Eucalyptol from Rosmarinus officinalis L. as an Antioxidant and Antibacterial Agent against Poultry-Isolated Bacterial Strains: in Vitro and in Silico Study

This research aimed to analyze the chemical composition of Rosmarinus officinalis L. essential oil collected from Morocco using GC/MS. The primary compound of EO was further isolated and purified to evaluate its antibacterial activity and antioxidant effects. The results showed that eucalyptol was the major compound of the EO, representing 34.06%. The EO exhibited an IC₅₀ of 3.23 mg/ml through the DPPH assay, whereas eucalyptol displayed no antiradical activity. In comparison, the molybdate assay revealed an EC₅₀ of 0.23 mg/ml and 0.58 mg/ml, respectively. EO and eucalyptol exhibited antibacterial activity against all tested strains (E. coli and Salmonella). The MIC ranged from 0.35 to 11.37 mg/ml for eucalyptol and 5.68 to 45.50 mg/ml for EO. Furthermore, the molecular docking scores of eucalyptol and the amino acids of various proteins of E. coli and Salmonella were investigated, and the results demonstrated strong interactions between eucalyptol and the proteins of the bacteria.