Hyphenated Approaches for the Analysis of Bioactive Natural Compounds in Complex Matrices

Plants, animals and micro-organisms represent a reservoir of natural products, the so called “natural source-derived compounds”. This is particularly true for the plant kingdom, as it offers a variety of species still used as remedies for several diseases in many parts of the world. Nevertheless, the bioactive potential of many plant species remains largely unexplored. Thus, biodiversity represents an unlimited source of chemical entities with potential beneficial effects on human health. These compounds are usually secondary metabolites often present in low quantity in plant material and their extraction, purification and quantitation still remain a great challenge for analytical scientists. The research activity carried out during these three years of PhD Programme was focused on the development, validation and application of original methods aimed at the quali-quantitative analysis of compounds with potential bioactive interest in plant matrices, foods, drinks and related products, as well as the analytical screening of plant by-products from cosmetic manufacture. Bioactive substances, belonging to the classes of polyphenols, aminoacids, coumarins, triterpenes and phytohormones, have been investigated as authenticity markers, in order to identify high quality products and to valorise niche products. The study regarded herbs (Argania spinosa), fruits (Citrus × myrtifolia, Punica granatum) and berries (Myrtus communis) mainly used as folk medicines for their broad spectrum of supposed pharmacological and therapeutic effects. The analytical methods developed within this study are based on high performance liquid chromatography and ultra-high performance liquid chromatography coupled to spectrofluorometric detection, triple quadrupole and high-resolution triple quadrupole mass spectrometry (HPLC-F, LC-MS/MS and UHPLC-HRMS). Significant efforts have been put also into the development and optimisation of miniaturised sample pretreatment strategies, such as micro-solid phase extraction (µSPE) and micro-extraction by packed sorbent (MEPS), able to purify complex matrices of natural origin (whole fruits, fruit parts, leaves and their extracts) and derived commercial products.