Antibacterial activities of the essential oil and hydroethanolic extract from Aeollanthus heliotropioides Oliv

To control bacterial infections, we proposed evaluating the antibacterial activities and modes of action of Aeollanthus heliotropioides essential oil and its hydroethanolic extract. Solvent extracts and essential oil were obtained from the aromatic plant's aerial parts by hydroethanolic maceration and hydro-distillation. The analyses of the chemical composition were performed using gas chromatography coupled with mass spectrometry. The microdilution method evaluated the in vitro antibacterial potential of the essential oil and solvent extracts . The Inhibition of biofilms formation was carried out using a colorimetric biofilm microdilution assay with crystal violet as a dye. The effect of extract and essential oil on the release of nucleic acids was performed using a spectrophotometric method. The time-kill kinetic assay was assessed for hydroethanolic extracts and essential oil. The extraction yield was 0.1%, and the major compounds identified in the essential oil were linalool (43.47%) and cis-α-farnesene (42.67%). The phytochemical screening revealed flavonoids, saponins, phenols, triterpenes, catechin tannins, and quinones. Minimum Inhibitory Concentrations (MICs) ranged from 2.08 mg/mL to 10 mg/mL. Concerning the modes of action, the essential oil showed its bactericidal effect at 2 hours. The reduction of Escherichia coli biofilms formation was found at 0.21 mg/mL. The essential oil treatments resulted in a release of nucleic acids at a concentration of 2.1 mg/mL. These results justify using the essential oil and hydroethanolic extracts of Aeollanthus heliotropioides as a potential source of molecules with antibacterial activity.