Development of Xanthyletin-Loaded Nanoparticles for the Control of Leucoagaricus gongylophorus

This study describes the development, characterization and in vitro evaluation of poly(ε-caprolactone) (PCL) nanoparticles loaded with xanthyletin for the control of <i>Atta sexdens rubropilosa</i> through the inhibition of its symbiotic fungus <i>Leucoagaricus gongylophorus</i>. Nanoparticles were prepared via interfacial polymer deposition, with formulation NC5 selected based on optimal physicochemical properties. NC5 exhibited an encapsulation efficiency of 98.0%, average particle size of 304 nm and zeta potential of -29.3 mV. Scanning electron microscopy confirmed spherical morphology and the absence of crystalline residues. The formulation remained physically stable for four months at 4 °C. In vitro release showed biphasic behavior, with an initial burst followed by sustained release. Under UV exposure, NC5 enhanced xanthyletin photostability by 15.4-fold compared to the free compound. Fungicidal assays revealed 76% inhibition of fungal growth with NC5, compared to 85% with free xanthyletin. These results support the potential application of xanthyletin-loaded PCL nanoparticles as a stable and controlled delivery system for the biological control of leaf-cutting ants by targeting their fungal mutualist. Further in vivo studies are recommended to assess efficacy under field conditions.