A few weeks ago, as I flipped through a copy of USA Today while flying home from New York, I was surprised to discover a full-page ad for an echinacea product. When a reporter from the National Public Radio science desk called the same week looking for information on echinacea as a dietary supplement, I knew that echinacea had come of age as a popular medicinal herb.
Echinacea has become the decade’s best-selling herb in U.S. health-food stores.
Once an obscure plant whose name few could pronounce, echinacea has become the decade’s best-selling herb in U.S. health-food stores. By stimulating the body’s immune system to work more effectively, echinacea wards off colds and flu if taken when symptoms first appear and speeds healing of existing infections.
Echinacea is not just one plant but a genus of nine species native to central North America. Three species, Echinacea purpurea, E. angustifolia, and (to a lesser extent) E. pallida, are used in commercial herb products.
• E. purpurea , a favorite garden perennial with its brilliant late-summer display of large purple daisies on 3- to 4-foot stalks, was introduced into English gardens as early as 1699 and has been under cultivation ever since. Unlike the other echinaceas, this species has a fibrous root instead of a taproot. The leaves are oval, tapering to a sharp point, with irregular teeth. It is the most widespread species of echinacea in North America, although not the most abundant, occurring in moist soils in woods, at edges of thickets and prairies, and near springs, often as a solitary plant or in small populations.
• E. angustifolia was the first species of echinacea to be marketed as a medicinal product (in 1895). The herb contains compounds that produce a numbing sensation on the tongue, which some herbalists view as evidence of its medicinal superiority over the other species. Smaller than other echinacea species, growing from 6 to 20 inches high with ray flowers no longer than 1 1/2 inches, it occurs in dry prairies and barrens in the western parts of Oklahoma, Kansas, Nebraska, and Iowa north to Canada and west to eastern Colorado and Montana; the graves of Custer’s soldiers at Little Bighorn are dotted with these colorful plants.
Most of the commercial supply of E. angustifolia is still harvested from the wild, raising concerns that populations may be depleted or destroyed as its popularity grows. However, large-scale commercial cultivation has begun in a number of prairie states, as well as in Washington and the province of Ontario in an effort to meet the growing demand.
• E. pallida is like a large version of E. angustifolia., standing 16 to 36 inches tall with long, slender, entire leaves. Its drooping ray flowers (“petals”) may be as long as 5 inches. E. pallida occurs in glades, prairies, fields, rock outcrops, and roadsides from northeastern Texas, eastern Oklahoma, and Kansas north to Iowa and Wisconsin and east to Indiana. Most interest in this species as a source of medicine comes from Europe.
As to which of the three species is most effective in stimulating the immune system, I believe that high-quality preparations of all three are probably equally good. E. purpurea has been the most researched species while E. angustifolia has the best-documented history of clinical use.
Until the 1930s, most echinacea products were made from E. angustifolia—or E. pallida mistakenly gathered as E. angustifolia. Supply shortages late in the decade brought a leading German manufacturer of echinacea products to the United States in search of seeds. He bought what he thought were E. angustifolia seeds from a Chicago seed company, but the resulting plants turned out to be E. purpurea. He eventually made products from them anyway. As a result, most of the scientific research conducted on echinacea in Europe since then has involved products made with E. purpurea.
Although echinacea products sold in the United States must be labeled as dietary supplements, in Germany they have long been sold over the counter as nonspecific immune-system stimulants. The more than 300 echinacea products available in Germany come in tablet, capsule, extract, tincture, salve, and ointment form as well as injectable echinacea for use by physicians to treat more serious ailments. German pediatricians are so convinced of echinacea’s effectiveness that they recommend it almost daily.
No single chemical has been found responsible for echinacea’s ability to stimulate the immune system; in fact, whole-plant extracts seem to be more effective than those containing an isolated compound. Certain polysaccharides, flavonoids, essential oils, caffeic acid derivatives, isobutylamides, and cichoric acid all may play a role in producing echinacea’s effects.
Extracts from both the root and the flowering tops increase the number of white blood cells and activate macrophages, specialized cells that patrol the bloodstream in search of invading viruses, bacteria, or other foreign particles to ingest. Echinacea extracts also increase levels of properdin, a protein that battles bacteria and viruses.
Echinaceas thrive in full sun or part shade and moist soil in Zones 3 through 9. Plants live for many years with little care. You don’t have to destroy them to harvest them for medicinal use.
I make a tea with the flowering tops of E. purpurea. Simply pluck a flower, chop it finely, and place the pieces in a tea bag or nonreactive strainer. Pour water over the mass and steep, covered, for 15 minutes. To dry the flower heads for later use, lay them on a screen or tray and place it in a dark place with good air circulation.
Two double-blind, placebo-controlled clinical studies, both conducted in Germany in 1992, support the use of echinacea products to fight colds and flu. In one, involving 180 participants, those receiving the equivalent of 900 mg per day of the dried root of E. purpurea for 10 days fared significantly better than those receiving either half that dose or a placebo.
The other study evaluated the severity of colds and flu symptoms in 108 individuals with compromised immune systems (as shown by abnormally low blood T-cell ratios). Those in the treatment group, who had received 2 to 4 ml per day of the expressed fresh juice of E. purpurea tops for eight weeks, had fewer and briefer infections with milder symptoms than those receiving a placebo.
A recent review of twenty-six controlled clinical studies of echinacea found that twenty involved herbs such as wild indigo (Baptisia tinctoria) and white cedar (Thuja occidentalis) in addition to echinacea. Only six studies evaluated echinacea alone, either as the root (E. angustifolia and E. purpurea) or juice from the flowering tops (E. purpurea). The authors concluded that although echinacea seems to be an effective immunostimulant, more and better-designed studies are needed to identify the most effective part(s) to use as well as optimal methods of preparation and appropriate dosage.
The governmental agency responsible for regulating herb use in Germany, Commission E, cautions that people with diabetes mellitus, multiple sclerosis, lupus erythematosus, acquired immune deficiency syndrome (AIDS), and other diseases of the immune system refrain from taking echinacea. People who are allergic to ragweed or other members of the aster family (Compositae) may also be allergic to echinacea and thus should avoid it.
• Bräunig, B., et. al. “Echinacea purpurea Radix for Strengthening the Immune Response in Flu-like Infections”. Zeitschrift für Phytotherapie 1992, 13:7–13.
• Foster, S. Echinacea: Nature’s Immune Enhancer. Rochester, Vermont: Healing Arts Press, 1991.
• Lloyd, J. U . “History of Echinacea angustifolia”. Pharmacognosy Review 1904, 22(1):1–14.
• ——-. A Treatise on Echinacea. Drug Treatise No. 30. Cincinnati, Ohio: Lloyd Brothers Pharmacists, 1921.
• Schöneberger, D. S., M. Klein, trans. “The Influence of Immune-Stimulating Effects of Pressed Juice from Echinacea purpurea on the Course and Severity of Colds”. Forum Immunologie 1992, 8:2–12.
• Tyler, V. E. Herbs of Choice: The Therapeutic Use of Phytomedicinals. Binghamton, New York: Pharmaceutical Products Press, 1994.
• Wagner, H., and A. Proksch. “Immunostimulatory Drugs from Fungi and Higher Plants”. In Economic and Medicinal Plant Research, edited by H. Wagner, H. Hikino, and N. R. Farnsworth, 1:113–155. Orlando, Florida: Academic Press, 1985.