Impact of locatioon on metabolomic fingerprinting of French artichoke leaves by NMR and Mass spectrometry
Résumé
Artichoke, or Cynara cardunculus subsp. scolymus, is a well-known plant recognized for the nutritional intake of its fruit around the world. Furthermore, it has been shown that leaves also contain compounds with nutritive and therapeutic benefits like anti-oxidative or hepatoprotective effects. In this work, we want to compare the metabolic profile of the leaves of 23 different artichoke varieties collected in France and investigate the variability of their composition. 5 cardoon varieties will be included in our study as cardoon and artichoke, which belong to the same family are very close species. To allow a broader and easier identification of the metabolites, the analysis will be done by combining NMR and Mass Spectrometry (MS). This kind of analysis will also allow to use integrative statistical methods to combine NMR and MS data. All the leaves were extracted using an infusion method. This method used by Evear Extraction allows to obtain an artichoke or a cardoon liquor containing the majority of the compounds known to have biological effects. For integrative methods, it is recommended to carry out the experimental analyses on one identical sample to avoid bias. Our first objective was thus to find the optimal sample preparation method for the two analytical techniques, NMR and liquid chromatography coupled to mass spectrometry (LC-MS). To enable this, different liquor preparations (lyophilisation, protein precipitation, ultrafiltration, simple and double extractions,…) were tested for several artichoke varieties. In parallel, the first compound identifications have been carried out. Analyses by NMR and LC-MS allowed to identify the best preparation to study polar compounds which in our case is ultrafiltration. Additional studies have to be performed for apolar compounds.