Antimicrobial and Antioxidant Activities of Four Essential Oils

Various opportunistic microorganisms, such as bacteria and fungi, are responsible for multiple infectious diseases, which represent a threat to global health. Essential oils (EOs) have shown antimicrobial and antioxidant properties, making them an excellent alternative to control multi-resistant bacteria. In this work, for the first time, the antimicrobial and antioxidant activities of four EOs were evaluated, namely Trixis angustifolia DC (EOTA), Dalea bicolor Humb & Bonpl. Ex Willd (EODB), Tagetes parryi A.Gray (EOTP) and Eupatorium glabratum Kunth (EOEG). They were obtained by hydrodistillation, and their chemical composition was determined by GC-MS (Gas chromatography-mass spectroscopy) using HP5-MS column. Their antimicrobial and antioxidant activities were determined by the microdilution method and the DPPH and ABTS techniques, respectively. The main compounds of the EOs were piperitone (36.67 %25) for EOTA, β-pinene (27.25) for EODB, verbenone (31.13 %25) for EOTP and α-cadinol (7.78 %25) and bornyl acetate (6.45 %25) for EOEG. The EOs EOTA, EODB, EOTP and EOEG inhibited the development of Candida at a concentration of 62.5–500 µg/mL, whereas the antibacterial activities of these oils were observed at concentrations from 125–500 µg/mL. The antioxidant activity of EOTA and EODB were IC50 = 0.641, 1.195 mg/mL, whereas those of EOTP and EOEG was lower. These results show that four EOs have antimicrobial activity.

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