Phytogenic silver nanoparticles from two Orchis species: Characterization and biological activities

Green synthesis of silver nanoparticles (AgNPs) using medicinal plants provides an environmentally friendly approach for producing bioactive nanomaterials, but comparative studies of closely related Orchis species remain limited. In this study, AgNPs were phytofabricated using aqueous root extracts of Orchis latifolia and Orchis mascula , followed by physicochemical characterization and evaluation of their antimicrobial, antioxidant, and urease inhibitory activities. Successful AgNP formation was supported by UV–visible spectroscopy, EDX, TEM, DLS, FT-IR, XRD, TGA, and DSC analyses. The nanoparticles were predominantly rounded/spheroidal morphology, with hydrodynamic diameters of 26.92 and 56.87 nm and polydispersity indices of 0.565 and 0.290 for O. latifolia - and O. mascula -derived AgNPs, respectively. XRD analysis confirmed their crystalline face-centered cubic structure, with characteristic Ag reflections corresponding to the (111), (200), (220), and (311) planes. Both AgNPs exhibited broad-spectrum antimicrobial activity against the tested microorganisms. O. latifolia -derived AgNPs showed higher DPPH radical-scavenging activity, reaching 62.72 ± 2.68% at 1000 µg/mL, whereas O. mascula -derived AgNPs demonstrated greater urease inhibitory activity (84.14 ± 1.13%) and generally stronger antimicrobial effects. Flow cytometric analysis further demonstrated substantial membrane damage following AgNP exposure and increased intracellular ROS levels in several microbial species. Overall, the findings demonstrate that closely related Orchis species can fabricate AgNPs with distinct physicochemical and biological properties, representing the influence of plant species-specific phytochemicals on the functionality of phytofabricated nanomaterials.