DNA-based authentication: incorrect use and exaggerated expectations damage a valuable approach

Analysis of DNA with molecular methods is omnipresent in our everyday life. One of the many different applications is the identification of biotic materials useful for proofing presence (authenticity) or absence of certain organisms. The importance of molecular biology has led to the development of a plethora of methods and a wealth of information in public databases. However, application of sophisticated technology in a new field can take wrong turns, if expectations are wrong or too high, methods are incorrectly applied or results not critically interpreted.

Authentication of medicinal plants is a challenging task. DNA-based authentication is a wonderful supplementation and is already widely applied in risk management of critical medicinal plants. However, practical application in our sector during the last decade has uncovered vulnerabilities that are often not linked to the methods but rather to the way of their application.

DNA-based authentication needs expert knowledge: with advanced equipment and bioinformatics, many procedures of species identification can be automated to a high degree, which often misleads to an uncritical view on results. DNA-based authentication needs expertise in both, molecular methods and pharmacognosy.

Expectations: qualitative identification needs to be strictly distinguished from quantitative analysis. Although reliable quantitative molecular methods are available, and qualitative methods are run on quantitative equipment, standard barcode markers cannot be used for quantification at all.

Considering the peculiarities of medicinal plants raw materials, intermediates and products, DNA-based authentication is a useful approach but needs careful adaptation and harmonization. However, harmonization may not be so easy if freedom of action using molecular options should not be narrowed.