Green synthesis of silver nanoparticles using the aqueous extract of Capparis sepiaria and their in vitro antibacterial activity

Abstract

The emergence of multidrug-resistant (MDR) microorganisms presents a major global public health challenge, necessitating the development of innovative antimicrobial agents. Among the strategies being explored, the green synthesis of silver nanoparticles (AgNPs) using medicinal plants has emerged as a sustainable and environmentally friendly approach for developing effective antibacterial materials. This study investigated the green synthesis of AgNPs using an aqueous extract of Capparis sepiaria (Cs-E) and evaluated their physicochemical characteristics, antibacterial activity, and cytotoxicity. UV-Visible spectroscopy, Dynamic Light Scattering (DLS), Fourier Transform Infrared Spectroscopy (FTIR), and Transmission Electron Microscopy (TEM) confirmed the successful synthesis of predominantly spherical Cs-AgNPs with a surface plasmon resonance (SPR) peak at 404 nm and core sizes ranging from 4 to 16 nm. FTIR analysis further demonstrated that CS-E phytochemicals mediated the reduction and stabilisation of the nanoparticles. The Cs-AgNPs exhibited broad-spectrum antibacterial activity against both Gram-negative and Gram-positive bacteria, producing inhibition zones of 9–13 mm and minimum inhibitory concentration (MIC) values ranging from 18.2 to 72.6 μg/mL, whereas Cs-E showed no antibacterial activity at the concentrations tested. Cytotoxicity evaluation revealed dose-dependent effects, with IC50 values of 22.88 μg/mL for KMST-6 fibroblasts and 8.48 μg/mL for HaCaT keratinocytes. Collectively, these findings demonstrate that green-synthesized Cs-AgNPs possess potent antibacterial activity and support their further development as plant-derived antibacterial nanomaterials.