Traditionally used medicinal plants mediate the biosynthesis of silver nanoparticles: methodological, larvicidal, and ecotoxicological approach.

It has been shown that vegetal species constitute an alternative natural source for the biosynthesis of new nanomaterials. Thus, aiming to expand knowledge about the potential use of plants in the fabrication of metallic nanomaterials, we aimed to synthesize silver nanoparticles (AgNPs) from phyto-formulation (PF) of ten commonly used medicinal plants. Our results demonstrate the formation of spherical, stable, polycrystalline AgNPs with a diameter of 8.42 nm to 18.40 nm, whose biosynthesis confirmation was performed via UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FE-SEM)-energy dispersive X-ray spectroscopy (EDS) mapping, high-resolution transmission electron microscopy (HR-TEM), dynamic light scattering (DLS), and zeta potential studies. Furthermore, we demonstrated that the biosynthesized AgNPs showed larvicidal activity against Aedes aegypti and Anopheles stephensi larvae, with the histopathology findings from the fourth instar larval stage validating such larvicidal toxicity. The histological examinations showed severe degradation of the larvae's hindgut, epithelial cells, midgut, and cortical area. However, the PF extract and the biosynthesized AgNPs showed high ecotoxicity in Danio rerio larvae exposed to different concentrations. The treatments induced changes in hatchability percentage, animal growth, and heartbeat. Therefore, despite supporting the potential of PF (from ten plant species) as a raw material source for AgNPs biosynthesis, our study also sheds light on its ecotoxicological potential, suggesting that more comprehensive assessments of the ecotoxicity of biosynthesized would be performed before its application in different sectors.