Ginkgo Herbal Supplements Vary Widely In Content
   
  By the American Chemical Society


New faster analytical technique could help address quality control issues

Consumers of Ginkgo biloba herbal products, offered in alternative medicine circles as a remedy for just about everything from dementia to impotence, may not be getting their money's worth, according to a new study by scientists at the University of Idaho. Using a new analytical chemistry technique they developed specifically to examine Ginkgo samples, the researchers found variations of up to tenfold in the Ginkgo products they tested.

"Consumers seldom can be sure exactly what they are buying," says chemistry professor Chen Wai, Ph.D., lead researcher for the study, which will appear in the July 15 print issue of the peer-reviewed science journal Analytical Chemistry, published by the American Chemical Society, the world's largest scientific society. The report initially was published on the journal's Web site on May 29.

"The large variation of active ingredients found in Ginkgo biloba products could be a problem for the consumers," the researchers write in the journal article.

Ginkgo products are based on herbal extracts from the leaves of the Ginkgo biloba tree, also known as the maidenhair tree, which first appeared on Earth during the time of the dinosaurs about 200 million years ago. Widely marketed as a way of improving mental alertness and slowing the development of Alzheimer's disease, Ginkgo supplements are among the top selling herbal products in both Europe and the U.S. and have long been a staple of Chinese herbalists.

Chemical substances known as ginkgolides and bilobalide, found in the leaves of the tree, are believed to be the most pharmacologically active compounds, say the researchers. However, they point out, as is the case with many herbal products, the active ingredients are usually present in only trace amounts along with large quantities of other compounds. Determining the amount of ginkgolides and bilobalide in Ginkgo products generally is a time-consuming and tedious process, which has added to the difficulty of establishing efficient quality control programs for the products, claim the researchers.

"The lack of simple and reliable separation and analytical processes for herbal products is probably a major cause of the quality-related problems found in the herbal medicine market today," according to the researchers.

The process developed by Wai and colleague Qingyong Lang could help solve that problem by reducing the time required to separate the active ingredients from hours to just a few minutes. It essentially involves boiling the leaves of the tree, or Ginkgo extract products, to separate the ginkgolides and bilobalide and then using a common analytical instrument called a gas chromatograph to measure the compounds.

"Compared to other reported methods for ginkgolide separation, this method can significantly reduce the operation time," say the researchers. "The principle of this analytical method may also be applied to other medicinal herbs," they add.

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A nonprofit organization with a membership of nearly 159,000 chemists and Chemical engineers as its members, the American Chemical Society publishes scientific journals and databases, convenes major research conferences, and provides educational, science policy and career programs in chemistry. Its main offices are in Washington, D.C., and Columbus, Ohio. http://www.acs.org

Note: This story has been adapted from a news release issued by American Chemical Society for journalists and other members of the public. If you wish to quote from any part of this story, please credit American Chemical Society as the original source. You may also wish to include the following link in any citation: http://www.sciencedaily.com/releases/1999/06/990621043118.htm





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