Bioactivity of Essential Oils of Species of the Lamiaceae Family

Abstract

The Lamiaceae family is composed of important medicinal, aromatic, and condiment plants used in various areas of traditional and modern medicine. Essential oils' biological qualities indicate potential medicinal options, including antibacterial and antioxidant capabilities and applications in a variety of industries.  The goal 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. The experiment was conducted at the microbiology laboratory of the Federal University of Technology - Paraná, Brazil. Gas chromatography combined with mass spectrometry was used to examine the essential oils. Microdilution in broth was used to test antibacterial activity, revealing the minimal inhibitory and bactericidal concentrations. The antioxidant activity was evaluated by scavenging of 2,2-diphenyl-1-picryl hydrazyl radical (DPPH). 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%); P. cablin - patchoulol (31.5%), seichelene (13.6%) and \(\alpha\)-bulnesene (15.6%); rosemary - camphor (32.5%), 1.8-cineole (13.6%) and \(\alpha\)-pinene (9.8); 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 \(\mu\)L mL^-1) of minimum inhibitory concentration were required to inhibit S. aureus and S. enteritidis, which indicates high bioactivity of this oil, due to phenolic compounds that are active against many microorganisms. We observed that high concentrations of essential oil from L. angustifolia, P. cablin, and R. officinalis were necessary to inhibit the bacteria evaluated. The essential oils of P. cablin and T. vulgaris have the highest antioxidant activity (12.08 and 10.2 \(\mu\)mol trolox mL^-1) respectively. The essential oils studied had an inhibitory effect on the microorganisms under investigation, as well as intriguing antioxidant activity, which might be exploited by medicine to manage bacterial infections, with potential applications as natural food preservatives and nutraceuticals.