Traditional Chinese Medicines Could Be Dangerous

A study that analyzed samples of traditional Chinese medicines (TCMs) using DNA sequencing technology revealed that some contained potentially toxic plant ingredients, allergens, and traces of endangered animals.

Researchers at Murdoch University (Perth, Australia) analyzed TCM’s seized by the Australian Customs and Border Protection Service, and the International Wildlife Trade Section; the 15 TCM samples came in powder form, tablets, capsules, flakes, and herbal teas. Using second-generation, high-throughput sequencing (HTS) of DNA, the researchers genetically audited organic ingredients within complex TCMs. Comparison of DNA sequence data to reference databases revealed the presence of 68 different plant families and included genera, such as Ephedra and Asarum, that are potentially toxic if the wrong dosage is taken, but none of them actually listed concentrations on the packaging.


The researchers also found traces from trade restricted animals that are classified as vulnerable, endangered, or critically endangered, including the Asian black bear (Ursus thibetanus) and Saiga antelope (Saiga tatarica). Another aspect of TCMs is product mislabeling. Consumers are not aware that the products contain hazardous ingredients, such as animal DNA and potential allergens like soy or nuts. For example, a product labeled as 100% Saiga antelope was found to contain considerable quantities of goat and sheep DNA. Another product, Mongnan Tianbao pills, contained deer and cow DNA, which could also violate some religious or cultural strictures. The study was published in the April 2012 issue of PLoS Genetics.

“This study demonstrates that deep sequencing via HTS is an efficient and cost-effective way to audit highly processed TCM products and will assist in monitoring their legality and safety, especially when plant reference databases become better established,” concluded lead author Michael Bunce, PhD. “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. Auditing TCMs would assist in prosecuting individuals who seek to profit from the illegal trade in animal products.”

TCM has been practiced for thousands of years, but only within the last few decades has its use become more widespread outside of Asia. Concerns continue to be raised about the efficacy, legality, and safety of many popular complementary alternative medicines, including TCMs, ingredients of which are known to include derivatives of endangered, trade-restricted species of plants and animals, and therefore contravene the Convention on International Trade in Endangered Species (CITES) legislation.

Chromatographic studies have also detected the presence of heavy metals and plant toxins within some TCMs, and there are numerous cases of adverse reactions.

As of July 2012, all TCM practitioners in Australia must register with the new national Chinese Medicine Board of Australia, which will become part of the Australian Health Practitioner Regulation Agency (Canberra).

Related Links:
Murdoch University
Australian Health Practitioner Regulation Agency