Comparative analysis of chemical composition and antibacterial activity of essential oils from different parts of Moroccan Pistacia atlantica; in silico ADME/tox, molecular docking and molecular dynamics studies

The aim of the present study is to investigate the chemical composition of Pistacia atlantica Desf. essential oils (EOs) derived from leaves, fruits, and branches. Along with the assessment of their antibacterial potential against selected pathogens. Further Molecular docking was performed to investigate the binding affinity between selected bacterial protein targets and EO components. EOs were analyzed using gas chromatography–mass spectrometry (GC-MS), revealing variable chemical profiles across the three parts: terpinen-4-ol (23.20%) and spathulenol (12.24%) were predominant in the leaf EO; trans-β-ocimene (22.54 %) and α-pinene (19.62%) in the fruit EO; and n-hexadecanoic acid (12.92%) and α-phellandren-8-ol (9.95%) in the branch EO. Notably, this study reports, for the first time, the chemical characterization and antibacterial activity of essential oil extracted from the branches of P. atlantica, showing antibacterial activity against Staphylococcus aureus and Escherichia coli (MIC = 0.78 and 6.25 mg/mL, respectively). Among EOs components, molecular docking revealed strong binding affinity of γ-muurolene toward all bacterial targets, and moderate-to-strong interactions of germacrene D, terpinen-4-ol, and α-terpinyl acetate with at least two bacterial proteins. Molecular dynamics further revealed stable interactions of γ-muurolene across multiple bacterial targets mediated by hydrophobic interactions. In addition, γ-muurolene exhibited favorable predicted drug-likeness and ADMET profiles, including good lipophilicity, oral bioavailability, and low toxicity. Overall, these findings support the valorization of P. atlantica branches as a potential source of bioactive compounds and identify γ-muurolene as a promising antibacterial scaffold for further experimental investigation.