Antibacterial and antioxidant activities of essential oils isolated from Origanum spp and Calamintha baetica

Aims: Staphylococcus aureus and Bacillus cereus are two Gram positive foodborne pathogens and the use of essential oils isolated from aromatic plants can constitute a natural and equally effective to other chemicals agents in the control of these pathogens avoiding the development of antibacterial resistance. The essential oils can also constitute a good alternative to the synthetic antioxidants, generally used in food industry, but without the adverse effects described for this kind of compounds. Methods: The oils were isolated by hydrodistillation and analysed by gas chromatography and gas chromatography coupled to mass spectra. The antibacterial activity of essential oils of Origanum spp and Calamintha baetica was tested against four strains of St. aureus and three strains of Bacillus cereus using the disc agar diffusion technique. Chloramphenicol and water were used as positive and negative control, respectively. The antioxidant activity was evaluated by two different spectrophotometric methods. Results: The main components of Origanum spp. and C. baetica were γ-terpinene and isopulegone, respectively. The Calamintha essential oi