'Standardization' May Not Indicate Echinacea Quality

'Standardization' May Not Indicate Echinacea Quality

DENVER--A label claiming"standardization" does not guarantee a preparation is accuratelylabeled, nor does it indicate less variability in concentration of herbalconstituents--at least in the case of echinacea, according to researchers fromthe University of Colorado Health Sciences Center. Researchers--who publishedtheir work in the March 24 issue of the Archives of Internal Medicine (163,6:699-704, 2003) (http://archinte.ama-assn.org)--undertookthe study because "there is no guarantee as to the content, quality,variability or contamination in the various preparations" of echinacea, anherb that represents 10 percent of the U.S. dietary supplement market.

To test echinacea preparations for accuracy of species labelingand to compare actual constituent content with labeling claims, researchers usedthin-layer chromatography (TLC). They purchased 59 single-herb echinaceapreparations from Denver-area stores and determined nearly 10 percent (sixproducts) contained no measurable echinacea at all, and only half of the samples(31 products) contained species consistent with label claims. Researchers alsonoted that of 21 standardized preparations, nine met the quality standarddescribed on the label.

According to Mark Blumenthal, executive director of the AmericanBotanical Council, there were several limitations of the study. "The firstweakness of this particular study is the testing was done using TLC," hesaid. "TLC gives you a 'color fingerprint' of some of the compounds thatbasically works to identify certain compounds, but it's a qualitativeassessment, not a quantitative measure."

Some other limitations Blumenthal noted were that none of theauthors of the study appeared to be analytical chemists, and the laboratory theycontracted was not well-known for botanical testing. In addition, Blumenthalcommented that the results were not clearly presented, with much of the databeing "averaged in."

"Based on my knowledge of this industry, with 59 products,I would have expected 90-percent or more of those products to contain echinacea,"Blumenthal said. "The results of the study and the conclusions being drawndon't reflect the realities of the marketplace."