Muhammad Usman1, Bazgha Maryam2, Muhammad Qamar Abdullah3, Muhammad Ahmad1, Maria Aziz5, Sobia Aziz6, Mah Noor3,* and Adil Sana4
1Department of Biochemistry and Biotechnology, Muhammad Nawaz Shareef University of Agriculture, Multan, Pakistan; 2Department of Plant Breeding and Genetics, Faculty of Agriculture and Environmental Science, the Islamia University of Bahawalpur, Pakistan; 3Department of Poultry Science, Muhammad Nawaz Sharif University of Agriculture, Multan, Pakistan; 4Department of Microbiology and Molecular Genetics, the Women University, Multan, Pakistan; 5Department of Chemistry, Government College University, Lahore, Pakistan; 6Department of Chemistry, Bahauddin Zakariya University, Multan, Pakistan
*Corresponding author: namalnoor333@gmail.com
In recent years, biological extracts have emerged as promising agents for the rapid synthesis of silver nanoparticles (AgNPs) exhibiting strong antibacterial properties. This study was designed to synthesize and optimize silver nanoparticles (AgNPs) using the leaf extract of Moringa oleifera. Fresh M. oleifera leaves were boiled to prepare aqueous extracts, which were mixed with 1 mM AgNO? solution under direct sunlight to drive nanoparticle formation. A distinct color change from pale yellow to dark brown within 30 minutes indicated AgNPs synthesis, which was confirmed using UV–Vis spectroscopy (SPR peak at 434 nm). The antimicrobial activity of the synthesized AgNPs was evaluated against Escherichia coli and Pseudomonas aeruginosa using well diffusion and disc diffusion assays. Biosynthesized AgNPs exhibited strong antibacterial potential. In well diffusion, inhibition zones were 15.0±0.5, 17.8±0.7, and 20.2±0.8mm at 25, 50, and 100µg/mL, respectively. In disc diffusion, inhibition zones were 21.5±1.5mm (50µg/disc) and 27.3±2.0mm (100µg/disc). Minimum inhibitory concentration (MIC) analysis revealed complete inhibition of E. coli growth at 5.0mM AgNP concentration, showing a clear dose-dependent effect. This study demonstrates a green, cost-effective, and efficient method for AgNP synthesis using M. oleifera leaf extract. The nanoparticles displayed significant antimicrobial activity, suggesting their potential application as broad-spectrum antimicrobial agents in biomedical and environmental domains.