Pharmaceutical botanical studies on the taxa of Papaver L. sect. Rhoeadium Spach (Papaveraceae) in Türkiye

In this study, thirteen taxa belonging to the section Rhoeadium of the genus Papaver were comprehensively evaluated in terms of taxonomy, anatomy, palynology, seed micromorphology, molecular characteristics, and phytochemical composition. The main objectives were to clarify the taxonomic boundaries of the taxa, elucidate their phylogenetic relationships, and correlate their phytochemical profiles with biological activities. As a result of the taxonomic assessments, the number of taxa previously reported for this section in the Flora of Turkey was revised from sixteen to thirteen. Anatomical investigations of the root, stem, leaf, and calyx revealed distinct interspecific differences in tissue organization. All pollen grains were of the tricolpate type, with exine ornamentation ranging from microechinate–reticulate to perforate forms. Seed micromorphological analysis indicated that variations in anticlinal wall patterns possess diagnostic value at the taxon level. Phylogenetic analyses based on ITS and chloroplast gene regions (PP = 1.0; BS = 100) confirmed the monophyletic structure of the genus and revealed the presence of three main clades. Phytochemical analyses, performed using the LC-MS/MS method, identified a total of 108 compounds (34 alkaloids and 74 phenolic/flavonoit derivatives). Additionally, 85 volatile constituents were characterized in the essential oil obtained by microdistillation. The total phenolic content (TPC) ranged from 28.6 to 147.8 mg GAE/g and showed a positive correlation with DPPH radical scavenging activity (17.41– 46.48%). Lipoxygenase (LOX) inhibition was highest in P. dubium subsp. laevigatum (50.43%) and P. purpureomarginatum (49.70%). Ethanol extracts exhibited weak antibacterial and anticandidal activities. Overall, this study provides detailed and original data on the anatomy, palynology, molecular structure, biological activity, and phytochemical composition of Papaver sect. Rhoeadium taxa, thereby establishing a valuable foundation for future multidisciplinary research. Keywords: Biological activity, Essential oil composition, Phytochemical analysis, Papaver, Taxonomy.