbcL sequences was performed to authenticate four dried crude materials labeled as “arnica” sold in yerberías and supermarkets in the Rio Grande Valley in Texas. The method could successfully distinguish authentic A. montana from the commercial samples, which were identified as Grindelia spp., Heterotheca subaxillaris, Pseudogynoxys spp., and Trixis inula.¹⁹

4 Conclusions

Economic adulteration of arnica with less costly species, especially H. inuloides, remains an occurrence of which purchasers must be aware. Adulteration of arnica with H. inuloides is readily detected using macroscopic, microscopic, chemical analysis, and/or DNA analysis.

^{†The occasional common name ‘wolfsbane’ for arnica in some locations should not be confused with the more widespread use of the common name wolfsbane to refer to the toxic plants in the genusAconitum(Ranunculaceae).}

^‡Such undiluted tinctures in homeopathy are referred to as a ‘mother tincture’ and must conform to specifications for raw material and method of preparation found in officially recognized homeopathic pharmacopeias.

^§The first edition of the American Herbal Products Association’s Herbs of Commerce lists A. montana and A. latifolia as the only species in commerce with arnica as the common name. The first edition of Herbs of Commerce was incorporated by reference in the U.S. Food and Drug Administration's (FDA) rules for labeling dietary supplements in 1997. This regulation was codified at 21 CFR 101.4 (h), but codification has not been updated to include the second edition of Herbs of Commerce.

5 References

1. McGuffin M, Kartesz JT, Leung AY, Tucker AO. American Herbal Products Association’s Herbs of Commerce. 2^nd ed. Silver Spring, MD: American Herbal Products Association; 2000.
2. Ladner J. Arnica montana. In: Grassland species profile. Food and Agriculture Organization (FAO) of the United Nations website. Available at: http://www.fao.org/ag/agp/agpc/doc/gbase/data/pf000462.htm. Accessed March 17, 2016.
3. Flora of China. eFloras.org website. Available at: http://www.efloras.org. Accessed March 17, 2016.
4. Gardner Z, McGuffin M. American Herbal Products Association’s Botanical Safety Handbook. 2^nd ed. Boca Raton, FL: CRC Press; 2013.
5. Blumenthal M, Goldberg A, Brinckmann J, eds. Herbal Medicine: Expanded Commission E Monographs. Austin, TX: American Botanical Council; Newton, MA: Integrative Medicine Communications; 2000.
6. European Medicines Agency: Draft community herbal monograph on Arnica montana L., flos. 2014. Available at: http://www.ema.europa.eu/docs/en_GB/document_library/Herbal_-_Community_herbal_monograph/2013/08/WC500148263.pdf. Accessed March 17, 2016.
7. Arnicae flos. European Scientific Cooperative on Phytotherapy. ESCOP Monographs. 2nd ed. New York: Thieme New York; 2003.
8. World Health Organization. WHO Monographs on Selected Plants, Volume 3. Flos Arnicae. Geneva, Switzerland: WHO Press; 2007:77-87.
9. European Commission Health & Consumers Directorate. Cosmetic Ingredients and Substances (CosIng^®) Database. Brussels, Belgium: European Commission. Available at: http://ec.europa.eu/consumers/cosmetics/cosing. Accessed March 17, 2016.
10. Schulz V, Hänsel R. Rationale Phytotherapie. 4^th ed. Berlin, Germany: Springer Verlag; 1999:324-325.
11. Lange D. Europe's medicinal and aromatic plants: their use, trade and conservation. Cambridge, United Kingdom: TRAFFIC International; 1998:73.
12. Burfield T. Arnica - Updated list of threatened aromatic plants used in the aroma & cosmetic industries, V1.21 Mar. 2010. Assembles from several Cropwatch sources. Published 2003-2010. Corrected and revised March 2010.
13. Engels G, Brinckmann J. Arnica. HerbalGram. 2015;107:1-7.
14. Kathe W. Conservation of Eastern-European medicinal plants: Arnica montana in Romania. In: Bogers RJ, Craker LE, Lange D, eds. Medicinal and Aromatic Plants, Agricultural, Commercial, Economic, Legal, Pharmacological and Social Aspects. Vol. 17. Dordrecht, The Netherlands: Springer-Verlag; 2006: 203-211.
15. Michler B. Conservation of Eastern European medicinal plants: Arnica montana in Romania. Case study Gârda de Sus: Management plan. Surrey, United Kingdom: World Wildlife Fund; 2007.
16. The European Directorate for the Quality of Medicines and HealthCare. European Pharmacopoeia (EP 8.4). Arnicae flos. Strasbourg, France: Council of Europe; 2014.
17. Arnica. Flora of North America website. Available at: http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=102636. Accessed July 5, 2016.
18. Waizel-Bucay J, de Lourdes Cruz-Juárez M. Arnica montana L., planta medicinal europea con relevancia. Rev Mex Cienc Forest. 2014;5(25):98-109.
19. Aguilar de Alba HG. Development of a DNA barcoding reference library for identification of medicinal plant materials used in the Rio Grande Valley in Texas: a representative case study using Arnica (Asteraceae). MSc thesis. Brownsville TX: University of Texas at Brownsville, Dissertations in Biology; 2015. Available at: https://repositories.tdl.org/utb-ir/bitstream/handle/2152.6/703/Aguilar_Hector_%20Thesis_9-23-15.pdf?sequence=1&isAllowed=y. Accessed March 17, 2016.
20. Merfort I, Willuhn G, Jerga C. Arnikablüten DAB9 – Reinheitsprüfung. Deutsche Apotheker Zeitung. 1990;130(18):980-984.
21. Youngken H. Textbook of Pharmacognosy, 5^th ed. Philadelphia, PA: The Blakiston Company; 1943.
22. Schilcher H. Probleme bei der Beschaffung von Drogen mit Arzneibuchqualität. Pharm Ztg. 1981;126:2119-2128.
23. Pietta PG, Mauri PL, Bruno A, Merfort I. MEKC as an improved method to detect falsifications in the flowers of Arnica montana and A. chamissonis. Planta Med. 1994;60:369-372.
24. Willuhn G. Arnicae flos – Arnica flowers. In: Wichtl M, ed. Brinckmann JA, Lindenmaier MP, trans. Herbal Drugs and Phytopharmaceuticals. 3rd ed. Stuttgart: Medpharm GmbH Scientific Publishers; 2004:54-59.
25. Walker K, Applequist W. Adulteration of selected unprocessed botanicals in the U.S. retail herbal trade. Econ Bot. 2014;66(4):321-327.
26. Falniowski, A., Bazos, I., Hodálová, I., Lansdown, R, Petrova, A. 2013. Arnica montana. The IUCN Red List of Threatened Species 2013: e.T162327A5574104.Available at: http://dx.doi.org/10.2305/IUCN.UK.2011-1.RLTS.T162327A5574104.en. Accessed February 24, 2016.
27. Cech R. Arnica and Arnica analogues. Journal of Medicinal Plant Conservation. 2013;6-7.
28. González Elizondo M, López Enriquez IL, González Elizondo MS, Tena Flores JA. Plantas Medicinales del Estado de Durango y Zonas Aledañas. Tresguerras, Mexico: Instituto Politécnico Nacional; 2004.
29. Moreno Uribe V, ed. Herbolaria y Tradición en la Región de Xico, Veracruz. [Xalapa, Mexico]: Consejo Veracruzano de Arte popular; 2004.
30. Mills S, Bone K, eds. The Essential Guide to Herbal Safety. St. Louis, MO: Elsevier, Inc.; 2005:245-248.
31. Rodriguez-Chávez JL, Coballase-Urrutia E, Sicilia-Argumedo G, Ramirez-Apan T, Delgado G. Toxicological evaluation of the natural products and some semisynthetic derivatives of Heterotheca inuloides Cass (Asteraceae). J Ethnopharmacol. 2015;175:256-265.
32. Iannitti T, Morales-Medina JC, Bellavite P, Rottigni V, Palmieri B. Effectiveness and safety of Arnica montana in post-surgical setting, pain and inflammation. Am J Ther. 2016;23(1):e184-e197.
33. Upton R, Graff A, Jolliffe G, Länger R, Williamson E, eds. American Herbal Pharmacopoeia: Botanical Pharmacognosy – Microscopic Characterization of Botanical Medicines. Boca Raton, FL: CRC Press; 2011.
34. Eschrich W, ed. Pulver-Atlas der Drogen. 7^th ed. Stuttgart, Germany: Deutscher Apotheker Verlag; 1999:234-235.
35. Saukel J. Pharmakobotanische Untersuchungen von Arzneidrogen III. Unterscheidungsmerkmale der Blütendrogen von Arnica montana L. und Heterotheca inuloides Cass. Sci Pharm. 1984;52:35-46.
36. International Association for the Advancement of High Performance Thin Layer Chromatography. Arnica montana (arnica flower). July 21, 2014. Available at: http://www.hptlc-association.org/methods.cfm. Accessed March 16, 2016.
37. Schröder E, Merfort I. Thermospray liquid chromatographic/mass spectrometric studies of flavonol glycosides from Arnica montana and Arnica chamissionis extracts. Biol Mass Spectrom. 1991;20(1):11-20.
38. Stefanache CP, Peter S, Meier B, Danila D, Tanase C, Wolfram E. Phytochemical composition of Arnicae flos from wild populations in the northern area of the Romanian eastern Carpathians. Rev Chim (Bucharest). 2015;66(5):784-787.
39. Zheleva-Dimitrova DZ, Balabanova V, Gevrenova R, Doytchinova I, Vltkova A. Chemometrics-based approach in analysis of Arnicae flos. Phcog Mag. 2015;11:538-544.
40. Lin LZ, Harnly JM. Identification of hydroxycinnamoylquinic acids of arnica flowers and burdock roots using a standardized LC-DAD-ESI/MS profiling method. J Agr Food Chem. 2008;56(21):10105-10114.
41. May P. Arnica flower CO₂-extract – approved efficacy in topical treatment. Cosmetic Science Technology. 2013;1-6. 

Version # , Author,	Date Revised	Section Revised	List of Changes
Version 1, S. Gafner, W. Applequist	n/a	n/a	None