Ahmed, Risikat NikeAbdullahi, M.AZakariyah, Rahmat FolashadeGambari-Ambali, Rabiat. OAdeyemi, Sherif DAfonja, A.IAdebisi, O.O2023-04-262023-04-2620152354 1784https://uilspace.unilorin.edu.ng/handle/20.500.12484/9282Silver nanoparticles (AgNPs) were synthesized using a combination of aqueous extract of Thevetia nerifolia and 1mM of silver nitrate (AgNO3) solution to obtain concentrations of 100mg/ml–400mg/ml. Characterization of the particles was done by UV–Vis spectroscopy Fourier transform infrared (FTIR). Antibacterial activity was investigated against Staphylococcus aureus, Escherichia coli and Psedomonas aeruginosa using standard agar well diffusion method. Gentamicin and tetracycline were used as reference antibiotics. The Minimum Inhibitory Concentration (MIC) was achieved by microbroth dilution technique. Minimum Bactericidal Concentration (MBC) was done by plate assay. The mode of action of the particles was evaluated by direct exposure of the cells of selected isolates to the nanoparticles. The presence of phytochemical constituents was examined using standard methods. The total yield of AgNPs of the plant extract was 0.6g. Characterization by UV-visible spectrometry revealed peak absorbance of 0.465 at 452.0nm, while FTIR showed the presence of two (2) functional groups. According to the antibacterial sensitivity assay, the four concentrations exhibited considerable effects against all test isolates. At 400mg/ml, the highest inhibitory activities were observed with S. aureus and E. coli with zones of inhibition measuring 22mm and 20mm respectively. The activity of synthesized particle compared favourably with reference antibiotics. The MIC was obtained at 40mg/ml while MBC was at a higher concentrations. The mode of action showed disruption of cellular components as a result of increased permeability of cell membrane. Following the results of the phytochemical analysis, a total of five (5) bioactive constituents were obtained. It is evident from this study that AgNPs synthesized could be a good candidate in the treatment of conditions caused by the test isolates.enThevetia nerifoliaNanoparticlesPhytochemicalsAgar well diffusionFTIRArticle