Characterization and evolution of secondary metabolites in Brazilian Vernonieae (Asteraceae) assessed by LC-MS fingerprinting

Abstract Tribe Vernonieae are well represented in Brazil, mainly by subtribe Lychnophorinae comprising mostly perennial plants that inhabit arid lands, where species have developed a number of adaptations with recognized ecological protective functions, including secondary metabolite diversification. Recent phylogenetic studies indicate that the subtribe is monophyletic, but questions regarding lineage relationships have yet to be resolved. Phytochemical investigations have also been conducted recently and provide information on the secondary metabolite chemistry of Lychnophorinae. Chemotaxonomic studies have also been carried out. However, these phytochemical investigations are fragmentary and non-standardized. Therefore, in this study, 15 species representing the major lineages of the subtribe were selected for phytochemical investigation and reconstruction of the ancestral states of their secondary metabolites. The main secondary metabolites of these species were detected by UHPLC-UV-MS in different types of extract, showing the presence of trans-cinnamic acid derivatives, flavonoids, polyacetylenes and sesquiterpene lactones. The ancestral states of these secondary metabolites were reconstructed by parsimony and indicate the occurrence of 12 putative chemical synapomorphies. In this study, we present for the first time phytochemical and evolutionary studies based on the reconstruction of the ancestral chemical character states on a phylogenetic tree of Lychnophorinae.