Endangered Animals, Toxins, and Heavy Metals Found in Chinese Medicines

DNA tests reveal 'natural' remedies are anything but.
(Photo: Danita Delimont/Getty Images)
Apr 18, 2012
Megan Bedard is a sucker for sustainable agriculture and a good farmers market, she likes writing about food almost as much as eating it.

Hundreds of millions of dollars are spent on traditional Chinese medicine (TCM) every year. Few Eastern medicine enthusiasts probably know, however, that the concoctions they're buying may contain toxins, carcinogens, and critically endangered animals.

A recent study by researchers at Murdoch University in Australia investigated medicine seized at the Australian border and revealed some scary results: Of the 15 medicines they examined, some failed to list ingredients entirely, while others listed illegal or carcinogenic ingredients.

After smashing up the samples, the researchers "fished out copies of two specific genes, tmL, a chloroplast gene common to all plants, and 16srRNA, conserved among plants and animals, and multiplied and sequenced them," Science Now reports. With the genetic databases, they were able to suss out the specifics of the medicine's ingredients.

The team, based at Murdoch University's Australian Wildlife Forensic Services and Ancient DNA Laboratory in Perth, says that although this type of investigation has been difficult previously due to medicine's "heterogeneous origins, and subsequent processing into pills and powders," this particular study was different.

"In this study, we have, for the first time, used a second-generation DNA sequencing method to analyse TCM remedies and determine their animal and plant composition," states the report, which was published by the Public Library of Science.

In some cases, there was no attempt to disguise or hide information; labels simply stated that critically endangered animals, including the Asiatic black bear, the Saiga antelope, and rhinocerous, were ingredients in the medicines. In other cases, the labeling was misleading. One of the researchers, molecular geneticist Michael Bunce, said that a product labeled "100 percent Saiga antelope" actually contained significant amounts of goat and sheep DNA.

According to the report, "in 78 percent of samples, animal DNA was identified that had not been clearly labelled on the packaging (in either English or Chinese)." Such a discovery is a breakthrough, because it makes tracking illegal animal trading easier.

The pills and powders aren't just dangerous to animals, though; they're also potentially hazardous to the humans who seek them out.

Among the herbal preparations, the team found members of 68 different plant families, among them two plant types (Ephedra and Asarum) that contain toxic chemicals, including aristolochic acid. Aristolochic acid is a compound banned in many countries because it is known to cause kidney disease and cancer of the upper urinary tract. Though the presence of the plants' DNA does not guarantee the presence of aristolochic acid, the researchers did find aristolochic acid in one of the four Asarum samples.

Previous studies have found that Taiwan has the highest rate of upper urinary tract cancer, and one-third of its population consumes herbs that are likely to contain aristolochic acid.

The researchers recommend more widespread testing, saying that the growing popularity of the medicine presented an urgency.

"...[W]e identified plant species that are known to contain toxic chemicals and identified animal DNA from species that are currently endangered and protected by international laws," the reports states. "Consumers need to be made aware of legal and health safety issues that surround TCMs before adopting them as a treatment option."

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