Development of curcumin-loaded hyaluronic acid complexes for curcumin intestinal delivery: Preparation, characterization, antioxidant, and in vitro digestive properties

In this study, the hyaluronic acid complexes loaded with curcumin were prepared using a pH cycling method, with hyaluronic acid as the wall material. This approach aims to enhance the bioaccessibility of curcumin and provide a new loading strategy for applying fat-soluble polyphenols. The results indicated that a mass ratio of curcumin to hyaluronic acid of 1:30 produced the smallest particle size of the complex (388 nm). Additionally, the encapsulation and loading rates of curcumin were 96.34% and 3.11%, respectively. Fourier transform infrared (FT-IR) spectroscopy and simultaneous thermal analysis revealed that curcumin primarily binds to hyaluronic acid through hydrogen bonding and electrostatic interactions and is encapsulated in an amorphous state. Stability analysis demonstrated that the prepared complexes exhibited excellent stability under 0-500 mmol/L NaCl, pH 3-8, heating at 60-90 °C for 30 min, and storage at 4 °C and 25 °C for 28 d. Antioxidant experiments showed that hyaluronic acid embedding significantly enhanced curcumin's scavenging activity against DPPH radical and ABTS radical cation. Simulated in vitro digestion experiments indicated that the complex loading increased the bioaccessibility of curcumin from 32% to 51%. The findings of this study provide a theoretical foundation for the application of curcumin-loaded hyaluronic acid complexes in functional foods. • Curcumin-loaded hyaluronic acid complexes were prepared using a pH cycle method. • The main driving forces of complex formation were hydrogen bonding and electrostatic interactions. • The complexes presented excellent environmental stability. • The antioxidant capacity and bioaccessibility of curcumin were improved.