Enhanced solubility, bioaccessibility, and antioxidant activity of curcumin via lipase complexation: Structural insights and stability assessment.

Curcumin, a bioactive compound with diverse therapeutic properties, faces challenges in clinical applications owing to its limited solubility and poor bioaccessibility. This study proposes a novel strategy to enhance the aqueous solubility, bioaccessibility, and antioxidant potential of curcumin by complexation with lipase (PersiLip1). The optimal condition for complex formation was determined to be pH 7.0, resulting in a 90-fold increase in solubility, reaching 96.92 %. Antioxidant activity assays (ABTS and DPPH) revealed significant radical scavenging capacity. Structural characterization, including Scanning Electron Microscopy (SEM), Fourier-Transform Infrared Spectroscopy (FTIR), and X-Ray Diffraction (XRD), indicated a notable transformation of curcumin from its crystalline to amorphous state. Atomic Force Microscopy (AFM) confirmed the formation of larger, stable molecular assemblies, with a particle size increase from 4.68 nm (free curcumin) to 121 nm (Cur-Lip complex). Dynamic Light Scattering (DLS) analysis revealed a further increase in the particle size to 3214.10 nm, coupled with a reduced Polydispersity Index (PDI) of 0.23, suggesting enhanced homogeneity. Zeta potential analysis showed a reduction in surface charge. Storage stability assessments confirmed the sustained solubility of the Cur-Lip complex for over 30 days. These findings highlight lipase-assisted complexation as an effective strategy for enhancing the therapeutic potential of curcumin.