The Antibacterial and Antioxidant Effects of Clove (Syzygium aromaticum) and Lemon Verbena (Aloysia citriodora) Essential Oils

Background: The study aimed to investigate the chemical composition, antimicrobial effects, and antioxidant properties of clove and lemon verbena essential oils (EOs). Methods: The chemical composition of the EOs was identified using gas chromatography/mass spectrometry (GC/MS). In addition, the antibacterial effects of EOs against seven important foodborne bacteria were assessed using the disk-diffusion, agar well-diffusion, and broth microdilution assays. Evaluation of the antioxidant properties of the EOs was carried out using DPPH, β-carotene-linoleic acid bleaching, and reducing power assay. Results: All the tested bacteria demonstrated susceptibility to EOs, with the highest susceptibility observed in Bacillus cereus to the clove EO in the agar disk-diffusion test. Moreover, Shigella dysenteriae was identified as the most sensitive bacterium to the lemon verbena EO. Salmonella typhimurium was the most resistant bacterium to both EOs. In the agar well-diffusion test, Pseudomonas aeruginosa and S. typhimurium had the lowest sensitivity to the clove and lemon verbena EOs, respectively. Although both EOs exhibited significant antioxidant capacity, the lemon verbena EO showed higher antioxidant activity in all the tests, with the exception of β-carotene-linoleic acid bleaching test. Conclusion: Clove and lemon verbena EOs could be regarded as potential sources of natural antioxidant and antimicrobial agents in food processing.