In Vitro Anti-Cancer Activity of Native Curcumin and “Protein-Curcumin” Systems: A Perspective on Drug-Delivery Application

Curcumin is a natural polyphenolic compound with anti-cancer, anti-inflammatory, and anti-oxidation properties. Low water solubility and rapid hydrolytic degradation are two challenges that limit the use of curcumin as a therapeutic agent. In the current study, the role of the native/modified forms of bovine serum albumin (BSA) and casein, as foodgrade biopolymers and safe drug delivery systems, on the physical and biological activity of curcumin have been surveyed. Analyses of quenching of proteins fluorescence by curcumin indicated that chemical modification decreased the binding affinity of curcumin toward albumin whereas, it significantly increased for casein and the average number of binding sites also doubled in the modified casein. Measurement of cell viability using LDH assay showed that cytotoxicity of protein-bound curcumin is higher than free curcumin. Moreover, in the presence of native proteins, curcumin revealed elevated in vitro anti-cancer activity (against MCF7 and SKNMC) compared to modified forms. It appears that BSA and casein as protein vehicles are useful tools to increase both food quality and the bioavailability of curcumin as a health promoting agent. However, results imply that the chemical modification of proteins cannot improve the anti-cancer activity of curcumin despite increasing of their binding affinity.