Nanoemulsified Ocotea indecora Essential Oil: Improved Antifungal and Antimicrobial Performance

Antimicrobial resistance, along with fungal contamination, continues to pose significant risks to public health and agricultural systems, underscoring the urgent need for novel alternatives. Bioactive compounds derived from plants represent a promising source, and their effectiveness may be further improved through nanoformulation strategies. This work evaluated the antimicrobial activity of Ocotea indecora essential oil and its corresponding nanoemulsion. GC-MS analysis of the essential oil identified sesquirosefuran (91.61%) as the dominant compound. An optimized nanoemulsion was developed using a factorial design, producing stable spherical nanodroplets with an average size of 79 nm and a PdI of 0.029, demonstrating long-term stability. The essential oil inhibited both Gram-positive and Gram-negative bacteria at concentrations of 1-2 mg/mL, whereas the nanoemulsion significantly enhanced bactericidal efficacy against Staphylococcus aureus. Conversely, antifungal testing showed stronger activity, with the nanoemulsion reducing the minimum inhibitory concentration to 625 µg/mL against Thielaviopsis ethacetica, thereby enhancing the antifungal performance of the essential oil (2.5 mg/mL). Microscopic analysis further revealed structural damage, including reduced hyphal thickness and disrupted sporulation, indicating decreased fungal virulence. Overall, O. indecora essential oil demonstrates notable antimicrobial properties, and nanoemulsification was particularly effective in enhancing antifungal activity, with only modest improvements in antibacterial activity. These findings highlight O. indecora derivatives as promising natural resources for the development of new antimicrobial therapies.