Metabolomics and chemophenetics support the new taxonomy circumscription of two South America genera (Barnadesioideae, Asteraceae)

Dasyphyllum Kunth is the most diverse genus of the South American subfamily Barnadesioideae (Asteraceae), comprising 31 species most of which are distributed along the Brazilian Atlantic Forest, Cerrado and Caatinga domains. The genus has traditionally been divided into two subgenera, namely Archidasyphyllum and Dasyphyllum. However, recent phylogenetic, morphological, and biogeographical evidence led to a new circumscription of Dasyphyllum by elevating the subgenus Archidasyphyllum to the generic rank. The present work aimed to explore a chemophenetic characterization of Dasyphyllum for further supporting its new circumscription by a metabolomic approach using liquid chromatography coupled to high resolution mass spectrometry and multivariate statistical analyses. A total of 44 mass features were identified based on their UV spectra, high resolution MS data and MS2 fragmentation patterns as well as comparisons with standard compounds. Dasyphyllum samples exhibited a diversity of phenylpropanoids: 3-O-caffeoylquinic acid, 4-O-caffeoylquinic acid, 5-O-caffeoylquinic acid, 5-O-feruloylquinic acid, 5-O-caffeoylshikimic acid, 1,3-O-dicaffeoylquinic acid, 3,4-O-dicaffeoylquinic acid, 3,5-O-dicaffeoylquinic acid and 4,5-O-dicaffeoylquinic acid. On the other hand, Archidasyphyllum displayed the 2-O-caffeoyltartaric acid, 2,3-O-dicaffeoyltartaric acid and caffeoyl-feruloyltartaric acid as distinctive constituents. The occurrence of tartaric acid ester derivatives in Archidasyphyllum and its absence in Dasyphyllum may constitute a diagnostic chemical characteristic for further supporting the segregation of Archidasyphyllum from Dasyphyllum. The occurrence of phenylpropanoids in Archidasyphyllum and Dasyphyllum is here reported for the first time. (AU)