Echinacea is a genus of eastern North American flowering plants in the family, Asteraceae. There are perhaps nine species of echinacea, including Echinacea purpurea, E. angustifolia, and E. pallida, popular garden ornamentals.The purple coneflower, Echinacea purpurea, is a drought-tolerant perennial with daisy-like purple flowers (florets) arranged in a prominent, cone-shaped head; "cone-shaped" because the ray florets tend to point out and down (are decumbant) as the flower head opens.

Herbal remedy

Echinacea rhizome was used by North American Plains Indians, perhaps more than most other species used for making herbal remedies. In the 1930s it became popular in both Europe and America as a folk medicine. Echinacea has been attributed with the ability to boost the body's immune system and ward off infections and as such could be useful in the treatment of:

• Colds, coughs and flu and other upper respiratory conditions
• Enlarged lymph glands, sore throat
• Urinary tract infections
• Other minor infections
• Herpes and candida
• Wounds, skin regeneration and skin infections (external use)
• Psoriasis, eczema and inflammatory skin conditions (external use)

Depending on which species is used, herbal medicinals can be prepared from the above-ground parts and/or the root. It is not known which of echinacea's many chemical components might be responsible for touted health benefits, although all species possess compounds of a chemical class called "phenols" (as do most other plants). Cichoric and caftaric acids are phenols that are present throughout E.. purpurea; echinacoside is a phenol found in higher levels within E. angustifolia and E. pallida roots. When making herbal remedies, these phenols can serve as markers to evaluate the quantity of echinacea in the product. Other constituents that may be important include alkamides and polysaccharides.

A medical study by Taylor et al. (2003) demonstrated that echinacea products made from the entire plant (not just the root), and taken after the second cold symptom appeared, provided no measurable beneficial effect for children in treating the severity or duration of symptoms caused by the common cold virus. Studies by the University of Virginia School of Medicine (Turner, 2005) confirmed these results, and added that Echinacea had no clinically significant effects on the common cold even if taken immediately upon infection, or as a prophylaxis starting a week prior to symptoms of infection. However, it should be noted that this study was criticized for using lower than recommended doses and utilizing a lesser researched variant of the root that is commonly sold as a dietary supplement.Echinacea should not be used by persons with progressive systemic and auto-immune disorders such as tuberculosis, leicosis, connective tissue disorders, collagenosis, and related diseases such as lupus erythematosus, according to the German Kommission E. Its use in AIDS or against opportunistic infections in AIDS patients is controversial. If used for more than 8 weeks, Echinacea may cause liver damage (Miller, 1998). It should not be used with other known hepatotoxic drugs such as anabolic steroids, amiodarone (Pacerone^® or Cordarone^®), methotrexate, or ketoconazole (Nizoral^®).

References

• Miller, Lucinda G. 1998. "Herbal medicines. Selected clinical considerations focusing on known or potential drug-herb interactions". Arcives of Internal Medicine, 158: 2200-2211.November 9, 1998
• Taylor, J. A., et al. 2003. "Efficacy and safety of echinacea in treating upper respiratory tract infections in children: a randomized controlled trial." Journal of the American Medical Association. December 3, 2003
• Turner, R. B. et al. 2005. An evaluation of Echinaceae angustifolia in experimental rhinovirus infections. The New England Journal of Medicine, 353: 341-348. July 28, 2005