Assessment of Antibacterial Activities of Silver Nanoparticles Biosynthesized Using <i>Loranthus Micranthu</i>s Leaf and <i>Nigella Sativa</i> Seed Extracts on Selected Uropathogens

Abstract

The biosynthesis of nanoparticles using natural plant products has been systematically searched for their medicinal properties and potential as alternative antimicrobial agents with fewer side effects compared to synthetic drugs. Despite the growing interest in biosynthesized silver nanoparticles (AgNPs), there is insufficient research information on the use of Loranthus micranthus leaf and Nigella sativa seed extracts for AgNPs biosynthesis. The aim of the study is to biosynthesize AgNPs using L. micranthus leaf and N. sativa seed extracts and evaluates their antibacterial activities against selected uropathogens. The study adopted the experimental design. AgNPs were successfully synthesized by mixing AgNO3 with the ethanolic extracts of L. micranthus and N. sativa. The synthesis process resulted in a colour change from pale yellow to dark brown within 12 hours, reaching maximum intensity after 24 hours. Characterization was performed using UV-Vis spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, and X‑ray diffraction analysis. Furthermore, the efficacy of these crude antibacterial substances and the synthesized AgNPs on selected multidrug-resistant (MDR) bacteria (namely, Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterococcus faecalis, and Proteus mirabilis) isolated from patients with recurrent and long histories of UTIs was evaluated using the Kirby-Bauer disc diffusion method.Both crude plant extracts and synthesized AgNPs demonstrated significant potent activity on MDR uropathogens. E. coli displayed a higher degree of susceptibility to the antibacterial activities of AgNPs with a zone range from 17±0.2 mm to 23±0.3 mm. This study revealed the effectiveness of AgNPs synthesized from plant materials in managing MDR uropathogens.