Abstract
► Ten chemotypes were identified. ► E. cinerea was the richest species in 1,8-cineole and E. odorata was the richest species in cryptone. ► E. odorata was the most active against Staphylococcus aureus. ► Antibacterial activity was correlated with 1,8-cineole, p-cymene, α-pinene, or cryptone amount.
The essential oils of twenty Eucalyptus species harvested from Zerniza and Souinet arboreta (North West and North of Tunisia), were screened for their antibacterial activities by the agar disc diffusion method. Eighteen major compounds, identified by GC and GC/MS, have been retained for the study of the chemical and biological activity variability. The main ones were 1,8-cineole followed by α-pinene, p-cymene, borneol, cryptone, spathulenol, viridiflorol and limonene. The chemical principal components analysis identified 10 chemotypes, however that of the inhibition zone diameter (izd) of growth bacteria separated 5 groups of Eucalyptus oils, characterised by their antibacterial inhibition ability. The most sensitive strain was the Gram positive Staphylococcus aureus with that of E. odorata oil (16.0±1.0mm izd), while the most resistant bacteria was Pseudomonas aeruginosa. Some correlation between the amount of 1,8-cineole, p-cymene, α-pinene, or of cryptone and the antibacterial activity were observed.