Safety and potential functionality of nanoparticles loaded with a trypsin inhibitor isolated from tamarind seeds

The trypsin inhibitor isolated from tamarind seeds (TTI) presents satietogenic and anti-inflammatory effects. In the present study, TTI encapsulation by nanoprecipitation in purified chitosan and whey protein isolate (ECW) was performed to maintain TTI's integrity and protection through the gastrointestinal tract. The interaction between TTI and the encapsulating agents was determined by filtration monitoring the antitrypsin activity. Cytotoxicity was evaluated at different concentrations (0.5, 2.5 and 5.0 mg/mL) in Caco-2 and CCD-18Co cells. Subacute blood toxicity was evaluated in Wistar rats (12.5 mg/kg) for ten days. The particles presented a smooth surface, with 118.00 (17.27) nm of diameter, 0.37 (0.02) of polydispersity index, -38.26 (0.15) mV (neutral pH) of surface charge, and 95.31 (0.31)% of incorporation efficiency. At neutral pH, there was a strong interaction of the encapsulating agents and TTI, and a gradual release of TTI at pH 3.0. Cell viability (> 70%) evaluation, in vivo biochemical and hepatic parameters of Wistar rats showed the absence of toxic effects of the nanoparticles with TTI. The study showed that TTI nanoparticles are potentially safe and represent a promising formulation for the clinical application of TTI and may become an option as a novel ingredient in food.