BIOGENIC SYNTHESIS AND EVALUATION OF SILVER NANOPARTICLE CONTAINING HERBAL PLANT EXTRACT AND ITS ANTIMICROBIAL ACTIVITY

This study reports the green synthesis and evaluation of silver nanoparticles (AgNPs) using aqueous Abelmoschus ficulneus extract as a reducing and stabilizing agent. Phytochemical screening revealed the presence of proteins, flavonoids, carbohydrates, and polyphenols, which facilitated the bioreduction of silver nitrate into stable AgNPs. A distinct color change from colorless to brown indicated nanoparticle formation, which was confirmed by UV–Vis spectroscopy with a characteristic surface plasmon resonance (SPR) peak at 677 nm. Optimization experiments demonstrated that increasing plant extract concentration (12.5–100 mg/mL) and process parameters such as stirring (300 rpm) accelerated nanoparticle synthesis, reducing reaction time from 3 hours to 30 minutes under alkaline conditions. Purification through repeated centrifugation successfully eliminated excess plant metabolites, as confirmed by the absence of peaks in the 200–400 nm range. Characterization revealed hydrodynamic particle sizes ranging from 150.6 to 168.2 nm, with size variations influenced by pH and stirring conditions. Stability studies indicated that the AgNPs remained chemically and physically stable for up to three months under both accelerated (40 ± 2°C, 70 ± 5% RH) and ambient (25 ± 2°C, 60 ± 5% RH) conditions without significant changes in physicochemical properties. These findings confirm that A. ficulneus extract is an effective green source for producing stable, biocompatible AgNPs with promising potential for biomedical applications.