Schinus terebinthifolius essential oil encapsulated in chitosan-coated PCL nanocapsules: A strategy against leishmaniasis and multidrug-resistant bacterial infections

In recent decades, diseases caused by parasites of the genus Leishmania and multidrug-resistant (MDR) bacteria have posed a major challenge to public health, as these diseases present therapeutic limitations, including high toxicity of conventional drugs, high costs, resistance, and risk of serious complications for patients. Red aroeira essential oil (OE-Aro) has several biological properties, but it has limitations, such as high volatility and low stability. Therefore, chitosan-coated polycaprolactone (PCL) nanocapsules may be a strategy for encapsulating OE-Aro in order to overcome its limitations and enhance its biological activities. Thus, this study aimed to evaluate the anti- Leishmania and antibacterial activity of PCL nanocapsules with and without chitosan coating containing OE-Aro (Nc-Aro-CH and Nc-Aro-PCL, respectively). The Nc-Aro-PCL particles had a size of 264.2 nm, PDI of 0.070, and zeta potential of -38.4 mV. Nc-Aro-PCL and Nc-Aro-CH demonstrated strong potential against amastigote forms of L. infantum with IC50 values of 0.0089 mg/mL and 0.0127 mg/mL, while for amastigote forms of L. amazonensis , Nc-Aro-PCL and Nc-Aro-CH had IC50 values of 0.0101 mg/mL and 0.0219 mg/mL, respectively. The nanocapsules showed antibacterial and antibiofilm activity against clinically important strains with and without resistance profiles of the genus Staphylococcus . In addition, low cytotoxicity of the nanoformulations was observed in RAW macrophages and NCTC 929 murine fibroblasts. These results suggest that the nanocapsules have great leishmanicidal and antibacterial potential and may be an alternative for the treatment of leishmaniasis and secondary infections caused by bacteria.