Antibacterial synergistic behaviour of phytosynthesized magnesium oxide nanoparticles with clove essential oil

Abstract

While researchers continue to search for new antibacterial agents, combination therapy as well as nanotechnology-based treatments allure as promising approaches to tackle antibiotic resistance. The present study aimed to phytosynthesize magnesium oxide NPs (MgO NPs and evaluate their potential antibacterial synergistic behaviour with different essential oils (EOs). MgO NPs phytosynthesized using thyme aqueous extract were quasi-spherical with an average size of 55.2 ± 12.8 nm and an elemental composition of 35.39% Mg and 51.07% O, as determined by SEM-EDX. FTIR elicited characteristic functional group peaks, while XRD confirmed their cubic crystal structure. The phytosynthesized MgO NPs and four EOs displayed variable antibacterial activity against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa. The checkerboard assay revealed that only clove and thyme EOs showed synergistic effects in combination with MgO NPs. Notably, MgO NPs-clove EO combination caused significant bacterial membrane damage as compared to their single counterparts in both S. aureus and E. coli. Moreover, oxidative stress was induced, as observed by the significant increase in the antioxidant enzyme activities (superoxide dismutase and catalase). Conclusively, the present results provide insights into the promising compounding of green-synthesized MgO NPs and clove EO as a bio-efficacious and eco-friendly approach to curtail antibiotic resistance.