Essential oils can be used in a variety of ways to treat microorganisms that have evolved antibiotic resistance. The research assessed the antimicrobial and antioxidant activities of essential oil obtained from Citrus Limonum, Citrus reticulate, and Citrus sinensis fresh peels using the hydro-distillation method. Their chemical compositions were analyzed by Gas Chromatography-Mass Spectrometer. Citrus oils had antimicrobial and antioxidant properties and their activity was increased with increasing concentrations. Oils had a significant antimicrobial effect on tested bacteria except on P. aeruginosa only C. Limonum had significant (p≤0.05) inhibitory effects at both 100 and 200 mg/ml. There was no significant (p>0.05) difference in the inhibition zone of tested oils against A. baumannii and ciprofloxacin at 25 mg/ml, which was the same as against E. coli at 200 mg/ml. The oil inhibitory effect on K. pneumoniae, P. mirabilis, and S. aureus was less than that obtained from ciprofloxacin at concentrations used.  At 100 mg/mL, C. reticulate oil had a 23 mm inhibitory zone, while C. sinensis oil had a 23 mm inhibitory zone at 200 mg/mL, which was the same as the inhibitory area of ciprofloxacin against S. marcescens. Oils had convergent antifungal activity against Candida albicans that increased with increasing concentrations. The extracts competed favorably with voriconazole being used as a positive control. Citrus oils had convergent scavenging activities at the concentrations used. The studies confirmed the medicinal and industrial use of citrus essential oils as a therapeutic and antioxidant agent.

Keywords: citrus essential oils; antibacterial; antifungal; DPPH