Traditional Chinese medicines carry toxic compounds

Sydney, April 16 (IANS) Traditional Chinese medicines (TCMs) also carry potentially lethal plant ingredients, allergens and traces of endangered species, according to a new research, which warned the consumers to be aware of health safety issues before adopting these as a treatment option.

The 15 TCM samples, seized by Australian border officials, in the form of powders, tablets, capsules, flakes, and herbal teas were audited using the DNA sequencing technology. DNAs are preserved in the samples.

"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 Michael Bunce, research leader and Murdoch University Australian Research Council Future Fellow, the journal Public Library of Science Genetics reports.

"In total we found 68 different plant families in the medicines - they are complex mixtures of species," Bunce said.

"Some of the TCMs 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," added Bunce, according to a university statement.

Until now it has been difficult to determine the biological origins of ingredients present in TCMs because processing into pills and powders makes identification difficult.

Doctoral student Megan Coghlan, who is studying the application of DNA techniques in wildlife forensic applications, said the research shows that second-generation, high throughput sequencing is an efficient and cost-effective way to audit the species composition.

"The approach has the ability to unravel complex mixtures of plant and animal products," Coghlan said.

Further testing of TCMs would reveal the extent of the problem and make it easier for customs officials to identify the trade of endangered species. The increasing popularity of the medicines has seen the value of the industry increase to hundreds of millions of dollars per annum.

"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 said.

"A product labelled 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 some religious or cultural strictures," Bunce added.