USA - Traditional Medicines Found To Contain Toxins And Illegal Ingredients

Researchers have discovered that some traditional Chinese medicines contain potentially toxic plant ingredients, allergens, and even traces of endangered animals.

Researchers at Murdoch University have used new DNA sequencing technology to study the animal and plant composition of traditional Chinese medicines (TCM) – with worrying results.

The results, published in the journal PLoS Genetics, revealed that some TCMs contained potentially toxic plant ingredients, allergens and even traces of endangered animals.

“TCMs have a long cultural history but today, consumers need to be aware of the legal and health safety issues before adopting them as a treatment option,” said research leader and Murdoch University Australian Research Council Future Fellow, Dr. Mike Bunce.

Fifteen TCM samples, seized by border officials, in the form of powders, tablets, capsules, flakes and herbal teas were audited using the DNA preserved in the samples. In total, the researchers found 68 different plant families in the medicines, representing complex mixtures of species.

“Some of the TCMs contained plants of the genus Ephedra and Asarum. These plants contain chemicals which can be toxic if the wrong dosage is taken, but none of them actually listed concentrations on the packaging,” said Bunce.

“We also found traces from trade restricted animals that are classified as vulnerable, endangered, or critically endangered, including the Asiatic black bear and Saiga antelope.”

Until now it has been difficult to determine the biological origins of ingredients contained within TCMs because processing into pills and powders makes identification difficult. Using second-generation, high throughput sequencing, the team was able to apply DNA techniques to audit the species composition.

Another worrying concern is the mislabeling of TCMs meaning consumers are unaware of the presence of some ingredients including animal DNA and potentially allergens such as soy or nuts.

“A product labeled as 100 percent Saiga antelope contained considerable quantities of goat and sheep DNA,” Bunce said. “Another product, Mongnan Tianbao pills, contained deer and cow DNA, the latter of which may violate religious or cultural strictures.”

Incorrect labeling makes it difficult to enforce legislation and to prosecute cases of illegal trade.

“It is hoped that this new approach to genetically audit medicinal products will bring about a new level of regulation to the area of complementary and alternative medicine,” Bunce said.

Bunce and his team have applied for funding from the Australian National Health and Medical Research Council (NHMRC) to expand the use of these new DNA tests in other wildlife forensic applications, such as to evaluate other herbal medicines.

Samantha Chan 

Health & Medicine

The article can be found at: Coghlan ML et al. (2012) Deep Sequencing of Plant and Animal DNA Contained within Traditional Chinese Medicines Reveals Legality Issues and Health Safety Concerns.

Source: Murdoch University.