GREEN SYNTHESIS OF SILVER NANOPARTICLES USING HIBISCUS SABDARIFFA FLOWER EXTRACT AND THEIR SYNERGISTIC ANTIMICROBIAL, ANTIOXIDANT, AND CYTOTOXIC ACTIVITIES

The rise of multidrug-resistant pathogens has heightened global interest in developing alternative therapeutic strategies to overcome the limitations of conventional antibiotics.In this study, silver nanoparticles (AgNPs) were synthesized using a green chemistry approach, with Hibiscus sabdariffa leaf extract serving as a natural reducing and stabilizing agent. The synthesized nanoparticles were characterized using ultraviolet - visible spectroscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction, which confirmed the successful formation of nanoparticles with a predominantly spherical morphology and an average particle size of 45 nm. Antimicrobial activity assays against Escherichia coli and Staphylococcus aureus showed inhibition zones of 23 mm and 28 mm, respectively, which exceeded those produced by the plant extract alone. Antioxidant analysis revealed strong, dose-dependent radical-scavenging activity, with AgNPs exhibiting 91% inhibition of 2,2-diphenyl-1-picrylhydrazyl at 150 ug/mL, compared with 75% for the crude extract.