Antimicrobial Activity of Eucalyptus (Eucalyptus camaldulensis) Essential Oil Against Fish Pathogen Bacterium, Aeromonas caviae

Abstract

The intensive use of antibiotics in aquaculture has resulted in increased resistance among fish pathogens, and this situation has led researchers to investigate the antibacterial properties of natural resources. The present study focused on an essential oil isolated from the leaves of Eucalyptus camaldulensis as a potential antibacterial that could be used against Aeromonas caviae. Eighteen compounds were identified in the essential oil, representing 86.68 % of the total oil. The components were found to be p-cymene (20.09%), β-phellandrene (18.61%), α-phellandrene (7.50%), α-terpineol (6.02%), terpinen-4-ol (5.50%), Crypton (5.36%), spathulenol (4.26%), linalool (3.56%), 1,8-cineole (2.77%), farnesol (2.31%), Cumin aldehyde (2.13%), limonen (2.12%), α-thujene (1.94%), fellendral (1.13%), γ-terpinene (1.10%), sabinene (0.97%), α-pinene (0.68%) and α-terpinen (0.63%). The antibacterial efficiency of essential oils against Aeromonas caviae was determined using Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values, ranging from 200 µg/ml to 400 µg/ml respectively. Our findings revealed the potential of essential oils isolated from Eucalyptus (Eucalyptus camaldulensis) as a natural antibacterial agent that could efficiently contribute to the control of Aeromonas caviae infection in fish.