Phytochemical Profiling, Antioxidant, and Broad-Spectrum Antimicrobial Activities of <i>Origanum vulgare</i> Essential Oil with Molecular Docking and ADME Insights

This study evaluated the chemical composition, antimicrobial, antioxidant, and pharmacological properties of <i>Origanum vulgare</i> essential oil (OVEO). Gas chromatography-mass spectrometry (GC-MS) identified carvacrol (50%), γ-terpinene (13.5%), thymol (9.5%), and <i>p</i>-cymene (7.8%) as the principal constituents. Antioxidant testing using DPPH and <i>o</i>-phenanthroline assays revealed moderate activity compared with synthetic standards. Antimicrobial assays demonstrated strong effects, with inhibition zones reaching 58 mm against <i>Staphylococcus aureus</i> and complete inhibition of <i>Candida albicans</i> and <i>Candida parapsilosis</i>. Minimum inhibitory concentrations (MICs) confirmed the potency of OVEO, with <i>Klebsiella pneumoniae</i> inhibited at concentrations as low as 0.037 mg/mL. At the same time, <i>S. aureus</i> and <i>Enterococcus faecalis</i> exhibited susceptibility to 0.125-0.50 mg/mL, while <i>Enterobacter cloacae</i> showed reduced susceptibility (MICs up to 4.78 mg/mL). Fungal pathogens were highly sensitive, with MICs ranging from 0.06 to 0.6 mg/mL. Molecular docking revealed β-caryophyllene as a key compound, exhibiting strong binding affinities (-6.0 to -8.2 kcal/mol) across bacterial, fungal, and viral protein targets. Importantly, ADME predictions showed that β-caryophyllene complies with Lipinski's Rule of Five and possesses favorable oral bioavailability, supporting its potential as a drug-like compound. In summary, these findings demonstrate that <i>O. vulgare</i> essential oil, rich in phenolic monoterpenes and sesquiterpenes, possesses broad-spectrum antimicrobial activity and moderate antioxidant capacity, with β-caryophyllene emerging as a promising pharmacological candidate. These results highlight the potential of OVEO as a natural antimicrobial agent and adjuvant to conventional therapies, while emphasizing the need for further in vivo validation.