Healthnotes Newswire — The most popular herbal supplement in America and Germany, Ginkgo biloba, is the source of controversy due to a new study published in the September issue of Chemical Research in Toxicology.¹ Scientists claimed that a toxic chemical called colchicine was identified in the placental blood of women who had taken ginkgo supplements during their pregnancy. The authors suggested that women who take ginkgo during pregnancy may be putting their fetuses at risk of abnormal development.

The goal of this study was to evaluate the effects of anti-inflammatory drugs taken by pregnant women on fetal development. Researchers collected and pooled approximately 3 liters of placental blood from 30 pregnant women after childbirth. Chemical analysis of the pooled blood revealed the presence of substantial amounts of colchicine. Individual blood samples from 24 women were then studied to see how much colchicine each placenta had retained. Five of the 24 samples contained colchicine at levels considered toxic (49 to 760 mcg/l). All five of these women reported regular herbal supplement use, while the others reported little or no use of herbs.

For reasons that are unclear, the researchers then tested commercial brands of ginkgo and echinacea for their colchicine content. Testing demonstrated that an over-the-counter ginkgo product contained significant levels of colchicine, whereas the echinacea contained little. Therefore, the authors concluded it was ginkgo that accounted for the relatively high levels of colchicine found in the placenta samples.

While claims of toxicity of herbs should be taken seriously, especially when the herbs are being taken by pregnant women, the alleged identification of colchicine in ginkgo products appears highly suspect. In over 50 years of study, no previous research team has ever identified colchicine as a regular component of ginkgo. Additionally, independent organizations that test herbal supplements for purity have failed to identify colchicine in any commercial ginkgo product. It is likely that the new report represents a case of mistaken identity. Ginkgo leaves contain a naturally occurring, nontoxic substance that is almost identical in structure to colchicine. Since the researchers did not perform the test needed to differentiate these two compounds, they cannot state with any degree of reliability that the substance they identified was, in fact, colchicine.

Colchicine occurs naturally as a component of the autumn crocus plant. It is a potent anti-inflammatory agent and has been used for many years in conventional medicine as a treatment for acute attacks of gout. An overdose of colchicine can cause serious side effects, including severe diarrhea and intestinal hemorrhage. The typical daily dose of colchicine is 600 mcg or less, which is less than the amount found in a single liter of blood taken from some of the women in this new study. Given that colchicine is incompletely absorbed, is eliminated from the body relatively quickly, and distributes in many tissues besides blood,² it seems that a person would need to take dozens, if not hundreds, of times the usual dose of colchicine in order to achieve the placental blood levels reported in this study. Such doses would almost certainly cause obvious toxic effects and might even be lethal. Since nothing remotely resembling colchicine toxicity has been reported among any of the millions of individuals who regularly take ginkgo, it is extremely unlikely that the researchers correctly identified the compound they found in this study.

Research on herbal medicines rarely looks at the effects on pregnant women, due to ethical concerns about experimenting on unborn children. As a result, little is known about the effects of many herbs on pregnant women and their fetuses. Ginkgo is no exception, as no studies have been performed evaluating the use of ginkgo during pregnancy. Despite the controversy surrounding this study, the researchers’ conclusion that ginkgo is harmful during pregnancy has yet to be substantiated. However, any woman who is pregnant should consult her healthcare provider before taking any over-the-counter supplements during pregnancy.