Table 3.
In vitro antibacterial activities of the essential oils (EOs) of Salvia officinalis and Mentha suaveolens via the disc-diffusion method. Chloramphenicol and DMSO were used as a positive and negative control, respectively.
| S. officinalis EO (10 μl/disc) | M. suaveolens EO (10 μl/disc) | Chloramphenicol (30 μg/disc) | 10% DMSO (10 μl/disc) | |
|---|---|---|---|---|
| Gram-positive bacteria | ||||
| Staphylococcus aureus | 28.0 ± 0.6 | 31.6 ± 0.6a | 30.8 ± 0.6 | — |
| Staphylococcus epidermidis | 25.1 ± 0.5 | 27.5 ± 0.3a | 28.7 ± 0.3 | — |
| Enterococcus faecalis | 20.2 ± 0.4 | 22.7 ± 0.4a | 23.4 ± 0.3 | — |
| Listeria monocytogenes | 25.0 ± 0.3 | 29.6 ± 0.4a | 27.5 ± 0.2 | — |
| Bacillus cereus | 26.8 ± 0.4 | 30.4 ± 0.3a | 29.0 ± 0.2 | — |
|
| ||||
| Gram-negative bacteria | ||||
| Escherichia coli | 18.6 ± 0.3 | 21.7 ± 0.2a | 28.1 ± 0.3 | — |
| Salmonella typhimurium | 16.3 ± 0.2 | 18.7 ± 0.1a,b | 21.0 ± 0.3 | — |
| Klebsiella pneumoniae | 17.6 ± 0.2 | 19.4 ± 0.2a,b | 23.1 ± 0.2 | — |
| Proteus mirabilis | 17.1 ± 0.3 | 21.3 ± 0.1a,b | 25.3 ± 0.5 | — |
| Pseudomonas aeruginosa | 8.1 ± 0.5b | 9.2 ± 0.1b | — | — |
Values are the mean zone of inhibition (mm) ± SD. (–), undetected activity. a,bP < 0.05 vs. S. officinalis EO and chloramphenicol, respectively.