Browsing by Author "Sinvula, Simasiku"

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    Green synthesis of silver nanoparticles using Moringa oleifera extracts and their evaluation against antibiotic resistant strains of escherichia coli and staphylococcus aureus
    (University of Namibia, 2022) Sinvula, Simasiku
    It is of great concern that bacteria are forming resistance to common antibiotics meant to prevent or cure them. For this reason, researchers are engaged in synthesis of nanoparticles using medicinal plants to solve the problem of antibiotic resistance in bacteria. The aim of the study was to synthesize silver nanoparticles (AgNPs) using M. oleifera extracts and compare antibacterial activities of AgNPs prepared in M. oleifera extracts with AgNPs of common antibiotics (penicillin G and streptomycin) against antibiotic resistant strains of Escherichia coli and Staphylococcus aureus. Synthesized AgNPs were characterized using UV-vis spectroscopy, fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Disc diffusion method was used for initial screening of antibacterial activities and their minimum inhibitory concentration (MIC) was determined. Formation of AgNPs was confirmed by colour change from pale yellow to dark brown-black. UV-vis spectra analysis showed maximum peak of 400-440 nm. FTIR analysis revealed the presence of hydroxyl and carbonyl functional groups, as well as C-N and C-O bonds that might be responsible for capping, stabilizing and reducing AgNPs. SEM analysis revealed crystalline AgNPs with mean average size of 46.49 ± 0.73 nm to 60.96 ± 1.17 nm. The combination of AgNPs with antibiotics showed better antibacterial activities as compared to AgNPs alone and streptomycin alone. Lowest MIC values were 12.5 mg/mL, 1.56 mg/mL and 3.13 mg/mL for Mo-AgNPs, Mo-AgNPs-Penicillin G and Mo-AgNPs-streptomycin combination respectively. It can then be concluded that M. oleifera has strong potential for synthesis of AgNPs, and combination of AgNPs with common antibiotics sheds light in the direction of decreasing odds of antibiotic resistance development of these pathogens.