Antibacterial, antioxidant properties of Solanum trilobatum and sodium hydroxide-mediated magnesium oxide nanoparticles: a green chemistry approach

A comparative study of Solanum trilobatum-mediated magnesium oxide (St-MgO) nanoparticles (NPs) and sodium hydroxide-mediated MgO (Che-MgO) NPs are synthesized using magnesium nitrate precursor. The characterization analyses, such as ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy-dispersive X-ray diffraction (EDX), scanning electron microscopy (SEM) and particle-size analysis were carried out. To determine the antioxidant activity of MgO NPs by 2,2-diphenyl-1-picrylhydrazyl (DPPH) method and antibacterial activity against Escherichia coli (MTCC: 912), Bacillus subtilis (MTCC: 121) and Streptococcus pyogenes (MTCC: 1925), was performed by the well-diffusion method. The UV-Vis analysis of St-MgO, Che-MgO confirmed the formation of MgO NPs that have a broad absorption peak at 362 and 374nm, respectively. IR spectrum of synthesized St-MgO and Che-MgO exhibits a high-intensity band at 440 and 460 cm-1, respectively. XRD analysis indicates that synthesized St-MgO, Che-MgO were crystal in nature and EDX confirmed the composition of MgO-NPs. SEM analysis revealed that St-MgO and Che-MgO NPs were spherical in shape without aggregation. Particle-size analysis confirmed that the average particle sizes of St-MgO and Che-MgO NPs were 30 and 42 nm, respectively. DPPH assay of St-MgO NPs has higher absorbance value, which indicates the high antioxidant capacity compared with ascorbic acid. St-MgO NPs are effective against bacterial pathogens, such as E. coli (16.66 +/- 0.66), B. subtilis (16.00 +/- 0.88) and S. pyogenes (13.66 +/- 2.08) at 100 mg ml-1 concentration when compared with Che-MgO and the control (P<0.001). Thus, the result suggested that safer use of biologically synthesized MgO NPs can act as effective antioxidant and antibacterial agents in the field of biomedicine.