Chemical Characterization and Biological Potential of the Essential Oil of Eucalyptus globulus Labill

Oxidation of lipids in various products, along with the growth of medically important pathogens, has led to a search for medicinal plants with antioxidant and antimicrobial activities. As a result, the aim of this study was to evaluate the antioxidant and antibacterial activity of the essential oil of Eucalyptus globulus (EO-Eg). Antioxidant activity was assessed by using the 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) assay method. Existing components were identified through gas chromatography-mass spectrometry (GC-MS) analysis. Antibacterial activity and minimum inhibitory concentration (MIC) were assessed by using the broth microdilution method with standard multidrug-resistant bacterial strains. The main EO-Eg compounds identified by GC-MS were isopulegol, citronellal, and citronellol, which are primarily used in the industrial sectors. EO-Eg demonstrated excellent antioxidant activity with an effective concentration (EC50) of 4.48 μL/mL owing to the presence of phenolic compounds. Regarding antibacterial activity, the EO-Eg displayed a broad antimicrobial spectrum of antimicrobial activity across the different resistance phenotypes analyzed. The most notable antibacterial activity was observed against Staphylococcus aureus 169 MRSA (MIC = 0.0625%). As a result, our findings suggest that EO-Eg has antioxidant and antibacterial potential against hospital-acquired multidrug-resistant pathogens, which may be correlated with its major components.