Designing Biocompatible Protein Nanoparticles for Improving the Cellular Uptake and Antioxidation Activity of Tetrahydrocurcumin

Abstract Tetrahydrocurcumin (THC) is a natural molecule with anticancerous, antioxidant and other beneficial activities. However, its low aqueous solubility leads to poor bioavailability. Sodium caseinate (NaCas) is an ideal natural protein carrier with amphiphilic and non-toxic properties, which provides a new possibility for improving the aqueous solubility of THC. In this study, THC loaded protein nanoparticles (THC@NaCas) were successfully prepared by a nanoprecipitation method. The protein-based carrier awarded an encapsulation efficiency of about 98 % for THC. The structure and physicochemical characteristics of THC@NaCas nanoparticles were characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction, and Scanning Electron Microscopy (SEM). The solubility test comfirmed that protein nanoparticles awarded greater solubility of THC. Furthermore, THC@NaCas had a greater antioxidant activity compared to free THC, resulting in a free radical scavenging ability of THC@NaCas 2.6 times greater than that of free THC. The in vitro cytotoxicity test showed that the THC@NaCas nanoparticles had a stronger inhibitory effect on cancer cells compared with free THC, and good biocompatibility for non-cancerous cells. In a short, Our results demonstrate that protein-based nanoparticles have the potential to improve the bioactivity of hydrophobic drugs in clinical application.