Study of a water-soluble supramolecular complex of curcumin and β-cyclodextrin polymer with electrochemical property and potential anti-cancer activity

Abstract

As a member of the curcuminoid compound family, curcumin (Cur) has many interesting therapeutic properties. However, its low aqueous solubility and stability have resulted in poor bioavailability and restricted clinical efficacy. Based on size matching, β-cyclodextrin polymer (β-CDP), with its hydrophilic polymer chains and hydrophobic cavities, can form an inclusion complex with Cur. To improve the water solubility and stability of Cur, a simple and eco-friendly grinding method was designed to form β-CDP inclusion complexes. According to the Boltzmann–Hamel's method and Job's method, the molar ratio of the β-CD unit in β-CDP to Cur was determined to be 1:1. The diffusion coefficient and diffusion activation energy of Cur-β-CDP were calculated in an electrochemical study. This supramolecular complex worked well in vitro to inhibit the proliferation of hepatoma carcinoma cells HepG2. Remarkably, this method visibly reduced the undesirable side effects on normal cells, without weakening the anti-cancer activity of the drugs. We expect that the obtained host–guest complex will provide a new approach for delivering natural drug molecules, having low water solubility.