Abstract

Oxidative stress has long been associated with the pathogenesis of inflammatory bowel disease (IBD), and it has been suggested that the combined administration of antioxidants and anti-inflammatory agents may be helpful for its treatment. Biopeptides from plant proteins, such as soybean glycinin tripeptide VPY, effectively inhibit pro-inflammatory mediators in intestinal epithelial and immune cells, which are both involved in the patho-genesis of IBD. This study aimed to produce antioxidant biopeptides from proteins of Lupinus mutabilis seeds and then encapsulate them in chitosan nanoparticles (NPs) for colonic delivery. An antioxidant peptide fraction of less than three kDa (UF3) was obtained and added at different concentrations (0.1-0.4 mg/ml) in chitosan so-lutions. The NPs were prepared by gelation with tripolyphosphate (CTPP-UF3) or spray freeze-drying of the chitosan solution (SFDC-UF3). Sizes of 332 +/- 13 and 465 +/- 58 nm and maximum encapsulation efficiencies of 63.80 and 71.75%, respectively, were obtained. UF3 maintained its antioxidant capacity (>80%) and showed different release profiles in 1X PBS buffer at pH 7.4, depending on the encapsulation method. FT-IR showed hydrogen bonding and electrostatic interactions between the peptide and chitosan. Both nanosystems maintained cell viability greater than 70% in colonic cell lines HT-29. These results show that both methods are appropriate for the nanoencapsulation of UF3 and can be used to design nanoparticles for colonic delivery.