Australian ‘toxic’ traditional Chinese medicine curbed with DNA testing, say researchers

Scientific researchers from the University of Murdoch in Perth conducted DNA sequencing tests on 15 samples of TCMs seized at Australia’s border control.

Findings showed some to be mislabelled, containing potentially toxic ingredients, allergens and traces of endangered animal species.

Included among the samples tested were Kai Yeung pills, Ling Yang Ge Gen cold remedy, Laryngitis pills A and B and Saiga Antelope Horn powder. The study, published in the journal of PLoS Genetics is [available here]​.

Dr Mike Bunce, research leader and future fellow at Murdoch University, championed the use of genetic auditing in the complementary and alternative medicines (CAMs) sector to quantify ingredients lists and detect toxic properties.

“Over the next few years I think that DNA audits of herbal CAM products, both pre and post-market, will become the best practice for regulatory agencies,”​ Bunce told FoodNavigator-Asia.

“Such a system can only bring increased fidelity to the sector,”​ he added.

Regulations suffice? Simply ‘rogue’ samples?​

But the Complementary Healthcare Council of Australia (CHC) said in a statement that regulation is currently sufficient and the study validates the country’s, “tight regulatory regime around therapeutic goods; widely regarded as a global benchmark,”​ as the products were seized by Australian Border Officials.

Dr Wendy Morrow, executive director of CHC, said that the samples tested in this study were “rogue”​ products and that the research should not “tarnish an entire industry”.​

“It is important to understand that these study findings are not representative of products imported legally,”​ Morrow said.

However, Bunce said that “there is little evidence on the degree of non-compliance in this sector,”​ and suggested that “it would be naïve to think that border protection is full-proof.” ​Controls could be better he said, but this could cost large sums of money.

Morrow did acknowledge that care should be taken when purchasing complementary medicines online as the products bypass Australian standard checks.

Toxic, endangered ingredients​

Findings showed a product labelled 100% Saiga antelope to contain ‘considerable quantities’ of goat and sheep DNA.

Another product, Mongnan Tianbao pills, was found to contain deer and cow DNA without labelling; “the latter of which may violate religious or cultural strictures,” ​Bunce said.

Some of the TCM samples contained the plant extracts Ephedra and Asarum that can be toxic if taken in the wrong dosage, without listed concentrations on the packaging.

Traces of trade restricted animals classified as vulnerable, endangered or critically endangered were also identified in samples, including the Asiatic black bear.

The intricate potential of DNA auditing…​

The study “demonstrates that deep sequencing via high-throughput sequencing (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."​

Bunce explained that initially, implementing equipment for such testing can be costly but that in the long-run it can be very cost-effective due to the amount and quality of DNA data obtained.

“The biological origin of ingredients within each remedy to be reliably determined,”​ they wrote, due to the complex list of ingredients and heterogeneous origins as well as subsequent processing into pills and powders.

Megan Coghlan, a PhD student of DNA techniques in wildlife forensics, said, “the approach has the ability to unravel complex mixtures of plant and animal products.”​

Bruce said that, “auditing TCMs would assist in prosecuting individuals who seek to profit from the illegal trade in animal products,”​ and should the testing become widespread, it could drive a new level of regulation within the CAMs sector in Australia.

Bunce and his team have applied to the Australian National Health and Medicinal Research Council (NHMRC) for funding to expand testing and are set to hear back towards the end of 2012. “We are continuing to do the work on a shoe-string budget until then,”​ he said.