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

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%), βphellandrene (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.