Antibacterial and Antifungal Properties of Ocotea indecora Essential Oil and Its Nanoemulsion

<b>Background:</b> Antimicrobial resistance and fungal contamination remain major threats to public health and agriculture, emphasizing the need for innovative alternatives. Plant-derived products are a promising alternative, and nanoformulations may further enhance their activity. <b>Objective:</b> This study investigated the antimicrobial potential of <i>Ocotea indecora</i> essential oil and its nanoemulsion. <b>Methods/Results:</b> The essential oil chemical characterization by GC-MS revealed sesquirosefuran (91.61%) as the main constituent. A factorial design guided the selection of an optimized nanoemulsion, which exhibited spherical nanometric droplets (79 nm and 0.029 PdI) with long-term stability. The essential oil inhibited the growth of Gram-positive and Gram-negative strains at 1 to 2 mg/mL, while the nanoemulsion enhanced bactericidal activity against <i>Staphylococcus aureus</i>. In contrast, antifungal assays revealed a more pronounced effect, with the nanoemulsion lowering the minimum inhibitory concentrations (625 µg/mL) against <i>Thielaviopsis ethacetica</i>, thereby enhancing the inhibitory activity of the essential oil (2.5 mg/mL). Morphological alterations, including thinner hyphae and impaired sporulation, were also detected, suggesting a reduction in fungal virulence. <b>Conclusions:</b> In summary, <i>O. indecora</i> essential oil shows promising antimicrobial potential, and nanoemulsification proved particularly effective in potentiating fungistatic activity while offering limited enhancement of bactericidal effects. The results support the potential of <i>O. indecora</i> derivatives as natural candidates for the development of novel antimicrobial strategies.