Phytochemical Characterisation, antioxidant, anti-inflammatory, antibacterial, antibiofilm, anticancer properties and therapeutic potentials of Eucalyptus globulus essential oil

The Eucalyptus globulus essential oil (EGEO) is widely recognized for its pharmacological relevance; however, comprehensive evaluation of its phytochemical composition and bioactivities remains limited. In this study, EGEO was extracted from fresh leaves via hydro-distillation and characterized using GC-MS, LCMS, FTIR, and UV-Visible spectroscopy. Qualitative screening confirmed the presence of key secondary metabolites, including triterpenoids, flavonoids, phenols, steroids. Quantitative analysis revealed high levels of total phenolics (65.12 ± 0.01 mg GAE/g) and flavonoids (57.75 ± 0.01 mg QE/g). The oil exhibited concentration-dependent antioxidant activity in the DPPH assay with an IC₅₀ value of 604.01 µl/mL, indicating potent radical-scavenging ability. Anti-inflammatory assessment through protein denaturation and human red blood cell (HRBC) membrane stabilization assays demonstrated moderate inhibitory and cytoprotective effects comparable to standard drugs. EGEO also showed strong antibacterial efficacy against Tannerella forsythia, Prevotella intermedia and Aggregatibacter with inhibition zones of 19-25 mm while showed notable antibiofilm activity against T. forsythia. Cytotoxic evaluation indicated selective action, showing minimal toxicity toward normal L929 fibroblasts and moderate inhibition of B16F10 melanoma cells. Overall, these findings suggest that Eucalyptus globulus essential oil is a rich source of bioactive phytoconstituents with potential therapeutic applications as a natural antioxidant, anti-inflammatory, antibacterial, antibiofilm, and anticancer agent.