Search

Hadamard transform atmospheric pressure ion mobility-MS and rapid UHPLC-MS methods were investigated for analysis of closely related isomeric flavonoids and their glycosides using a test set of seven standards. On a time scale of a few minutes, the flavonoid aglycones were all separated by ion mobility, but not by UHPLC. The glycosides were better resolved by IMS but not completely separated by both methods. The results suggest that IMS provides sufficient resolution for separation of isomeric polyphenols such as flavonoids in high-throughput metabolomics studies.

Advances in analytical methods and bioassay development have helped to push forward the research in natural products. In plant extracts and nutraceuticals, bioactive compounds are part of a complex mixture. The development of high-resolution methods related to HPLC for both chemical and biological profiling has significantly increased the efficiency of classical bioactivity-guided fractionation procedures. Furthermore, the level of sensitivity obtained by these methods give the possibility to work with few micrograms of compound. This represents a key advantage for rapid localisation of the biological activity and subsequent identification of the compounds of interest. The same methods are also used to study the extracts from a metabolomic view point. The possibility to study them as a whole can highlight synergetic effects, which are likely to occur in plant extracts and nutraceuticals. In this paper, the main trends are summarised and the developments made in our laboratory on profiling crude extracts with UHPLC-TOF-MS, natural product identification at the microgram level using microflow NMR and integration of these methods with biological evaluation are highlighted.