Many people take herbal medications, including traditional Chinese medicine( TCM) supposing they are doing something positive for their own health. Ironically, in many cases they may be doing just the opposite.
Have you ever wondered what is actually in the herbal medicine products you buy? Has the herb on the label been replaced with another herb? Have pharmaceuticals been snuck in?
Making sure that a tablet claiming to have 500 milligrams of paracetamol truly does contain 500 milligrams of paracetamol is relatively easy, there are established assays to measure paracetamol routinely. But how do you test for herbs?
Most herbal medications are pills or powders that have removed all tracing of structure we would normally use to identify plants, and many plants have no chemical signature that may be definitively identify them. And what about all the other possible contaminants and adulterants that could hide in the complex brew of chemicals from herbal medications?
For the first time, our group of researchers from Curtin University, Murdoch University and the University of Adelaide have combined some of the most cutting-edge and sensitive analytical techniques to screen a define of traditional Chinese medications available in Australia.
We employed a three-pronged approach, combining Dna sequencing, toxicology and heavy metal testing to elucidate the true composition of 26 TCMs bought at random from the Adelaide Market; most were either for colds and influenza or for general wellness.
What Did We Find ?
Summary of the contaminants in traditional Chinese medications( TCMs) tested in this study that contained toxic metals, undeclared or illegal contents as determined by DNA, toxicological, and heavy metal screening techniques. Each TCM tested is represented in the diagram as a tablet; blue shading on tablets indicate AUST L listed medications, red shade are not-listed with the TGA regulatory body. TCMs deemed non-compliant for DNA( green ), toxicology( pink) and heavy metals( yellow) or a combining thereof, are represented within the Venn diagram. Coglan et al ., Sci Reports 2015
Nearly nine in ten of these medications had some sort of undeclared substance in them as either adulteration or contamination. Sixteen of TCMs had more than one contaminant or adulterant.
While around half of these medications were not listed with the Therapeutic Goods Administration( TGA ), and should not have been available for buy, contaminants were found in both TG-Alisted and non-listed medications. These adulterants/ contaminants included pharmaceuticals and toxic heavy metals.
Plant and/ or animal Dna from species not listed on the labels were also determined. The most concerning finding was snow leopard DNA( snow leopards are an endangered species ), which was detected in one medicine. Dna from pit viper, frog, rat, cat and dog was also detected in several medicines.
Among the pharmaceuticals determined were paracetamol, antihistamines, anti-inflammatories and antibiotics, and stimulants such as pseudoephedrine. Of particular concern were medications such as warfarin, which have significant possibilities for harm if not taken under medical supervising, and ephedrine, which is banned in Australia.
Significant levels of toxic heavy metals such as arsenic, cadmium and lead discovered in over half the medications. In at the least four of these medications following the directions on the label would uncover you to over ten days the TGAs regulatory limit for heavy metals in medicines.
What Does This Mean ?
Herbal Medicines Megan Coglan
Are the levels of undeclared materials in these products adulteration or contamination? In adulteration , the material is added purposely. In contamination , the material is added unknowingly, for example, through unclean workplaces or herbs grown on polluted soil.
Whether a compound is a result of deliberate adulteration or contamination has different regulatory implications. It can entail the difference between banning a substance or cleaning up the workplace.
It can be tricky to decide which is which. In TCM materials, for instance, heavy metals or toad venom may be added as part of the therapy. However, by looking at the patterns of materials we received, we can get some hints.
One TCM claiming to enhance weight gain with appetite stimulation contained pharmaceutically relevant high levels of the narcotic cyproheptadine, a known appetite enhancer.
Intriguingly, high levels of arsenic were often determined with similar high levels of lead. Lead arsenate has been used as a pesticide, and the high levels may come from persistently polluted soils.
What this means is that you should be very careful about choosing and purchasing TCMs. Definitely avoid any medicine that does not have an ARTG listing( it should have a number like AUST L 123456 on the front of the bottle ). But even medications with these AUST L labels are no guaranty of safety.
This also highlightings the importance of informing your health practitioner if you are taking TCMs as adulterants might interact with conventional medication to cause adverse effects.
What Are The Regulatory Implications ?
Unlike countries such as the United States, where many herbal medications are regulated as dietary supplements, in Australia, herbal medications are regulated through the TGA as medicines.
TG-Aregulated medications can be approved as either registered or listed. Most herbal medications are classified as listed. Unlike registered medications such as paracetamol and warfarin, the evidence required for approval is much less stringent.
In many ways it is an honour system, where the herbal medications sponsor says theres no evidence of harm, and they hold documentation that shows this. Mostly, the evidence is historical, claiming that people have been using it for generations without evidence of harm. As well, if the compounds are on the TGAs list of generally recognised are safe materials extensive safety testing is not required.
The TGA utilizes post marketing follow-up to check for compliance with the listed medicine regulations. This follow-up consists of random surveys as well as targeted surveys from concerns raised by consumers.
In Australia, nearly 2,000 new herbal medications are registered per year. In a TGA survey in 2012 -2 013, 145 complementary medications were tested. Around 83% of complimentary medications surveyed were deemed to be non-compliant, with 6% failing due to product composition, formulation or manufacturing.
Using a combination of new molecular approaches, our survey received a much higher level of adulteration and contamination in TCMs than found in the TGAs surveys. Adding DNA ingredient screening to the TGAs armoury of analytical methods would help ensure that undeclared ingredients are not included in the herbal medications we consume.
And Finally :
The herbal medicine industry is a billion dollar international industry, with products travelling all over the world.
Globally, we need a better auditing toolkit to ensure consumers of herbal medications, as well as people testing their efficacy, are not being misled.
This research, we think, provides a roadmap to more effective regulation of the herbal medicine sector.
* The results of our screening have been passed on to the TGA, which is following this up .
Ian Musgrave, Senior lecturer in Pharmacology
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