Evaluating the Synergetic Effect of Nigella sativa Extract and Metal Oxide Nanoparticles Against Different Microbes

Abstract

BackgroundThe emergence of antibiotic-resistant bacteria necessitates the exploration of alternative antimicrobial agents. Nigella sativa (black seed) and metal oxide nanoparticles have independently shown antimicrobial properties, but their synergetic effects remain understudied. ObjectiveThis study investigated the individual and combined antimicrobial activities of Nigella sativa extract with zinc oxide (ZnO), manganese-doped zinc oxide (Mn-ZnO), and cobalt-doped zinc oxide (Co-ZnO) nanoparticles against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. MethodsNanoparticles were synthesized via co-precipitation method and characterized using UV-Vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). N. sativa extract was prepared through maceration in 70% methanol. Antimicrobial activity was assessed using agar well diffusion assay and minimum inhibitory concentration (MIC) determination. ResultsNanoparticles demonstrated significant antimicrobial activity against E. coli (inhibition zones: 2.5-2.7 cm) but showed no activity against S. aureus and P. aeruginosa. Conversely, N. sativa extract exhibited antimicrobial activity against S. aureus and P. aeruginosa (inhibition zones: 2.0-2.2 cm) but not against E. coli. No synergetic effect was observed when nanoparticles and N. sativa extract were combined. ConclusionThe study revealed complementary but non-synergistic antimicrobial activities between N. sativa extract and metal oxide nanoparticles. Future research should investigate the molecular mechanisms preventing synergy and explore potential antagonistic interactions.