Advances in Techniques for Profiling Crude Extracts and for the Rapid Identification of Natural Products: Dereplication, Quality Control and Metabolomics

Thanks to the important advances registered over the last decade in analytical techniques, profiling methods for the analysis of crude extracts from plant origin or from other biological sources have evolved into powerful tools for dereplication, quality assessment and metabolomics. Metabolite profiling of crude extracts represents a challenging analytical task since these mixtures are composed of hundreds of natural products. According to the type of study the focus can be put on major bioactive constituents or minor significant biomarkers. In many cases, a rapid on-line or at-line identification of the compound(s) of interest and in some case of all detected constituents (metabolomics) is required. The most common techniques for these types of analyses consist of a spectroscopic method hyphenated to high performance liquid chromatography (HPLC), such as liquid chromatography photodiode array detection (LC-PDA), mass spectrometry (LC-MS) or nuclear magnetic resonance (LC-NMR). With the evolution of multivariate data analysis (MVDA) methods, profiling extracts may also rely on direct NMR or MS analysis without prior HPLC separation, which requires high resolution instruments. In this review most of the current technologies for profiling natural products in various matrices will be presented and discussed. Various applications in the field of dereplication, quality assessment or metabolomics will illustrate the latest analytical strategies employed.