Chemical analysis and antibacterial activity of optimized Satureja montana L. extracts

The study aimed at the phytochemical characterization of the optimized ethanol and acetone extracts of Satureja montana L., and the evaluation of their antibacterial and synergistic activity with an antibiotic, along with their potential mechanisms of action. Response surface methodology was employed to optimize the extraction conditions. The antibacterial activity was evaluated using microdilution, checkerboard, time-kill kinetics, and cell membrane permeability methods. S. montana extracts were effective against different bacterial species, including the Gram-positive Staphylococcus aureus, Enterococcus sp., Bacillus cereus, and the Gram-negative Acinetobacter sp. and Proteus mirabilis. Notably, the acetone extract enhanced gentamicin's efficacy up to 16-fold against a gentamicin-resistant strain of P. mirabilis. Additionally, the extracts exhibited bactericidal activity against certain strains within a 3-hour and 6-hour time frame and increased cell membrane permeability, thereby disrupting normal cellular functions. The ethanol and acetone extracts reached a total phenolic content of 79.44 ± 0.5 mg GAE/g and 53.88 ± 0.2 mg GAE/g, and a total flavonoid content of 27.93 ± 0.3 mg RUE/g and 16.35 ± 0.3 mg RUE/g, respectively. Rosmarinic acid, chlorogenic acid, luteolin, quercetin, and naringenin were detected in the highest quantities in the extracts. S. montana extracts may serve as potential natural antibacterial agents.