Phytomediated Synthesis of Silver Nanoparticles via Endemic Cousinia sivasica Leaf Extract: Characterization and Cytotoxic Evaluation

In this study, silver nanoparticles were synthesized from an endemic plant, Cousinia sivasica (AgNPs@Cs), for the first time and evaluated for cytotoxic activity. The characterization of AgNPs@Cs was performed via ultraviolet‐visible spectroscopy (UV–Vis), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), energy‐dispersive X‐ray spectroscopy (EDX), zeta potential, and field emission scanning electron microscopy (FE‐SEM). The cytotoxic activity of C. sivasica extract and AgNPs@Cs was examined against human cancer cells, including glioblastoma (U‐87), colon (HT‐29), breast (MCF‐7 and MDA‐MB‐231), prostate (DU‐145 and PC‐3), pancreas (PANC‐1), cervical (HeLa), and normal mouse adipose fibroblast cells (L‐929) using MTT assay. The IC 50 values of the extract after 48‐h treatment were found to be higher than those of AgNPs@Cs and cisplatin against all examined cell lines. AgNPs@Cs showed higher cytotoxic activity against MDA‐MB‐231 and PC‐3 cells and exhibited comparable cytotoxicity against DU‐145 cells relative to cisplatin as the reference drug. AgNPs@Cs showed no cytotoxicity toward HT‐29, PANC‐1, and HeLa cells, even at a concentration of 50 μg/mL. Cisplatin was found to be more cytotoxic (3.85‐fold) than AgNPs@Cs against L‐929 cells. While the extract and cisplatin exhibited low (< 1) selectivity for cancer cells, AgNPs@Cs showed higher selectivity indices for DU‐145 and MCF‐7 cells (1.18 and 1.16, respectively).