Identification and quality assessment of commercial valerian samples using DNA barcoding and UHPLC-MS

Valeriana officinalis L. (Caprifoliaceae family) has been traditionally used to treat mild nervousness and sleep disorders. The principal chemical constituents are alkaloids (i.e. chatinine, valerine, valerianine and actinidine), organic acids and terpenes (i.e. valerenic acid, isovaleric acid, valeric acid and acetoxyvalerenic) and iridoids (i.e. valepotriate, isovalepotriate), lignanoids (i.e. pinoresinol-4-O-D-glucoside, 8’-hydroxypinoresinol) and flavonoids (i.e. apigenin, luteolin, quercetin).

In the last years, medicinal plants consumption for treatment of minor pathologies has increased. Therefore, medicinal plants must comply with quality, safety and efficacy standards. The aim of this work is to identify and evaluate the quality of a total of seven commercial samples acquired in pharmacies, herbal shops and supermarkets using DNA metabarcoding and HPLC/MS methods.

Taxonomic identity of valerian samples was validated through DNA barcode for the matK region. DNA was successfully extracted from 3 of the 7 samples. The identity of the sequences was evaluated using the mega-BLAST search function in GenBank. These 3 valerian samples were labelled as Valeriana officinalis but they were identified as Valeriana hirtella Kunth. Regarding bioactive compounds, UHPL-MS revealed that the concentration of acetoxyvalerenic acid was from 0.020 % to 0.053 % whereas the content for valerenic acid was from 0.048 % to 0.167 %.

Our study shows the importance to combine DNA barcoding and HPLC-MS to identify correctly botanical species and to quantify bioactive compounds to guarantee the quality and safe of medicinal plants.