New support for echinacea's benefits

Science News, March 27, 1999 by J.R.

In last year's movie Celebrity, Woody Allen satirized echinacea's trendy status by showing a panicked supermodel who, feeling the first hints of a cold coming on, demanded a middle-of-the-night search for the herbal remedy. She shouldn't have had to look far. Today, even many supermarkets carry this botanical derived from the purple coneflower (Echinacea purpurea). Less easy to find have been scientific studies that back up echinacea's reputed infection-fighting powers.

Now, a nutritionist at the University of Florida in Gainesville has preliminary data to suggest that anecdotal claims for this herbal remedy, hold merit.

Susan Percival administered a commercial over-the-counter echinacea supplement to 10 male college students for 4 days. According to the label, each pill contained 150 milligrams of active ingredients, known as echinosides. On the first and last day of treatment, Percival drew blood from the volunteers and separated out the neutrophils, a type of white blood cell. These cells respond to infectious agents by generating superoxide anion, a highly reactive and biologically damaging oxidant.

Percival stimulated the students' cells using a technique that mimics an encounter with germs. Neutrophils collected after the echinacea treatment produced triple the amount of superoxide anion as did those gathered at the start of the test. Percival plans to report her new data next month at the Experimental Biology meeting in Washington, D.C.

"Our studies so far have shown only that we could enhance certain functions of the immune system," she notes. Echinacea might suppress other, as yet unexamined aspects, she adds. At a minimum, she argues, "it's very important that we find out exactly what the active compounds are," how they work, and their optimal doses.

Her current findings argue against taking the supplement on a regular basis, she says, because "a stimulated immune system produces a lot of [oxidizing] free radicals," which can damage healthy tissue. This therapy "is meant to treat something," she stresses, "not to prevent disease."