Bioactive Potential of Pistacia terebinthus L. From the Atlas of Morrocco: Antioxidant and Antimicrobial Properties

Pistacia terebinthus L., a tree native to the Middle Atlas of Morocco, is traditionally used in folk medicine. This study investigated the phytochemical profile, antioxidant, and antimicrobial properties of leaf essential oils (EOs) from three bioclimatic zones. EOs were extracted by hydrodistillation, analyzed by GC–MS, and tested for antioxidant activity using FRAP and DPPH assays. Molecular docking was performed to assess the interaction of major compounds with antioxidant targets, while antimicrobial activity was evaluated against bacterial and fungal strains by disk diffusion and microdilution. The chemical composition varied markedly among regions, with 61–98 compounds identified. Monoterpenes, particularly α-pinene, were abundant in arid samples, whereas terpinen-4-ol (21.96%) appeared exclusively in subhumid oils. Other relevant constituents included τ-muurolol (8.84%) and D-limonene (7.85%). Antioxidant activity also differed by origin, with IC50 values ranging from 1.40 to 4.17 mg/mL and EC50 from 2.86 to 9.47 mg/mL. Subhumid oils exhibited the highest antimicrobial activity, while arid samples were most effective against Staphylococcus aureus. Docking analysis revealed interactions of key compounds with NADPH oxidase (Ala11, Asp282, Ala300), suggesting a potential mechanism for their antioxidant action. Overall, results highlight that bioclimatic conditions strongly influence the chemical composition and bioactivity of P. terebinthus essential oils, supporting their potential for therapeutic and pharmaceutical applications.