Chemosystematics micromolecular evolutionary trends relevant to the Urticaceae family.

The Urticaceae family (Rosales) comprises six tribes containing 61 genera, with about 2000 species distributed throughout tropical and subtropical regions. Taxonomic controversies concerning Urticaceae remain unresolved. This study aimed to characterize the specialized metabolites in Urticaceae genera and tribes in order to define their chemical profiles, micromolecular markers and the group evolutionary trends. Chemosystematic indexes—occurrence number (ON), oxidation index (OI) and skeleton specialization (SS)—and their evolutionary advancement parameters were calculated based on chemical literature data on Urticaceae flavonoids and triterpenes. Principal component analysis and hierarchical clusters were also performed. Altogether, 356 flavonoids and 607 terpenoids were analyzed. Flavonols and flavones with low protection indexes of flavonoid hydroxyls by O-glycosylation were observed. Moreover, triterpenes were predominant in the Urticaceae. The chemometric analysis confirmed that the Cecropieae tribe belongs to the Urticaceae family indicating similarities and dissimilarities due to metabolic micromolecular variability. Chemometric analysis revealed chemical similarities among several tribes of Urticaceae, including Urticeae, Elatostemateae, Boehmerieae, Parietarieae, Forsskaoleeae, and Cecropieae. C-glycosylated flavones in Cecropieae suggest an evolutionary transition consistent with their phylogenetic position in Urticaceae. These results demonstrate the usefulness of chemosystematics as a reliable tool for describing specialized metabolites in Urticaceae and for supporting molecular phylogenetic studies. [ABSTRACT FROM AUTHOR]