Curcumin Nanoencapsulated in Chitosan-Coated Liposomes: Therapeutic Potential against Pathogenic Escherichia coli and Leishmania spp.

Infectious diseases caused by bacteria and protozoa continue to pose a critical public health challenge, exacerbated by the increasing resistance to conventional treatments. Curcumin, a broad-spectrum polyphenol with antimicrobial and antiparasitic properties, nevertheless presents clinical limitations associated with low solubility, chemical instability, and reduced bioavailability. In this study, curcumin nanoencapsulated into chitosan-coated liposomes (Lipo-CUR-Chi) was developed and characterized to evaluate its physicochemical performance, stability, antibacterial and antibiofilm activity against Escherichia coli strains, and antiparasitic efficacy against Leishmania infantum and L. amazonensis. The formulation showed high encapsulation efficiency (97.2%), stability for up to 120 days under refrigeration, and a marked increase in antimicrobial activity compared to free curcumin. A significant reduction in minimum inhibitory concentrations against E. coli was observed, along with a dose-dependent effect on biofilm formation inhibition. In RAW 264.7 macrophages, Lipo-CUR-Chi demonstrated lower cytotoxicity, indicating higher safety compared to free curcumin. In assays against Leishmania spp., CUR encapsulation resulted in increased potency and selectivity, particularly against L. amazonensis, approaching the therapeutic profile of amphotericin B but with lower toxicity. These results demonstrate that chitosan-coated liposomes are a promising platform to enhance the biological activity of curcumin, representing an innovative strategy for the treatment of bacterial and parasitic infections.