Globally, there has been an increase in the use of herbal remedies including traditional Chinese medicine (TCM). There is a perception that products are natural, safe and effectively regulated, however, regulatory agencies are hampered by a lack of a toolkit to audit ingredient lists, adulterants and constituent active compounds.
A new study just published in Nature Scientific Reports does just that (including metabarcoding) and the results are - perhaps not surprising - pretty alarming. Researchers of Curtin University, Murdoch University and the University of Adelaide found that 90 % of 26 widely available medicines (in Australia) tested were not fit for human consumption. Half contained illegal substances, including toxic metals, prescription medications, stimulants and animal DNA, none of which were listed on the product's label.
Arsenic, cadmium and lead were found in some of the Chinese medicine. One of the herbal concoctions contained over 10 times the recommended daily limit for arsenic exposure. Another contained strychnine, which is used as a rat poison and at lower levels as a performance-enhancing drug. The researchers also found one of the herbal medicines for sale had trace amounts of snow leopard DNA in it. In addition they found DNA from pit vipers, frogs and trace amounts of cat and dog DNA. Whether the animal products were primary ingredients or the result of a poor manufacturing processes is yet to be determined.
The researchers were especially concerned about contamination with undisclosed pharmaceuticals. Over-the-counter drugs like paracetamol and ibuprofen were found but also steroids, blood thinner warfarin and even sildenafil, the active ingredient in Viagra.
Here the summary of the paper:
This study presents genetic, toxicological, and heavy metal data that should be of serious concern to regulatory agencies, medical professionals and the public who choose to adopt TCM as a treatment option. Of the 26 TCMs investigated, all but two can be classified as non-compliant on the grounds of DNA, toxicology and heavy metals, or a combination thereof. In total, 92% were deemed non-compliant with some medicines posing a serious health risk. The multi-tiered approach outlined in this study provides a much-needed auditing toolkit that should swiftly form the basis of best-practice pharmacovigilance across the CAM [complementary and alternative medicines] sector.