Volatile Compounds from Northern Moroccan Medicinal Plants: Phytochemical Analysis, Antioxidant and Antimicrobial Potential, and In Silico Investigations

Abstract

Essential oils (EOs) from aromatic plants are valuable sources of bioactive compounds with potential applications as natural antimicrobials and antioxidants. This study investigated the chemical composition, antimicrobial and antioxidant activities, and in silico pharmacological properties of EOs extracted from Laurus nobilis, Thymbra capitata, and Mentha piperita, three medicinal species traditionally used in northern Morocco. Hydrodistillation yielded 1.12–1.53% oils, and GC–MS analysis revealed distinct chemotypes: L. nobilis was rich in eucalyptol, linalool, methyleugenol, and α-terpinyl acetate; T. capitata was dominated by carvacrol (80.95%), and M. piperita contained high proportions of linalool (57.37%) and linalyl acetate (28.56%). Antimicrobial assays demonstrated strong activity of all oils against Gram-positive and Gram-negative bacteria as well as Candida species, with T. capitata showing the most potent and broad-spectrum effects (MIC 0.073–9.47 mg/mL), attributed to its high carvacrol content. Antioxidant assays (DPPH and ferric reducing power) identified L. nobilis as the most active radical scavenger (IC50 = 0.037 mg/mL), followed by T. capitata, whereas M. piperita displayed weaker activity. PCA confirmed that phenolic monoterpenes drive both antimicrobial and antioxidant potency, while oxygenated terpenes and sesquiterpenes contribute more selectively. ADMET predictions indicated generally favorable absorption and low toxicity, although o-cymene and carvacrol presented potential safety concerns. Molecular docking revealed α-terpinyl acetate as the most versatile ligand, with strong binding to bacterial, fungal, and oxidative enzymes, whereas other compounds exhibited more selective affinities. Collectively, these findings highlight the potential of Moroccan EOs, particularly T. capitata and L. nobilis, as promising natural alternatives to synthetic antimicrobial and antioxidant agents.