A COMMONLY used herbal supplement could be causing birth defects, say
researchers who have discovered high levels of the toxin colchicine in one brand
of a supplement often used by pregnant women.
During routine tests of placental blood taken from 24 pregnant women, Howard
Petty and his colleagues at Wayne State University, Detroit, were surprised to
find colchicine in five of them. The levels were high enough to have harmful
effects and were 鈥渆ntirely unanticipated鈥�, they say.
Colchicine is found naturally in many plants. It is sometimes used to treat
gout, but it interferes with cell division and can be fatal at high doses. At
lower levels, it is known to damage fetuses.
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Petty and his team were puzzled where the colchicine in the blood samples had
come from, until they realised that the women with the chemical in their blood
had all been taking herbal supplements.
When the researchers tested a popular herbal supplement containing ginkgo
biloba bought at a local pharmacy they found that it contained colchicine.
Ginkgo biloba, extracted from the maidenhair tree, is normally used to treat
Alzheimer鈥檚 and memory loss in older people. But it has recently become popular
among young people who hope it will enhance memory.
The researchers only tested one sample of ginkgo biloba, although they
haven鈥檛 said which brand. 鈥淚t would be premature to generalise this to all
manufacturers,鈥� says Petty. But he warns that the problem could apply to other
herbal medicines.
鈥淪uch supplements should be avoided by women who are pregnant or trying to
conceive,鈥� the researchers report in a future issue of Chemical Research in
Toxicology. 鈥淚t should never be assumed that because a therapy is
鈥榯raditional鈥� or 鈥榥atural鈥� it must be safe,鈥� adds a spokeswoman for Britain鈥檚
Royal College of Midwives.
Many herbal medicines are unregulated, so it鈥檚 impossible for consumers to
tell if they contain harmful chemicals. They tend to contain 鈥渁 whole package of
active ingredients鈥�, says John Henry, a toxicologist at St Mary鈥檚 Hospital in
London.