News Release

Chemical found in herbal medicine might complicate pregnancy

Peer-Reviewed Publication

American Chemical Society

Researchers have found the potentially harmful compound colchicine in the placental blood of women taking the popular herbal medicine Gingko biloba. Previous research has indicated that colchicine can harm a woman’s developing fetus.

The finding will be published in the September issue of Chemical Research in Toxicology, a peer-reviewed journal of the American Chemical Society, the world’s largest scientific society.

The researchers believe the colchicine might have come from commercially available Gingko biloba (gingko) supplements taken by some of the women in their study, according to Shahriar Mobashery and Howard Petty, who led the research team at Wayne State University in Detroit. Colchicine, an alkaloid, has beneficial effects as an anti-inflammatory drug that can prevent cell growth. But at high doses it can be fatal, the researchers warn. The substance, not normally found in humans, is present in nearly 200 species of plants.

The report is the first finding of colchicine’s presence in blood from a human placenta, the sac that lines the mother’s womb and partially envelops the fetus. The researchers caution that they have no evidence that gingko taken during pregnancy causes birth defects, suggesting only that the potential for problems exists and that expectant mothers should avoid taking the substance as they should avoid other risks, like smoking or drinking alcohol.

“If you’re pregnant or planning on getting pregnant, you probably should think about this before you take gingko,” Petty said. “During pregnancy, both the woman and the fetus are vulnerable, so extra caution should be observed.”

Petty suggested the situation may be analogous to a pregnant woman’s drinking coffee: while the caffeine from a cup of coffee is quickly cleared from the mother’s system, it can build up in the womb. Mobashery added that further study would be needed to prove a correlation between gingko and complications during a pregnancy.

Their study used placental blood samples taken from 24 new mothers in the Detroit area. Measurements confirmed that the five women who regularly took gingko had colchicine levels ranging from 49 to 763 micrograms per liter of blood, while the remaining 19, which included a few vegetarians, had less than two micrograms of colchicine in their placental blood, Petty said.

The average colchicine content was approximately 26 micrograms per tablet of store-bought Gingko biloba, although the researchers declined to say which company’s brand was measured. Herbal medicines are treated as food items by the U.S. Food and Drug Administration and therefore not analyzed as drugs.

Because different companies use different components in their supplements, a comprehensive follow-up study would be necessary to pinpoint the source of the colchicine and help determine whether there should be any regulation or warnings for pregnant women, Petty said.

“The thing is, if you know colchicine is there, you’re not going to take it,” Petty concluded. “But if you don’t know it’s in these herbal medicines, suddenly you’re exposed to it and you could have some problems. It’s not that herbal medicines are bad, it’s just that you have to know what you’re taking.”


— By Jonathan Lifland

The online version of the research paper cited above was initially published August 4 on the journal’s Web site. Journalists can arrange access to this site by sending an email to or calling the contact person for this release.

A feature story about this research appeared in the August 13 issue of Chemical & Engineering News, the weekly newsmagazine of the American Chemical Society.

Shahriar Mobashery, Ph.D., is director of the Institute for Drug Design and a professor in the Department of Chemistry at Wayne State University in Detroit, Mich.

Howard R. Petty, Ph.D., is a professor in the Department of Biological Sciences at Wayne State University in Detroit, Mich.

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