Data from: Veronica officinalis product authentication using DNA metabarcoding and HPLC-MS reveals widespread adulteration with Veronica chamaedrys

Studying herbal products derived from local and traditional knowledge and
their value chains is one of the main challenges in ethnopharmacology. The
majority of these products have a long history of use, but non-harmonized
trade and differences in regulatory policies between countries impact
their value chains and lead to concerns over product efficacy, safety and
quality. Veronica officinalis L. (common speedwell), a member of
Plantaginaceae family, has a long history of use in European traditional
medicine, mainly in central eastern Europe and the Balkans. However, no
specified control tests are available either to establish the quality of
derived herbal products or for the discrimination of its most common
substitute, V. chamaedrys L. (germander speedwell). In this study, we use
DNA metabarcoding and high performance liquid chromatography coupled with
mass spectrometry (HPLC-MS) to authenticate sixteen V. officinalis herbal
products and compare the potential of the two approaches to detect
substitution, adulteration and the use of unreported constituents. HPLC-MS
showed high resolution in detecting phytochemical target compounds, but
did not enable detection of specific plant species in the products. DNA
metabarcoding detected V. officinalis in only 15% of the products, whereas
it detected V. chamaedrys in 62% of the products. The results confirm that
DNA metabarcoding can be used to test for the presence of Veronica
species, and detect substitution and/or admixture of other Veronica
species, as well as simultaneously detect all other species present. Our
results confirm that none of the herbal products contained exactly the
species listed on the label, and all included substitutes, contaminants or
fillers. This study highlights the need for authentication of raw herbals
along the value chain of these products. An integrative methodology can
assess both the quality of herbal products in terms of target compound
concentrations and species composition, as well as admixture and
substitution with other chemical compounds and plants.