Biosynthesis of Silver Nanoparticles Using Carica Papaya Aqueous Leaf Extract and Their Antibacterial and Antiproliferative Activity Against Cancer Cell Lines

This study explores a green, eco-friendly approach for synthesizing silver nanoparticles (AgNPs) using aqueous leaf extract of Carica papaya. The plant extract acts as both a reducing and stabilizing agent, leading to the formation of biologically active nanoparticles. Characterization of the synthesized nanoparticles was performed using UV–Visible spectroscopy, FTIR, XRD, and SEM, confirming the presence of stable, spherical silver nanoparticles with a crystalline face-centered cubic structure averaging around 200 nm in size. Phytochemical analysis revealed the presence of bioactive compounds—such as flavonoids, phenols, and alkaloids—that contribute to the reduction and stabilization processes. The Cp-AgNPs Ag-NPs demonstrated notable antibacterial activity against both Staphylococcus aureus and Escherichia coli, with stronger effects observed against Gram-negative strains. Furthermore, the antiproliferative potential of Cp-AgNPs was assessed using the MTT assay on various human cancer cell lines (MCF-7, A549, HCT-116, and Caco-2), showing a dose-dependent decrease in cell viability. These findings highlight the potential of Carica papaya-mediated silver nanoparticles as promising candidates for antimicrobial and anticancer applications, aligning with sustainable practices in nanomedicine. Key words: Ag-NPs (Silver nanoparticles), Carica papaya, MTT Assay , MCF-7, A549, HCT-116, Caco-2