Antimicrobial activity and phytochemical composition of oregano, peppermint, thyme, and lavender essential oils

Abstract

This summary of research results describes three important experiments in which the antibacterial properties and composition of essential oils of four different plants (oregano, peppermint, thyme, and lavender) were studied. First, it was found that the essential oil of oregano has significant antibacterial effects on all the tested bacterial cultures, despite its concentration being only 5%. It was also found that the essential oils of thyme and peppermint are more effective against certain Gram bacterial cultures. However, the true essential oil of lavender, used at a concentration of 10%, was only able to suppress the growth of certain Gram+ bacteria. Secondly, using gas chromatography mass spectrometry, components that contribute to the antibacterial effect of each plant's essential oil were identified. Carvacrol was found in oregano, linalool in thyme, menthol in peppermint, and linalool in lavender. Thirdly, the dominant components in each plant's essential oils were quantitatively evaluated during the study. In common thyme (Thymus serpyllum L.), linalool was found to be 0.541 ± 0.09 mg/ml, in common oregano (Origanum vulgare L.), carvacrol was 0.742 ± 0.05 mg/ml, in peppermint (Mentha piperita L.), menthol was 0.725 ± 0.11 mg/ml, and in true lavender (Lavandula angustifolia L.), linalool was found to be 0.581 ± 0.05 mg/ml. These research results can be useful for further studies on the mechanisms of plant antibacterial activity and their potential application in medicine or other industrial sectors