Polyelectrolyte Complex Nanoparticles from Chitosan and Acylated Rapeseed Cruciferin Protein for Curcumin Delivery

Curcumin is a polyphenol that exhibits several biological activities, but its low aqueous solubility results in low bioavailability. To improve curcumin bioavailability, this study has focused on developing a polyelectrolyte complexation method to form layer-by-layer assembled nanoparticles, for curcumin delivery, with positively charged chitosan (CS) and negatively charged acylated cruciferin (ACRU), a rapeseed globulin. Nanoparticles (NPs) were prepared from ACRU and CS (2:1) at pH 5.7. Three samples with weight of 5%, 10%, and 15% of curcumin, respectively, in ACRU/CS carrier were prepared. To verify the stability of the NPs, encapsulation efficiency and size of the 5% Cur-ACRU/CS NPs were determined at intervals of 5 days in a one month period. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, and differential scanning calorimetry confirmed the electrostatic interaction and hydrogen bond formation between the carrier and core. The result showed that hollow ACRU/CS nanocapsules (ACRU/CS NPs) and curcumin-loaded ACRU/CS nanoparticles (Cur-ACRU/CS NPs) were homogenized spherical with average sizes of 200-450 nm and zeta potential of +15 mV. Encapsulation and loading efficiencies were 72% and 5.4%, respectively. In vitro release study using simulated gastro (SGF) and intestinal fluids (SIF) showed controlled release of curcumin in 6 h of exposure. Additionally, the Cur-ACRU/CS NPs are nontoxic to cultured Caco-2 cells, and the permeability assay indicated that Cur-ACRU/CS NPs had improved permeability efficiency of free curcumin through the Caco-2 cell monolayer. The findings suggest that ACRU/CS NPs can be used for encapsulation and delivery of curcumin in functional foods.