Herbal Medicine: Expanded Commission E
Usnea
|
Latin Name: Usnea barbata, U. florida, U. hirta, U. plicata
Pharmacopeial Name: Usnea species
Other Names: beard-moss, old man's beard, tree moss, usnea lichen
Overview
Usnea is not a plant but rather a fruticose lichena combination of two kinds of organisms, fungus and alga, growing in a symbiotic union. Some Usnea species reproduce by soredia, whereby a moldlike fungus captures and entraps microscopic green algae, resulting in a new stable thallus of a specific structure with no resemblance to its fungal or algal antecedents. Usnea has vague species limits with considerable morphological variation within single populations, making species identification difficult or even impossible. It grows on the bark and wood of coniferous (e.g., Douglas fir and ponderosa pine) and deciduous hardwood (e.g., oak, and apple and other fruit trees) host trees in orchards and damp forests throughout the northern hemisphere in Asia, Europe, and North America (Hale and Cole, 1988; Hobbs, 1986; Kjeldsen, 1997). Usnea lichen prefers old-growth trees and its habitat is diminishing due to logging (Cabrera, 1996). It is almost depleted from many natural locations and has now been put under protected status in Germany, where it is listed in Annex 1 of the German Federal Ordinance on the Conservation of Species (BArtSchV) whereby a permit is necessary for both import and export of any wild collected material (Lange and Schippmann, 1997). Germany has imported most of its Usnea barbata supply from Indonesia up through 1991 (Lange and Schippmann, 1997), though German importers have been sourcing from the Pacific Northwest of North America since at least 1992. The government of Nepal has recently placed some lichens, including U. barbata, under protected status, banning its export in unprocessed forms (Bhattarai, 1999). Usnea is used today in traditional Chinese medicine, contemporary homeopathic and naturopathic medicines, and in various systems of traditional medicine worldwide (Sharnoff and Sharnoff, 1998). The current genus name Usnea is not in the literature of the ancient Greeks or Romans and may have originated at the time of the Arabian school of medicine and pharmacy. The Formulary of Al-Kindi (ca. 850 C.E.) calls Alectoria usneoides 'ushna' (Cabrera, 1996; Hobbs, 1986; Levey, 1966). Usnea lichen has a recorded history of therapeutic use dating back over three thousand years in Chinese medicine (Cabrera, 1996; Tilford, 1997). Early Chinese herbalists reported the oral ingestion of U. longissima to have expectorant action and also indicated its topical application in powder form to treat surface infections or external ulcers. It is still in use today in tincture form to treat tuberculosis lymphedenitis (Cabrera, 1996; Hobbs, 1986). U. diffracta Vain. is used today in Chinese, Japanese, and Korean medicines. In China, it is prepared as an aqueous decoction for oral ingestion to treat pulmonary tuberculosis and chronic bronchitis. For topical application, in decoction or powder form, it is also used to treat infectious wounds. In Japan and Korea the decoction is used to treat scrofula and swelling, among other conditions (But et al., 1997). In the former Soviet Far East, U. filipendula is used as a topical powder to treat wounds. This material has tested positive for antibacterial activity (Sharnoff and Sharnoff, 1998). In North American aboriginal medicines usnea is used as an expectorant drug (Kjeldsen, 1997). Additionally, the Nitinaht people use U. longissima externally as a wound dressing material and the Makah people use it as a dermatological aid for boils (Moerman, 1998). In Germany, usnea is approved in the Commission E monographs and its preparations are used for mild inflammation of the oral and pharyngeal mucosa. It is usually taken in lozenge form (BAnz, 1998). In the United States, it is dispensed by licensed practitioners (e.g., acupuncturists and naturopaths) to treat urinary tract infections and upper respiratory infections, usually in an alcoholic fluidextract dosage form (Hobbs, 1986). Usnea longissima, U. florida,U. diffracta, and U. barbata are the species most commonly used by North American medical herbalists, though other local species are also used comparably. It is orally ingested as an aqueous infusion and alcoholic tincture to treat lung infections, tuberculosis, urinary tract infections, Candida albicans, and strep throat (Summers, 1998). Usnea is also the most common source material for antibiotic and antifungal lichen acids, particularly usnic acid (Hobbs, 1986), which is used as a component in antibiotic salves and deodorants (Sharnoff and Sharnoff, 1998). Usnea barbata is classified in the Homeopathic Pharmacopoeia of the United States (HPUS) as an OTC Class C drug prepared as a 1:10 (w/v) alcoholic tincture, in 65% v/v alcohol, and is used by homeopaths for headaches and sunstroke (Cabrera, 1996; Hobbs, 1986; HPUS, 1992). It is used by naturopaths to treat bronchitis, pleurisy, and other respiratory infections, as well as urinary tract, kidney, and bladder infections (HRPI, 1995). Usnea lichens are also used as biological indicators of air quality, due to their measurable uptake and bioaccumulation of toxic pollutants. Lichens are like sponges that absorb much of which they are in contact. Most lichens are extremely vulnerable to air pollution. When lichens disappear, they give early warning of harmful conditions. Lichen sensitivity can vary with climate, the composition and proportion of airborne pollutants, and topographic exposure. Lichens can be used to monitor levels of sulfur dioxide and a number of toxic metals. Lichens accumulate lead in particular and acid rain appears to affect lichen propagules severely (Kjeldsen, 1997; Popblet et al., 1997; Sharnoff and Sharnoff, 1998). Usnea lichens and/or their isolated derivatives have been the subject of several pharmacological studies due to their old medical uses in European medicine (Dobrescu et al., 1993). The approved modern therapeutic applications for usnea are supportable based on its history of use in well established systems of traditional and conventional medicines, extensive phytochemical investigations, and pharmacological studies.
Description
Usnea consists of the dried thallus of Usnea species, primarily U. barbata (L.) Wiggers emend. Mot., U. florida (L.) Fries, U. hirta (L.) Hoffmann and U. plicata (L.) Fries [Fam. Usneaceae] and preparations of Usnea in effective dosage. The herb contains lichenic acid.
Chemistry and Pharmacology
Usnea contains lichenic acids, including usnic acid and its derivatives, diffractaic acid (Budavari, 1996; But et al., 1997); other lichenic acids including barbatic and lobaric acids; vitamin C (Hobbs, 1986); fatty acids, including linoleic, oleic, and arachidonic acids; and sterols (But et al., 1997). The Commission E reported antimicrobial activity. U. barbata contains usnic acid, which has demonstrated a broad antibiotic spectrum (Dobrescu et al., 1993). Usnic acid and diffractaic acid, isolated from U. diffracta, have both demonstrated analgesic action in mice (Okuyama et al., 1995). Fractions containing usnic acid and isolichenin, isolated from U. fasciata, have demonstrated moderate activity against sarcoma 180 and Ehrlich tumor cells (Periera et al., 1994).
Uses
The Commission E approved usnea for mild inflammations of the oral and pharyngeal mucosa. Usnea preparations are used clinically by North American herbalists for antibacterial action against gram positive bacteria in local or systemic infections and for antifungal action against Candida albicans (Cabrera, 1996).
Contraindications
None known.
Side Effects
None known.
Use During Pregnancy and Lactation
No restrictions known.
Interactions with Other Drugs
None known.
Dosage and Administration
Unless otherwise prescribed: Preparations of herb for lozenges and equivalent solid forms of medication. Lozenges with preparations equivalent to 100 mg herb: 1 lozenge, three to six times daily (Commission E). Tincture, 1:3 (g/ml), 70% alcohol: 3 ml, three times daily (Cabrera, 1996).
References
BAnz. See Bundesanzeiger. Bhattarai, N.K. 1999. Medicinal plants and the Plant Research Division of Nepal. Med Plant Conserv 5:78. Budavari, S. (ed.). 1996. The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals, 12th ed. Whitehouse Station, N.J.: Merck & Co, Inc. 1687. Bundesanzeiger (BAnz). 1998. Monographien der Kommission E (Zulassungs- und Aufbereitungskommission am BGA f r den humanmed. Bereich, phytotherapeutische Therapierichtung und Stoffgruppe). Kln: Bundesgesundheitsamt (BGA). But, P.P.H. et al. (eds.). 1997. International Collation of Traditional and Folk Medicine. Singapore: World Scientific. 67. Cabrera, C. 1996. Materia MedicaUsnea spp. Eur J Herbal Med 2(2):1113. Dobrescu, D. et al. 1993. Contributions to the complex study of some lichensUsnea genus. Pharmacological studies on Usnea barbata and Usnea hirta species. Rom J Physiol 30(12):101107. Hale, M.E. and M. Cole. 1988. Lichens of California. Berkeley, CA: University of California Press. Herbal Research Publications, Inc. (HRPI). 1995. Naturopathic Handbook of Herbal Formulas: A Practical and Concise Herb User's Guide. Ayer, MA: Herbal Research Publications, Inc. 124. Hobbs, C. 1986. Usnea: The Herbal Antibiotic. Capitola, CA: Botanica Press. The Homeopathic Pharmacopoeia of the United States (HPUS). 1992. Arlington, VA: Pharmacopoeia Convention of the American Institute of Homeopathy. Kjeldsen, C. 1997. MycologyBiology 339 Sonoma State University. Oklahoma City, OK: Custom Academic Publishing Company (CAPCO). 2332. Lange, D. and U. Schippmann. 1997. Trade Survey of Medicinal Plants in GermanyA Contribution to International Plant Species Conservation. Bonn: Bundesamt f r Naturschutz. 93, 115120. Levey, M. 1966. The Medical Formulary or Agrabadhin or Al-Kindi. Madison, WI: University of Wisconsin Press. Moerman, D.E. 1998. Native American Ethnobotany. Portland, OR: Timber Press. 582. Okuyama, E., K. Umeyama, M. Yamazaki, Y. Kinoshita, Y. Yamamoto. 1995. Usnic acid and diffractaic acid as analgesic and antipyretic components of Usnea diffracta. Planta Med 61(2):113115. Periera, E.C. et al. 1994. Analysis of Usnea fasciata crude extracts with antineoplastic activity. Tokai J Exp Clin Med 19(12):4752. Poblet, A. et al. 1997. The use of epilithic Antarctic lichens (Usnea aurantiacoatra and U. antartica) to determine deposition patterns of heavy metals in the Shetland Islands, Antarctica. Sci Total Environ 207(23):187194. Sharnoff, S. and S. Sharnoff. 1998. North American Lichen Project. Available at: www.lichen.com/home.html Summers, A. 1998. Ethnobotany of Some Common Lichens of Northern California. Rohnert Park, CA: Unpublished paper prepared for Mycology Biology 339 Course: Sonoma State University. Tilford, G.L. 1997. Edible and Medicinal Plants of the West. Missoula, MT: Mountain Press Publishing Company. 148149.
Additional Resources
Bolton, E.M. 1960. Lichens for Vegetable Dyeing. London: Studio Books. Richardson, D.H.S. 1975. The Vanishing Lichens. Vancouver: David and Charles. This material was adapted from The Complete German Commission E MonographsTherapeutic Guide to Herbal Medicines. M. Blumenthal, W.R. Busse, A. Goldberg, J. Gruenwald, T. Hall, C.W. Riggins, R.S. Rister (eds.) S. Klein and R.S. Rister (trans.). 1998. Austin: American Botanical Council; Boston: Integrative Medicine Communications.
1) The Overview section is new information. 2) Description, Chemistry and Pharmacology, Uses, Contraindications, Side Effects, Interactions with Other Drugs, and Dosage sections have been drawn from the original work. Additional information has been added in some or all of these sections, as noted with references. 3) The dosage for equivalent preparations (tea infusion, fluidextract, and tincture) have been provided based on the following example: - Unless otherwise prescribed: 2 g per day of [powdered, crushed, cut or whole] [plant part]
- Infusion: 2 g in 150 ml of water
- Fluidextract 1:1 (g/ml): 2 ml
- Tincture 1:5 (g/ml): 10 ml
4) The References and Additional Resources sections are new sections. Additional Resources are not cited in the monograph but are included for research purposes. This monograph, published by the Commission E in 1994, was modified based on new scientific research. It contains more extensive pharmacological and therapeutic information taken directly from the Commission E.
Excerpt from Herbal Medicine: Expanded Commission E Monographs
Copyright 2000 American Botanical Council
Published by Integrative Medicine Communications
Available from the American Botanical Council.
|
|