Cytotoxicity effects induced by silver and 4-chlorochalcone nanoparticles synthesized using Mentha spicata L. on breast cancer MDA-MB-231, MCF-7 cell lines and healthy MRC-5 fibroblasts

Silver nanoparticles (AgNPs) synthesized using plant extracts have attracted increasing attention due to their potential biomedical applications, including anticancer activity. However, the influence of synthesis conditions and nanoparticle functionalization on their cytotoxic effects remains insufficiently understood. In this study, we aimed to evaluate the cytotoxic activity of silver nanoparticles synthesized using Mentha spicata L . (spearmint) extract and functionalized with 4-chlorochalcone (AgNPs-Ms-4Cl-CH) against breast cancer cells. To enhance nanoparticle yield by reducing the high electric polarity of the reactants, the synthesis was carried out in a high-pressure cell. The resulting nanoparticles were characterized using Ultraviolet-Visible spectroscopy (UV–vis), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Transmission Electron Microscopy (STEM) determined a mean core particle size of 44.7 ± 13.7 nm. Quantitative energy-dispersive X-ray (EDX) elemental mapping confirmed silver as the predominant constituent (62.49 wt%), with chlorine (0.51 wt%) serving as a diagnostic tracer for 4-chlorochalcone surface functionalization and demonstrating homogeneous spatial distribution across the nanoparticle ensemble. Complementary colloidal characterization by dynamic light scattering (DLS) and electrokinetic light scattering (ELS) revealed a monodisperse hydrodynamic suspension in DMEM culture medium (Rₕ = 62.0 nm, FWHM = 8.0 nm; polydispersity index < 0.15) with a zeta potential of −30 mV, confirming robust electrostatic stabilization suitable for biological applications. The cytotoxic effects of different concentrations of AgNPs-Ms-4Cl-CH were assessed in two breast cancer cell lines (MDA-MB-231 and MCF-7) and compared with healthy MRC-5 fibroblasts. In vitro assays demonstrated that AgNPs-Ms-4Cl-CH significantly reduced cell viability and proliferation in all tested cell lines. Notably, the MDA-MB-231 cells exhibited a lower IC₅₀ value, indicating greater sensitivity to the nanoparticles. These findings highlight the cell line–dependent cytotoxicity of AgNPs-Ms-4Cl-CH and emphasize the importance of considering cellular origin when evaluating nanoparticle toxicity. Further studies are warranted to elucidate the mechanisms underlying nanomaterial–cell interactions.