Green synthesis of silver nanoparticles using red peel waste of Pomegranate and its antibacterial and cytotoxic activities

This study aimed to assess the physicochemical properties of silver nanoparticles (AgNPs) and their antimicrobial and anticancer activity. This work reports on a novel, sustainable, and solar-assisted green synthesis of AgNPs using pomegranate (Punica granatum L.) red peel extract, effectively converting agricultural waste into a high-value product through a simple, green, non-polluting, and inexpensive preparation method. The complete characterization of the biosynthesized AgNPs was performed using various analytical techniques. Nanoparticle formation was confirmed by UV-Vis spectroscopy at 373 nm. A face-centered cubic crystalline structure was confirmed by Powder XRD analysis, and the zeta potential was measured as -34.8 mV, which ensured good stability in its colloidal form. Uniform, spherical particles with an average size of 20-30 nm (DLS and TEM) and potential surface properties for biological applications (contact angle 118º were determined. FTIR identified important functional groups related to phytoconstituents that acted as natural reducing and capping agents. The biogenic AgNPs exhibited significant antimicrobial activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacterial species, with high inhibition rates of 93.7% and 96.25%, respectively. The most significant finding is the demonstration of selective cytotoxicity, with respective IC50 values of 74 μg/mL, 17.2 μg/mL, and 21.02 μg/mL for normal baby hamster kidney cells (BHK), hepatocellular carcinoma cells (HEPG2), and breast cancer cells (MCF-7). This superior selectivity highlights their therapeutic potential for cancer treatment with relatively low toxicity toward normal cells, addressing a critical need identified in recent literature for sustainably produced, highly potent nanoparticles.