Micromeria barbata for targeting MRSA virulence: In silico and in vitro studies

The present study reports the characterization of the phytochemical content and the antibacterial activity of ethanolic extracts from the leaves (LE) and stems (SE) of Micromeria barbata (M.barbata) against Methicillin resistant Staphylococcus aureus (MRSA). Important functional groups were determined by analyzing the FTIR spectra of LE and SE. The phytochemical profiles were analyzed by GC-MS, and these characterized the chemicals according to retention periods and peak regions. The binding affinities of discovered compounds with the MRSA SarA and CrtM proteins were evaluated using molecular docking approach. Assays for biofilm formation, MIC, MBC, and agar well diffusion were used to assess the antimicrobial activity. From the FTIR spectra, hydroxyl group alkanes, amides, and aromatic constituents were identified. Nine distinct substances were obtained from GC-MS analysis;, including piperitenone cyclohexene, palmitic acid, safranal, and oleic acid in SE, and iso-menthone, oleic acid, 1-pentanol, kumarone, and benzene in LE. Stronger binding affinities between LE compounds and the SarA protein were obtained from molecular docking with ΔG values ranged from -10.9 to -11.6 were higher compared to SE compounds. Antimicrobial findings showed that SE and LE exhibited an antimicrobial effect against S. aureus with 15 and 20 mm respectively as inhibition zones. MIC values for LE and SE were 6.25 mg/ml and 12.5 mg/ml, respectively. With LE showing greater effectiveness, both extracts exhibited concentration-dependent reduction of biofilm formation and bactericidal activity. Extracts of M. barbata, notably the leaves, have significant antibacterial activity against S. aureus, suggesting potential applications in the developing of novel antibacterial treatments.