Chemical Composition, Antimicrobial and Antioxidant Activities of Essential Oils of Four Species of the Lamiaceae Family

Aims: The biological properties of essential oils represent possible therapeutic alternatives, with antimicrobial and antioxidant activities, and application in many areas of the industry. The objective was to determine the yield, chemical composition, antibacterial and antioxidant activities of the essential oils of Lavandula angustifolia, Pogostemon cablin, Rosmarinus officinalis, and Thymus vulgaris against Staphylococcus aureus, Salmonella enteritidis, Escherichia coli and Pseudomonas aeruginosa.

Place and Duration of Study: The experiment was conducted at the microbiology laboratory of the Federal University of Technology - Paraná, Brazil, in the period between June 2016 to May 2017.

Methodology: The essential oils were analyzed by gas chromatography coupled to mass spectrometry. The antibacterial activity was determined by microdilution in broth, showing minimum inhibitory concentration and minimum bactericidal concentration. The antioxidant activity was evaluated by scavenging of 2,2-diphenyl-1-picryl hydrazyl radical (DPPH).

Results: The average yields of essential oils from L. angustifolia, P. cablin, R. officinalis,and T. vulgaris were (%) 0.85; 2.0; 1.20, and 1.19, respectively. The major components of lavender essential oil were linalyl acetate (40.1%) and linalool (35.2%); for P. cablin - patchoulol (31.5%), seichelene (13.6%) and α-bulnesene (15.6%); for rosemary - camphor (32.5%), 1.8-cineole (13.6%) and α-pinene (9.8); for T. vulgaris - thymol (47%), o-scimene (21.6%), and carvacrol (11.4%). Thyme oil showed the best results for antibacterial activity, and low values (0.195 µL mL-1) of minimum inhibitory concentration were needed to inhibit S. aureus and S. enteritidis, and for L. angustifolia, P. cablin, and R. officinalis higher concentrations of essential oil were required. The essential oils of P. cablin and T. vulgaris had the strongest antioxidant properties (12.08 and 10.2 µmol trolox mL−1).

Conclusion: The essential oils evaluated have an inhibitory effect on the microorganisms under study and also interesting antioxidant activity, which could be used by medicine to control bacterial infections, with potential application as natural food preservatives and as nutraceuticals.