Curcumin encapsulation in self-assembled nanoparticles based on amphiphilic palmitic acid-grafted-quaternized chitosan with enhanced cytotoxic, antimicrobial and antioxidant properties

The practical application of curcumin (CUR) is greatly limited due to its instability, high hydrophobicity, low bioavailability, and inability to cross the mucosal barrier of gastrointestinal tract. To overcome these disadvantages, several delivery systems have been explored to formulate CUR for oral administration. Nanoparticles (NPs) can significantly enhance oral absorption, bioavailability and therapeutic efficacy of drug, however, NPs are limited by the gastrointestinal degradation, mucosal and epithelial barriers. A novel amphiphilic quaternary ammonium chitosan (N-2-HACC) based NP delivery carrier was prepared using palmitic acid (PA) to encapsulate CUR. Palmitoyl chitosan (PA-N-2-HACC) was characterized including FT-IR, H-1 NMR, TGA, and CAC. The particle size of PA-N-2-HACC NPs and PA-N-2-HACC NPs loaded with CUR (CUR@PA-N-2-HACC NPs) was 231.6 +/- 9.24 nm and 264.5 +/- 4.31 nm. The encapsulation efficiency and loading capacity of CUR@PA-N-2-HACC NPs was 75.43 +/- 1.25 % and 6.81 +/- 0.16 %. CUR@PA-N-2-HACC NPs exhibited sustained and controlled release. Compared with the CUR, minimum inhibitory concentration of the CUR@PA-N-2-HACC NPs against Escherichia coli, Staphylococcus aureus and Candida albicans was reduced by 4.2 times, 1.6 times and 4.6 times, respectively. Moreover, the antioxidant activity of CUR@PA-N-2-HACC NPs was dose-dependent and higher than that of free CUR. The PA-N-2-HACC NPs show little toxicity and are a promising delivery system for encapsulating hydrophobic drugs.