In this research, Magnesium oxide nanoparticles (MgONPs) was prepared from MgCl2 solution using aqueous extract of M. oleifera bark as green agent. Preparation procedure involved mixing of MgCl2.6H2O solution and the aqueous extract of M. oleifera bark, followed by drop wise addition of NaOH solution. The formation of MgO nanoparticles in this synthesis was confirmed using UV-Vis absorption. The spherical crystal structure of MgO nanoparticle confirmed XRD analysis. The average particle size of the synthesized MgO nanoparticles measured between 60 - 100 nm using SEM and TEM images and PSA results. MgONPs synthesized showed good antioxidant activity and antibacterial activity against S. aureus, E. faecalis, E. coli, and S. dysenteriae bacteria.

Nanoparticle fabrication using plant extracts is an important alternative method because it is non-toxic, biocompatible, and environmentally friendly. In this study, green synthesis of MgO nanoparticles using Moringa oleifera leaf water extracts was conducted by mixing the extract and a solution of magnesium chloride. The product was characterized using different techniques, i.e. UV-Visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The UV-Vis spectrum of MgO nanoparticles shows an absorption at 280 nm. The size of the synthesized MgO nanoparticles ranges from 20-50 nm. The antibacterial activity of MgO nanoparticles was seen from the zone of inhibition against Staphylococcus aureus (6.3 mm) and against Escherichia coli (6 mm). MgO nanoparticles have been successfully fabricated using Moringa oleifera leaf aqueous extracts, providing an alternative method for synthesizing MgO nanoparticles.                     KEY WORDS: Antibacterial activity, Escherchia coli, MgO nanoparticles, Moringa oleifera, Staphylococcus aureus   Bull. Chem. Soc. Ethiop. 2021, 35(1), 161-170. DOI: https://dx.doi.org/10.4314/bcse.v35i1.14

In this research, nano-size MgO (NS-MgO) was prepared from MgCl2 solution using aqueous extract of Moringa oleifera leaves (AEMOL) as green agent. Preparation procedure involved mixing of MgCl2.6H2O solution and the AEMOL, followed by dropwise addition of NaOH solution. The formation of NS-MgO in this synthesis was confirmed using UV-Vis absorption. The spherical crystal structure of NS-MgO was confirmed by XRD analysis. The average particle size of the synthesised NS-MgO was found between 40–70 nm using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images and particle size analyser (PSA) results. Based on the maximum inhibition concentration (MIC) it was found that the NS-MgO has good antibacterial activity against S. aureus, E. faecalis, E. coli, and S. dysenteriae bacteria (MIC values: 250–500 μg ml−1), and much stronger antifungal activity against A. flavus, A. niger, and C. albican (MIC values: 62.5–125 μg ml−1). These findings suggest prospective potential of NS-MgO synthesised as therapeutic candidate for the treatment of candidiasis.

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Umumnya bahan pangan berupa ikan dan daging olahan merupakan bahan pangan yang mudah rusak (perishable food) karena kandungan protein dan air yang cukup tinggi, oleh karena itu perlakuan dan pengolahan yang baik sangat diperlukan untuk bahan pangan tersebut. Adapun tujuan dari penelitian ini adalah untuk mendeteksi bakteri Salmonella sp dengan media SSA (Salmonella shigela agar) dan E-coli dengan media EMBA (Eosin Methylene Blue Agar) pada beberapa bahan pangan yang berasal dari ikan dan daging olahan. Sampel yang diuji berupa daging ikan giling, ikan asin, makanan kaleng dan sosis. Metode yang digunakan adalah uji pendugaan dengan menggunakan media selektif SSA dan EMBA dengan teknik media tuang. Hasil penelitian ini menunjukkan bahwa semua bahan pangan yang diuji untuk mendeteksi adanya Salmonella Sp. dengan menggunakan media SSA menunjukkan hasil yang negatif. Untuk uji deteksi adanya Ecoli dengan menggunakan media EMBA pada bahan pangan yang diuji menunjukkan sampel daging ikan giling positif mengandung bakteri E-coli.