Antibacterial activity of essential oils from Eucalyptus camaldulensis Dehn. and Eucalyptus tetragona F.Muell

Abstract

IntroductionEucalyptus plants are used as a source of essential oils in Ethiopia and are traditionally used for the treatment of the common cold, stomachache, swelling and wounds. This study aims to determine the chemical composition and antibacterial activity of the essential oils of E. camaldulensis Dehn. and E. tetragona Muell. MethodologyThe chemical composition of the essential oils of E. camaldulensis Dehn. and E. tetragona F.Muell. was determined using gas chromatographymass spectrometry (GCMS), and their antibacterial activity of was evaluated against E. coli ATCC 25922 and S. ATCC 25923. ResultsThe yield of essential oil from the leaves of E. camaldulensis was 0.72% w/w, and the yield of essential oil from the leaves of E. tetragona was 0.80% w/w on the basis of fresh leaf weight. A total of 17 and 14 components were identified in E. camaldulensis and E. tetragona, respectively. The main components identified were 1,8-cineole, β-cymene and α–pinene in both Eucalyptus species analysed. The extracted essential oils displayed moderate to strong antibacterial activity. E. tetragona inhibited S. aureus at a lower concentration (0.625 μg/ml), while E. coli was less sensitive to the EOs of E. camaldulensis, with an MIC of 2.5 μg/ml. ConclusionThe essential oils of E. camaldulensis and E. tetragona exhibited significant antibacterial activity against E. coli and S. aureus. The results showed that the essential oils of E. camaldulensis and E. tetragona may be useful for treating various infectious diseases. Essential oils, particularly 1,8-cineole, can be used as alternative natural antimicrobial agents in the pharmaceutical and food industries.