In Vitro Cytotoxic Activity and Binding Properties of Curcumin in the Presence of β-Casein Micelle Nanoparticles

Curcumin (CUR) is the active curcuminoid with many physiological, biochemical, and pharmacological properties. Solubility and stability of CUR is the limiting factors for realizing its therapeutic potential. Bovine βcasein is an abundant milk protein that is highly hiphilic and selfassembles into stable micellar nanoparticles in aqueous solution. βCasein nanoparticle can solubilize CUR molecules. In the present study, we introduced a drugdelivery system comprising hydrophobic anticancer drug, CUR, entrapped within βcaseinbased nanoparticles. The interaction of CUR with βcasein was investigated using steadystate fluorescence spectroscopy and molecular docking calculation. Results showed that at pH 7, CUR molecules bind to βcasein micelle and formed complexes through hydrophobic interactions. Förster energy transfer measurements and molecular docking studies suggested that CUR molecules bind to the hydrophobic core of βcasein. The binding parameters including number of substantive binding sites and the binding constant were evaluated by fluorescence quenching method. Additionally, the cytotoxicity of free CUR and CURβcasein complex to human breast cancer cell line MCF7 was evaluated in vitro. The study revealed that the CURβcasein complex exhibited better cytotoxic effects on MCF7 cells compared to equal dose of free CUR.