Liquid Chromatographic Method for the Determination of Caffeoylquinic Acid Derivates in Hieracium pilosella L.

INTRODUCTION: Hieracium pilosella L. is a medicinal plant encountered in Europe in traditional herbal medicinal products. Caffeoylquinic (ortho-dihydroxycinnamic) acid derivatives are characteristic constituents used as analytical markers in the quality control of the herbal material. Until now, the caffeoylquinic acid derivatives have been assayed using a colorimetric method according to the French Pharmacopoeia. OBJECTIVE: To develop an HPLC-method for quantification of caffeoylquinic acid derivatives in H. pilosella. METHODOLOGY: Samples were prepared by methanol extraction of H. pilosella, dried herb. An HPLC method suitable for analysis was developed and validated. The content of caffeoylquinic acid derivatives was determined and expressed as chlorogenic acid. Individual substances in the samples were identified by analyses of UV-MS/MS spectra and by comparisons with spectra and chromatographic retention times of authentic reference substances. RESULTS: Validation showed that the chromatographic method has good selectivity with no interfering peaks. Sensitivity, linearity, repeatability and accuracy were shown to be adequate. In analyses of several batches of H. pilosella, contents of caffeoylquinic acids ranging from 0.7 to 1.9% were found. Compared to the colorimetric method, this newly developed HPLC method is more specific and results in detection of nominally lower amounts of caffeoylquinic acid derivatives. A new acceptance limit of 1.0% instead of 2.5% caffeoylquinic acid, expressed as chlorogenic acid, for H. pilosella, is proposed when using this HPLC-method. CONCLUSION: A newly developed HPLC method is shown to be appropriate for quantitative determination of caffeoylquinic acid derivatives in H. pilosella. Copyright © 2017 John Wiley & Sons, Ltd.

A general analytical platform and strategy in search for illegal drugs.

An effective screening procedure to identify and quantify active pharmaceutical substances in suspected illegal medicinal products is described. The analytical platform, consisting of accurate mass determination with liquid chromatography time-of-flight mass spectrometry (LC-QTOF-MS) in combination with nuclear magnetic resonance (NMR) spectroscopy provides an excellent analytical tool to screen for unknowns in medicinal products, food supplements and herbal formulations. This analytical approach has been successfully applied to analyze thousands of samples. The general screening method usually starts with a methanol extraction of tablets/capsules followed by liquid chromatographic separation on a Halo Phenyl-Hexyl column (2.7µm; 100mm×2.1mm) using an acetonitrile/0.1% formic acid gradient as eluent. The accurate mass of peaks of interest was recorded and a search made against an in-house database containing approximately 4200 substances, mostly pharmaceutical compounds. The search could be general or tailored against different classes of compounds. Hits were confirmed by analyzing a reference substance and/or by NMR. Quantification was normally performed with quantitative NMR (qNMR) spectroscopy. Applications for weight-loss substances like sibutramine and orlistat, sexual potency enhancement (PDE-5 inhibitors), and analgesic drugs are presented in this study. We have also identified prostaglandin analogues in eyelash growth serum, exemplified by isopropyl cloprostenate and bimatoprost. For creams and ointments, matrix solid-phase dispersion (MSPD) was found to give a clean extracts with high recovery prior to LC-MS analyses. The structural elucidation of cetilistat, a new weight-loss substance recently found in illegal medicines purchased over the Internet, is also presented.