Enhanced antifungal and cytotoxic potential of essential oils encapsulated in polydopamine nanocapsules against Candida albicans and Pichia kudriavzevii

Oral fungal infections, particularly those caused by Candida albicans and Pichia kudriavzevii, pose significant health challenges, especially in immunocompromised individuals. This study systematically investigates the antifungal efficacy, antioxidant, and antiproliferative of essential oils (EOs) from Mentha longifolia and Cupressus macrocarpa, encapsulated in polydopamine (PDA) nanocapsules to enhance their stability and bioactivity. Compositional analysis using gas chromatography-mass spectrometry (GC-MS) identified key bioactive compounds contributing to their antifungal and antioxidant properties. The nanocapsules were further characterized using Fourier-transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), dynamic light scattering (DLS), and zeta potential analysis, confirming their successful encapsulation, nanoscale morphology, and surface charge stability. The encapsulated EOs demonstrated significantly enhanced antifungal activity, with lower minimum inhibitory concentrations (MICs) than their non-encapsulated counterparts. Additionally, they exhibited strong antioxidant potential in the DPPH assay and notable cytotoxic effects against MCF-7 and HepG-2 cancer cell lines. TEM provided direct evidence of fungal cell disruption, including chromatin condensation, membrane damage, and cytoplasmic leakage, indicating apoptosis and necrosis. The synergistic interaction between EOs and PDA, confirmed by fractional inhibitory concentration index (FICI) analysis, highlights their potential as effective antifungal agents. These findings strongly support EO-PDA nanocapsules as a promising alternative for treating oral fungal infections while also exhibiting potential anticancer properties.