Diverse Effects of Different “Protein-Based” Vehicles on the Stability and Bioavailability of Curcumin: Spectroscopic Evaluation of the Antioxidant Activity and Cytotoxicity In Vitro

BACKGROUND: Curcumin is a natural polyphenolic compound with anti-cancer, anti-inflammatory, and anti-oxidation properties. Low water solubility and rapid hydrolyt-ic degradation are two challenges limiting use of curcumin. OBJECTIVE: In this study, the roles of the native/modified forms of Bovine Serum Albumin (BSA), β-lactoglobulin (β-lg) and casein, as food-grade biopolymers and also protein chemical modification, in stabilizing and on biological activity of curcumin were sur-veyed. METHODS: In this article, we used various spectroscopic as well as cell culture-based tech-niques along with calculation of thermodynamic parameters. RESULTS: Investigation of curcumin stability indicated that curcumin binding to the native BSA and modified β-lg were stronger than those of the modified BSA and native β-lg, respectively and hence, the native BSA and modified β-lg could suppress water-mediated and light-mediated curcumin degradation, significantly. Moreover, in the presence of the native proteins (BSA and casein), curcumin revealed elevated in vitro anti-cancer activity against MCF-7 (human breast carcinoma cell line) and SKNMC (human neuroblastoma cell line). As well, curcumin, in the presence of the unmodified “BSA and β-lg”, was more potent to decrease ROS generation by hydrogen peroxide (H2O2) whereas it led to an inverse outcome in the presence of native casein. Overall, in the presence of the pro-tein-bound curcumin, increased anti-cancer activity and decreased ROS generation by H2O2 in vitro were documented. CONCLUSION: It appears that “water exclusion” is major determinant factor for increased stability/efficacy of the bound curcumin so that some protein-curcumin systems may pro-vide novel tools to increase both food quality and the bioavailability of curcumin as health promoting agent.