Bixin loaded on polymeric nanoparticles: synthesis, characterization, and antioxidant applications in a biological system

Acute lung inflammation (ALI) is a disease caused by many factors including cigarette smoke (CS) exposure. Natural products have demonstrated interesting antioxidant and anti-inflammatory activities able to prevent the damage caused in the lungs by CS. Annatto seed alkaline extract is rich in a pigment called bixin, which has a potent antioxidant effect but is too poorly hydrophilic, making it difficult to use in oral treatments and putting it as an attractive molecule for been loaded on polymeric nanoparticles. Therefore, in this study, we aimed to develop and characterize nanoparticles of bixin (npBX) and to conduct initial tests in vivo with oral treatment of ALI induced by CS in C57BL/6 mice with npBX. Bixin was purified from annatto seeds with a high degree of purity and rigorously characterized. Nanoparticles were developed using the interfacial deposition method and showed a mean hydrodynamic diameter of 23.7 ± 0.2 nm, polydispersity index of 0.226 ± 0.006, zeta potential of − 21.69 ± 9.90 mV, and drug loading of approximately 24.23 ± 0.41 mg/g. Treatment with npBX prevented increases in superoxide anion and total bronchoalveolar lavage leukocyte levels in mice exposed to CS. These data provide support for npBX as a promising therapeutic tool for lung diseases.