Combining analytical tools to identify adulteration: some practical examples

The European Pharmacopoeia (Ph. Eur.) is the legal and scientific reference for the quality control of medicines, including herbal drugs (HDs) and their preparations (HDPs). Typically, quality is defined using markers or active constituents by the means of HPTLC, HPLC, GC. Nevertheless, substitution or adulteration of HDs and HDPs either intentionally, e.g. motivated by the desire to maximize financial gains, or unintentionally, e.g. by clerical errors or lack of knowledge, is not a rare occurrence and can have tragic consequences.

Diverse analytical methods including DNA fingerprinting, Nuclear Magnetic Resonance (NMR), Near InfraRed (NIR) and (bio)sensors can be very useful as integrative/ alternative analytical methods. Identification of plants at the species level can be successfully based on genome-based methods, using DNA barcodes, the nucleotide sequence of a short DNA fragment, as in the case of different species of goji berry. NMR can provide direct NMR fingerprint determination (complete assignment of the signals by 1D and 2D experiments), and fully characterize different commercial extracts of ginkgo or even complex HDPs mixtures. NIR spectroscopy is a fast qualitative and quantitative analytical method, getting knowledge about substitution of plant species, i.e. star anise and the neurotoxic Japanese star anise, Stephania tetrandra and the nephrotoxic Aristolochia fangchi. Finally, chemical and biological sensors represent one of the most interesting analytical tool because of the versatility of the recognition element able to recognize the presence of undefined DNA intercalating constituents or specific classes of metabolites could be related to the substitution or adulteration [1], [2].

• References

• 1 Bilia AR. J Ethnopharmacology 2014; 158 (Part B): 487-494.
• 2 Bilia AR. Pharmaceutical Analysis | Plant Extracts. Encyclopedia of Analytical Science. 3rd ed.. Elsevier: Editor-in-Chiefs: Paul Worsfold Alan Townshend Colin Poole Manuel Miró; 2019: 219-230 . ISBN: 9780081019832