NMR Triple ressonance micro probes: applicability for metabolomic studies of citotoxic plant extracts from Cerrado and Atlantic Rainforest

Abstract

The need for new and innovative analytical methods that may shed information towards complex natural matrixes composition is a keystone on bioprospecting programs. Dereplication methodologies associated to state of the art spectroscopic techniques as well as in vitro bioassays, have been successful in the selection of biologically active extracts. Our research group "NuBBE" (Nuclei of Bioassays, Biosynthesis and Ecophysiology of Natural Products) has incorporated experimental strategies and chromatographic methods to select, from our bank of extract, promising candidates for further studies. Recently the use of high performance liquid chromatography (HPLC) hyphenated with high resolution mass spectrometry (HRMS) allowed us to analyze plant and endophytic fungi extracts speeding up the selection of biologically active fractions as well as assisting on chemical composition studies of the known bioactive chemotypes and selecting those with novel molecular characteristics for further separation and purification. Innovative spectroscopic techniques using Nuclear Magnetic Resonance (NMR) recently applied on the study of dynamic complex matrixes are being integrated with HPLC methods mainly due to their robustness, low sample amounts and spectroscopic versatilities. Prof. Arthur Edison's group at the University of Florida (UFl), USA, is nowadays a reference research center in the development of analytical methods using diverse NMR techniques as well as several in vitro and in vivo bioassays. The goal of this proposal is to strengthen the collaboration between our research groups towards training and development of analytical methodologies that increase the understanding of molecular relationships on dynamic natural matrixes and thus, establishing a rational approach for the study of bioactive natural products. To fulfill this task an array of plant species belonging to Lecythidaceae, Euphorbiaceae, Rubiaceae, Bignoniaceae and Asteraceae families having little phytochemical studies but promising citotoxicity were selected to apply these new analytical methods. (AU)