International researchers look more closely at the popular plant
Don’t take your echinacea for granted—at least that seems to be the message of an international forum held in Kansas City, Missouri, last June. As scientists conduct more research, new uses and standards for echinacea are coming to the forefront, including discussions on the best way to standardize products and echinacea’s success in treating radiation exposure. Here are some highlights from the symposium.
American companies are making a mistake when they standardize echinacea products to a single active chemical component or fraction, said leading echinacea researcher Rudolf Bauer, Ph.D., professor of pharmaceutical biology at Heinrich Heine University in Düsseldorf, Germany. According to Bauer, who has researched echinacea chemistry and pharmacology for fifteen years, the quality standard for echinacea preparations in Europe is based on the composition of the entire extract, not on a single chemical compound. Many manufacturers in the United States standardize to total phenolic compounds.
“Measuring the quality of an echinacea preparation based on total phenolic compounds is like judging the quality of an automobile based on its iron content,” Bauer said. Depending on a “standardized” chemical isn’t scientifically meaningful and only serves to confuse consumers, he added. Bauer and other researchers emphasized that no one chemical or chemical group has been found solely responsible for the herb’s ability to stimulate the immune system.
Following the Chernobyl disaster in 1984, echinacea became the subject of intensive research in the Ukraine in a search for immunostimulants. Ukrainian researchers have found that echinacea may help the body cope with radiation exposure, said Victoriya Pochernyayeva from the Department of Clinical Pharmacology at the Ukrainian Medical and Dental Academy.
Since the late 1980s, Ukrainian scientists have showed that Echinacea purpurea—used as an additive in fruit juice as well as in nonalcoholic and alcoholic beverages—has had a protective effect on some of the thousands of Ukrainians exposed to radiation after the Chernobyl incident. Echinacea extracts have an antioxidant effect against free-radical damage to tissues caused by radiation. Echinacea also has helped to protect the male reproductive system against radiation damage.
New Research Designs
Bruce Barrett, M.D., of the University of Wisconsin, spoke on the design of echinacea clinical studies. His research group has recruited volunteers from the university’s student population to participate in a clinical study to evaluate the effects of echinacea extract or placebo on the severity and duration of upper respiratory tract infections. Participants are required to report to a website on a daily basis to monitor their medical assessment. Results of the study have yet to be published.
“Measuring the quality of an echinacea preparation based on total phenolic compounds is like judging the quality of an automobile based on its iron content.”
—Echinacea researcher Rudolf Bauer
The 1999 International Echinacea Symposium was sponsored by the American Herbal Products Association. About 200 participants attended including leading echinacea researchers from the United States, Germany, Switzerland, and the Ukraine. Copies of the proceedings are available from the American Herbal Products Association, 8484 Georgia Ave., Suite 370, Silver Spring, MD 20910; (301) 588-1171. Cost is $175 plus $5 shipping and handling.
Manufacturers generally standardize echinacea products to one of three compounds: echinacoside, phenolic acids, or alkylamides.
Echinacoside was the first compound to which biological activity was attributed, based on a study published in 1950 that found it had mild antibacterial activity. For nearly two decades, it was the only isolated compound from an echinacea species to which activity was attributed. Once thought to be found only in E. angustifolia, we now know that at least five echinacea species contain the compound.
It’s not found, however, in the commonly used E. purpurea. When products using that species came on the market, manufacturers attempted to mirror the “standard” for E. angustifolia. Echinacoside is part of a larger group of compounds, called phenols, so manufacturers standardized products to total phenolic compounds.
Here’s the catch—phenols are a broad group of compounds, and measuring them is comparable to measuring the total proteins in a steak. Because the group is so broad, it may include any number of compounds, not all of which will necessarily have medicinal value.
A third category of compounds, called alkylamides, are also used for standardization. These are the compounds that produce a numbing sensation when you squirt some echinacea tincture on your tongue. When used as isolated compounds in research studies, some alkylamides have shown immunostimulatory activity.
This doesn’t mean that any single echinacea product should be avoided. It does mean, however, that there’s no definitive chemical standard for echinacea—it’s still a matter of guesswork, not guarantees. That’s why the whole plant or plant part is still the best “standard.”
For further information see Echinacea: Nature’s Immune Enhancer by Steven Foster (Healing Arts, 1991).x
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