Phytochemical profile and antilisterial activity of Salvia officinalis Supercritical Fluid Extract

• Supercritical fluid extraction was used to obtain phytochemicals from sage. • The bioactive compounds from S45 fraction disturb the Listeria spp. intracellular function. • The bioactive compounds appeared to affect the L. monocytogenes membrane permeability. • Docking tests suggested that fatty acids interfere with Listeria virulence expression. In this study, the natural compounds obtained from supercritical fluid extraction of sage ( Salvia officinalis ) were tested for their ability to affect the cells’ integrity and virulence of pathogenic Listeria monocytogenes ScottA . The extract collected from separator S45 exhibited greater antibacterial potential compared to that from separator S40, featuring a more complex phytochemical profile with elevated levels of polyphenols, carotenoids, and fatty acids. The major fatty acid detected in the fraction S45 included nonanoic, undecanoic, linolenic, and palmitic acid. The Minimal Inhibitory Concentration (MIC) determined through microdilution assay, was found to be 0.39 mg/mL. The growth curve kinetics of L. monocytogenes in the presence of fraction S45 revealed a significant difference between lag and exponential phase for the control and the cells treated with MIC and sub-inhibitory concentration. Scanning electron micrographs displayed less translucent, highly distorted, partially disintegrated, and damaged cellular aggregation in the treated bacterial cells. Furthermore, the evaluation of cytoplasmic membrane leakage at 260 nm indicated that significant cell membrane disruption occurred after treatment with 2xMIC of fraction S45. Additionally, SDS-PAGE results suggested that the bioactive compounds from S45 fraction interfered with protein synthesis. A reduction in genomic DNA yield, along with faint DNA bands in agarose gel electrophoresis were observed. Molecular docking tests using the Transcriptional Regulator PrfA as the receptor indicated that the production of the virulence factor in L. monocytogenes may be affected by the main free fatty acids found in the sage extract.