April 14, 2012
DNA Sequence Finds Endangered Animals In Traditional Chinese Medicines
Researchers at Murdoch University have revealed the composition of traditional Chinese medicines (TCM) through DNA sequencing technology.
They found that some of the 15 TCM samples tested contained potentially toxic plant ingredients, allergens, and 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," Dr Bunce, research leader and Murdoch University Australian Research Council Future Fellow, said in a press release.
The samples of the medicine were seized by Australian border officials in the form of powders, tablets, capsules, flakes, and herbal teas.
The team said they found 68 different plant families in the medicines, some of which contained plants of the genus Ephedra and Asarum.
"These plants contain chemicals that can be toxic if the wrong dosage is taken, but none of them actually listed concentrations on the packaging," Bunce said. "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."
DNA sequencing has made it possible to determine the biological origins of ingredients contained within TCMs because processing into pills and powders makes identification difficult.
"The approach has the ability to unravel complex mixtures of plant and animal products," PhD student Megan Coghlan, who is studying the application of DNA techniques in wildlife forensic applications, said.
She said that research shows that second-generation, high throughput sequencing is an efficient and cost-effective way to audit the species composition.
The TCMs industry has increased to hundreds of millions of dollars per year, putting a strain on the endangered animals found in the medicines.
"We found multiple samples that contained DNA from animals listed as trade-restricted according to the Convention on International Trade in Endangered Species Legislation. Put simply, these TCMs are not legal," Coghlan wrote.
Consumers are not aware of the presence of the endangered species, or the toxic plants, because of the mislabeling of TCMs.
"A product labeled as 100 per cent 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 some religious or cultural strictures."
He said he hopes the new approach to genetically audit medicinal products will help bring a new level of regulation to the traditional Chinese medicines.
"Auditing TCMs would assist in prosecuting individuals who seek to profit from the illegal trade in animal products," Bruce said in a statement.
Bruce said he and his team plan to expand the use of these new DNA tests to evaluate other herbal medicines.
The results of the DNA sequencing were published in the journal PLoS Genetics.