Solenanthus tubiflorus Murb. essential oil: phytochemical analysis, antibacterial activity with mechanistic investigation through scanning electron microscopy and in silico docking studies.

The essential oil (EO) extracted from fresh flowers of Solenanthus tubiflorus Murb. growing in Tunisia was analysed by GC/MS and its chemical composition was reported for the first time. Seventy-two compounds were identified, with 3-carene (19.57%), estragole (17.75%), bicyclo[3.1.0]hexane, 4-methylene-1-(1-methylethyl)- (7.32%), and α-terpinyl acetate (6.13%) as the major constituents. The antibacterial activity of the EO was evaluated against five bacterial strains using the microbroth dilution assay. It showed notable activity, particularly against Gram-positive bacteria, with a minimum inhibitory concentration (MIC) of 1% (v/v). The antibacterial mechanism of the essential oil against S. aureus was investigated by scanning electron microscopy (SEM), which revealed severe morphological alterations including membrane disruption, cell deformation, and cytoplasmic leakage. Moreover, molecular docking of the main compounds with the acylated penicillin-binding protein 2a from methicillin-resistant S. aureus (PDB: 1MWT) demonstrated promising interactions. These findings highlight the potential of Solenanthus tubiflorus Murb. EO as a natural antibacterial agent.