Integrative chemical profiling combined with molecular docking, molecular dynamics simulations, ADMET, and DFT analysis reveal the anti-infective and antioxidant potential of Pulicaria incisa (Lam.) DC. essential oil supported by experimental validation.

The discovery of novel anti-infective agents through integrated in vitro and in silico approaches is crucial to combat the increasing global burden of infectious diseases. Accordingly, this study aimed to investigate the antimicrobial (ESKAPE pathogens and fish/shellfish pathogens), antibiofilm, and anti-quorum sensing (anti-QS) activities of P. incisa essential oil (P. incisa EO), supported by integrated computational analyses. GC/MS (Gas chromatography/ mass spectrometry) analysis revealed the presence of oxygenated monoterpenes (85.7%) and identified forty-two components dominated by limonene oxide (37.8%), followed by 1(7)-p-menthene-2-one (12.87%), 2,3,6-trimethylanisole (10.85) and filifolone (10.78%). The volatile oil of P. incisa showed strong antimicrobial and anti-virulence activity, with MICs value as low as 0.39 µg/mL and MBC of 12.5 µg/mL against Vibrio alginolyticus. In addition, P. incisa EO inhibited biofilm formation by more than 75% in Staphylococcus aureus, Bacillus subtilis, and Candida albicans at MIC level, and strongly affected QS regulated factors, showing 100% violacein inhibition by Chromobacterium violaceum CV026 at 0.025 µL/mL and 73.91 ± 1.19% swarming motility of PAO1 strain at 100 µL/mL. Moreover, P. incisa EO also reduced pyocyanin production in P. aeruginosa in a dose-dependent manner (63.30% at 2.5 µL/m), 47.60% at 1.25 µL/mL, and 35.40% at 0.625 µL/mL. The antioxidant potential of the examined EO was demonstrated through DPPH and β-carotene bleaching assays, showing IC₅₀ values of 0.476 ± 0.0081 and 0.111 ± 0.0083 mg/mL, respectively. While less active than ascorbic acid in radical scavenging, the oil exhibited promising lipid peroxidation inhibition capacity. Furthermore, molecular docking analysis showed stable binding of all phytocompounds to the selected targets, with favorable interaction patterns. 1-Phenylbut-2-ene (-7.7 kcal/mol) and piperitenone (-8.7 kcal/mol) exhibited the strongest predicted binding affinities and stable interactions, which were further assessed by 100 ns molecular dynamics (MD) simulations. The combined docking, MD, DFT, and ADMET results support these compounds as prioritized leads for subsequent experimental studies. Further clinical validation is required to confirm the pharmacological potential of this oil and its main components.