Antioxidant and antibacterial activities of essential oils and aromatic waters of some plants grown in the highlands

The essential oils from twenty-two plants grown in the highlands were isolated by hydrodistillation. The plants with an essential oil yield above one percent, including Achillea millefolium, Asparagus plumosus, Matricaria chamomilla, Mentha piperita, Mentha pulegium, and Thymus vulgaris, were tested for the antibacterial activity and total antioxidant capacity. Their antibacterial activities against three most common foodborne pathogens and an opportunistic pathogen were evaluated. Results indicated that T. vulgaris essential oil had the highest total antioxidant capacity with 11.78 ± 0.01 mmol/L TE. The essential oils of plants inhibited the growth of pathogen bacteria tested, while their aromatic waters showed no inhibition. T. vulgaris oil was most powerful antibacterial essential oil with the inhibition zones of 49.27±7.26 mm against S. aureus, 44.13±4.16 mm against L. monocytogenes, 39.55 ± 0.52 mm against E. coli, and 38.09 ± 4.15 mm against M. luteus. Furthermore, the volatile compounds of T. vulgaris essential oil were detected using GC-MS. Thymol, carvacrol, caryophyllene, 1,8-cineole, 2 acetyl-4,5-dimethylphenol, and γ-terpinene were determined as major compounds in T. vulgaris essential oil. The obtained results suggest that the essential oils of tested plants with high antimicrobial activity and antioxidant capacity might be used as natural antioxidant and antimicrobial agents.