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Many countries around the world have laws and legislations that prohibit the use of endangered animals and plants in products. However, their enforcement is particularly difficult when it comes to traditional medicines. According to Esther Kok, Head of Department at Rikilt, this is partly because such products contain many different ingredients. Kok: ‘The current DNA tests focus on one species that is suspected to be present. This new test can identify almost every type of animal or plant present in the medicine simultaneously.’
Miniature barcodes
The researchers based their work on an existing method and adapted in order to use it on traditional medicines. The test is able to recognise certain “barcodes”: pieces of DNA that occur in many animal or plant species, but which also show some slight differences between species. This way, every code is unique for a species. However, the test only works if there is sufficient DNA to work with.
Ingredients are sometimes withheld or, on the contrary, mentioned despite being absent.
Esther Kok, Head of Department at Rikilt
Damaged
That was one of the first problems the researchers encountered. ‘The medicines often contain ground powders and dried products’, Kok says. ‘This heavily damages the DNA, and the challenge then becomes to find recognisable DNA barcodes that have not been damaged.’ The researchers tackled this problem by creating a panel that can recognise twelve DNA barcode regions. ‘It basically allows us to identify all animal species’, says Kok. Plants turn out to be a bit tricky still, as their DNA differs less between species, and because the database containing all known DNA barcodes of different species is not as complete.’
Seized samples
To test the method, the group investigated eighteen different traditional medicines. Most of these had been seized by Dutch customs because they contained endangered species. The researchers found a total of 31 different plant species and 17 animal species. Kok: ‘In the case of most products, the ingredients on the label do not match the contents. Ingredients are sometimes withheld, or on the contrary, mentioned despite being absent.’
Pig or brown bear?
Four samples were found to have no common ingredients between the label and actual contents. An endangered species was found in one of the samples: brown bear. Another sample mentioned brown bear on the label, but it turned out to contain pig. Kok: ‘Sometimes, very expensive ingredients are mentioned on the label for marketing but are not actually used in the products.’ Kok hopes that the test can be put to use within a year. The next step is to make a portable version to allow inspectors to perform the test on-site.
Additional reading (partly in Dutch):
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Detecting mussel toxins without lab animals
WUR en NVWA bundelen labs in Wageningen Food Safety Research