Analysis of chemical composition, antibacterial activity, antioxidant properties, and cytotoxicity of essential oils from four plant fruits

Amid growing concerns about milk safety and antimicrobial resistance, the development of antibiotic alternatives for bovine mastitis has become increasingly important. Essential oils (EOs) derived from the fruits of four medicinal plants were extracted using steam distillation. Gas chromatography–mass spectrometry analysis revealed distinct chemical profiles: Wurfbainia vera EO (WvEO, 84.00 % eucalyptol), Cnidium monnieri EO (37.47 % d-limonene/34.49 % α-pinene), Alpinia oxyphylla EO (51.64 % o-cymene), and Lanxangia tsao-ko EO (LtEO, 50.02 % eucalyptol). Antimicrobial assays demonstrated that both WvEO and LtEO inhibited key pathogens associated with bovine mastitis, including Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Streptococcus agalactiae, and Streptococcus dysgalactiae. Notably, LtEO exhibited lower minimum inhibitory concentrations (1.875–7.5 mg/mL). When combined, WvEO and LtEO showed synergistic antibacterial activity. Antioxidant activity assays further indicated that LtEO possessed stronger antioxidant capacity than WvEO, while the two oils together produced synergistic antioxidant effects (combination index <1). Cytotoxicity testing in bovine mammary epithelial cells revealed that LtEO had a superior safety profile (EC₅₀: 0.091 vs 0.531 mg/mL). Molecular docking analysis confirmed strong binding affinities between EO components and critical targets, including dihydrofolate reductase, glutathione reductase, and lipoxygenase. Taken together, these findings highlight WvEO and LtEO as promising phytotherapeutic candidates for the prevention and management of bovine mastitis.