Vol. 11, Issue 4, Part C (2025)

Introduction: The oral cavity harbors a complex microbiota, some of which are directly implicated in periodontal disease. Conventional chemotherapeutic agents and mechanical approaches are widely used for periodontal therapy; however, issues such as microbial resistance and systemic toxicity limit their long-term application. In this context, Eucalyptus globulus, a natural phytochemical agent, has demonstrated promising antimicrobial properties against oral pathogens, including Porphyromonas gingivalis. Objective: To comparatively evaluate the antibacterial efficacy of aqueous and ethanolic extracts of Eucalyptus globulus leaves against P. gingivalis. Methodology: Leaves of E. globulus were washed, dried, and powdered. Ethanolic and aqueous extracts were prepared using a Soxhlet apparatus. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by serial broth dilution. Extract concentrations ranged from 100 mg/mL to 0.2 mg/mL, with tetracycline serving as the control. Following 48 hours of incubation, turbidity was used as an indicator of bacterial growth. Comparative analysis of MIC and MBC values was performed for both extracts and tetracycline against P. gingivalis. Results: Aqueous extract of E. globulus inhibited the growth of P. gingivalis at a MIC of 0.8 mg/mL, whereas the ethanolic extract demonstrated inhibition at 1.6 mg/mL. Tetracycline exhibited antibacterial activity at 0.2 mg/mL. Bactericidal activity was observed at 6.25 mg/mL for the aqueous extract and 12.5 mg/mL for the ethanolic extract. Statistical analysis showed significant differences (p < 0.05) in antimicrobial activity between extracts and the negative control. Conclusion: Both aqueous and ethanolic extracts of E. globulus displayed antibacterial activity against P. gingivalis. The aqueous extract demonstrated superior antimicrobial efficacy compared to the ethanolic extract, suggesting its potential as a natural adjunct in periodontal therapy.