Potentially toxic ingredients in Chinese therapy

NEW DNA sequencing technology has revealed traces of endangered animals, potentially toxic plant ingredients and allergens in traditional Chinese medicines (TCMs) seized by Australian Customs.

Murdoch University researchers used deep sequencing to reveal the animal and plant composition of 15 TCM powders, tablets, capsules, bile flakes and herbal teas.

Researcher Dr Michael Bunce said: “Consumers should be aware of legal and health safety issues before adopting TCM as a treatment option.

“It’s hoped this new approach to genetically audit medicinal products will bring about a new level of regulation to the area of complementary and alternative medicine, and help prosecute those who seek to profit from the illegal trade in animal products.” 

Of 68 plant families identified, four samples (including laryngitis pills) contained DNA similar to ephedra, a poisonous herb whose products are banned in the US, and/or asarum. Compounds from both can be potentially toxic in high doses but no concentration was listed.

Multiple samples contained DNA from animals listed as trade-restricted under the Convention on International Trade in Endangered Species.

DNA found included vulnerable or endangered species such as the Asiatic black bear and saiga antelope.

Ingredients were commonly undeclared or mislabelled, including failure to declare potential allergens such as nuts. 

Other product labels did not reveal that the contents included goat, sheep, deer or cow DNA.

PLoS Genetics 2012; online 12 April