Cytotoxic and apoptotic effects of Fe, Cu, and Ag nanoparticles synthesized with sage (Salvia officinalis) extract on rainbow trout gonad cell line

The rapid increase in the use of nanoparticles in various sectors necessitates understanding their potential biological effects on aquatic organisms. In particular, the biosafety profiles of plant-derived biosynthetic nanoparticles, developed as environmentally friendly alternatives, are still known to a limited extent. In this study, the cytotoxic and apoptotic effects of iron (Fe), copper (Cu), and silver (Ag) nanoparticles obtained by green synthesis using sage ( Salvia officinalis ) leaf extract on rainbow trout ( Oncorhynchus mykiss ) gonad cell line (RTG-2) were investigated. The structural and morphological properties of the synthesized nanoparticles were characterized by UV–Visible spectroscopy, FT-IR, X-ray diffraction (XRD), scanning electron microscopy (SEM)-EDX, and zeta potential analyses. Cell viability and apoptosis-related protein responses were assessed following nanoparticle exposure. The results showed that all metal nanoparticles produced a concentration-dependent cytotoxic effect in RTG-2 cells. Silver nanoparticles (AgNPs) exhibited the strongest cytotoxic effect, significantly reducing cell viability, especially at concentrations of 50 µg/mL and above. Apoptosis analysis revealed that different toxicity mechanisms were activated depending on the metal type. While AgNPs strongly suppressed BCL2 expression and appeared to enhance apoptosis-related responses, CuNPs and FeNPs were mainly associated with p53-mediated cellular stress signaling. In conclusion, it was shown that sage-derived metal nanoparticles produced metal-type-specific cytotoxic and apoptotic effects in fish gonad cells; these findings highlight the necessity of species- and metal-based approaches in the environmental risk assessment of green synthesis nanoparticles. © 2026 Elsevier B.V.