Chemical diversity as a predictor of woody and palm medicinal plant versatility in a seasonally dry tropical forest in Brazil

Abstract Understanding how chemical diversity shapes the selection and use of medicinal plants contributes to both ethnopharmacology and bioprospecting. This study compiles comprehensive information on the general and organ-specific chemical composition of 113 woody and palm species used as medicines in the Caatinga, many of which have recognized pharmacological potential. We investigated whether the versatility of medicinal plants, measured by their capacity to treat multiple therapeutic targets, is associated with their chemical diversity. Our goal was to determine how phytochemistry may influence medicinal plant selection within local pharmacopoeias.A systematic review was conducted across four databases (Scopus, Web of Science, PubMed, SciELO), yielding 15,188 records. After duplicate removal and a two-stage screening process, 1267 articles were included. Chemical classes were recorded for each species and plant part. The relationship between chemical diversity and versatility (Relative Importance Index, IR) was tested using phylogenetic generalized least squares (PGLS), controlling for shared evolutionary history. Fourteen chemical classes were identified across the species, with flavonoids, terpenoids, phenols, and tannins being the most frequent. Only the categories “whole plant” and “stem bark” contained all chemical classes. Chemical diversity was positively associated with versatility in the “whole plant”, “stem bark”, and “seed” categories. No significant relationship was detected for the remaining plant parts. More versatile medicinal plants exhibit greater chemical diversity, indicating that phytochemical richness contributes to their broader therapeutic use in local medical systems. The study also reinforces long-standing patterns in the phytochemistry of semiarid environments and expands the chemical evidence base for 113 medicinal species, supporting future ethnopharmacological and bioprospecting initiatives.