Zeinab Chaghakaboodi - Department of Production Engineering and Plant Genetics, Faculty of Science and Agricultural Engineering, Razi University, Kermanshah, Iran
Danial Kahrizi - Department of Agricultural Biotechnology, Tarbiat Modares University, Tehran. Iran.
Jaber Nasiri - Nuclear Agriculture Research School, Nuclear Science and Technology Research Institute, AEOI, Karaj, Iran.

Here, to assess the chemical composition and antibacterial/antioxidant effects of the essential oils of eucalyptus, the young leaves of eucalyptus trees (Eucalyptus camaldulensis) cultivated in Shushtar city (Khuzestan Province, Iran) were utilized in the late spring season of ۲۰۲۴. The essential oil extraction was carried out using the water distillation method, resulting in a ۲% yield based on the dry weight of the leaves. Gas chromatography-mass spectrometry (GC-MS) analysis of the essential oil indicated the presence of (S,E)-۲,۵-Dimethyl-۴-vinylhexa-۲,۵-dien-۱-yl acetate, alpha-terpinene, and (-)-Globulol as the major components, accounting for ۱۷.۶۳%, ۹.۹۷%, and ۶.۲۳% of the total composition, respectively. Further DPPH assay testing showed a concentration-dependent inhibitory effect, with the highest concentration (۰.۸۰ mg/ml) exhibiting an impressive ۹۳.۶۲% inhibition. According to the ANOVA results, a significant difference was observed among all nine treatments (multiplying by three different essential oil concentrations of ۰.۲, ۰.۴, and ۰.۸ mg/mL and three different bacterial agents of S. aureus, B. cereus, and E. coli) in terms of inhibition zone recorded using the agar well diffusion method. The largest inhibition zones were observed for three treatments of "۰.۸ mg/mL + B. cereus", "۰.۴ mg/mL + S. aureus", and "۰.۸ mg/mL + S. aureus" with the inhibition zone values of ۳۹.۶۲ mm, ۳۵.۳۷ mm, and ۳۹.۱۱ mm, respectively. On the other hand, the minimum inhibition zone value of ۱۴.۰۲ mm was observed for the "۰.۲ mg/mL + E. coli" treatment. According to the results, both gram-positive bacteria of S. aureus and S. cereus were more sensitive to the essential oil of E. camaldulensis essential oil than the gram-negative bacteria of E. coli. These current promising results demonstrated the effectiveness of E. camaldulensis essential oil as a natural and eco-friendly alternative for antimicrobial studies.

Antioxidant activity, Antibacterial activity, essential oil, Eucalyptus camaldulensis