Nanoencapsulation of Antifungal Piper schlechtendalii Extract in Poly(lactide-co-glycolic) Acid to Enhance Photostability

Synthetic fungicides are used to control fungal diseases in plants, such as those caused by members of the Fusarium genus. Nonetheless, the over-application of synthetic formulations can generate other problems, like phytotoxicity, or the pollution of water and soil. In this context, botanical extracts with antifungal properties can represent an environmentally friendly alternative to control fungal infections. The application of natural products in the form of crude extracts still requires the incorporation of toxic organic solvents to be used as vehicle. Nanotechnology allows the dispersion of hydroalcoholic extracts in water simply by the nanoencapsulation of the active molecules in a biodegradable polymer, with the advantage that no organic solvents are required while, at the same time, this polymer may protect the extract against photodegradation. The present study aims to encapsulate an antifungal Piper schlechtendalii crude extract in poly(lactide-co-glycolide) acid nanospheres, conferring good dispersion in water while protecting the active ingredients against degradation by solar irradiation. The particle size, zeta potential, and encapsulation efficiency obtained were 170 nm, -37 mV, and 33.7 %, respectively. The system obtained showed good dispersion in water, in the form of a colloidal suspension of polymeric nanospheres. After 24 h of exposure to UV-A radiation, crude extract only retained 58.35 % of its original Fusarium solani growth inhibition capacity, while the nanoencapsulated extract retained 70 %. The study concluded that the biodegradable polymer does confer photoprotection to the active ingredients in the antifungal Piper extract while simultaneously removing the necessity of organic solvents as vehicles, potentially reducing the environmental impact. Resumen. Los fungicidas sintéticos son usados para controlar enfermedades fúngicas en plantas, como aquellas causadas por el género Fusarium. Sin embargo, la aplicación desmedida de formulaciones sintéticas puede generar otros problemas, como fitotoxicidad, o contaminación de agua y suelos. En este contexto, extractos botánicos con propiedades antifúngicas representan una alternativa ecológicamente amigable para controlar infecciones fúngicas. La aplicación de productos naturales en forma de extractos crudos aún requiere la incorporación de disolventes orgánicos tóxicos para ser utilizados como vehículos. La nanotecnología permite la dispersión de extractos hidroalcóholicos en agua si