HPLC-MS and NMR spectroscopy: two integrative analytical tools for the quality control of plant extracts, the case of a commercial blend sold as dietary supplement

In this study HPLC-DAD-ESI-MS, HPLC-ESI-MSⁿ and 2D NMR techniques were applied for the quality control of a herbal supplement. Several reports were received by the pharmacovigilance system by patients who fainted after consuming „)Olivis(lrquor)), a dietary supplement for the integrative treatment for hypertension. Declared components of this product are extracts from Olea europaea L., Crataegus oxyacantha L., Fumaria officinalis L., Capsella bursa-pastoris (L.) Medik. „)Olivis(lrquor)) sample was subjected, after lyophilization, to direct 2D NMR and HPLC-DAD-ESI-MS analyses to identify the marker constituents of the different Herbal Drugs. Comparison of the NMR and chromatographic profiles of the product with those of the marker compounds of the declared plant species, (such as oleuropein, protopine), showed the lack of the latter. Samples of the declared plant species were taken into consideration as well. Comparison of these samples with the commercial product revealed marked differences in their content. Further, HPLC-DAD and HPLC-ESI-MS analyses showed the presence of Rauwolfia sp. type indole alkaloids, while HPLC-ESI-MSⁿ analyses revealed the presence of reserpine. Parallel phytochemical fractionations led to the isolation of ajmaline. Quantitation studies showed that (i) the content of reserpine in the product was in the therapeutic range and therefore responsible for the collapses of the patients; (ii) ajmaline prevailed against reserpine indicating that a Rauwolfia species other than R. serpentina was used. The present study shows the importance of extensive controls using combined analytical tools of the botanical products on the market to assure their quality and as a consequence their safety profiles.

Keywords: HPLC-UV-DAD-MS profile, NMR profile, dietary supplement, adulterant, reserpine, ajmaline