pH-driven preparation of pea protein isolate-curcumin nanoparticles effectively enhances antitumor activity

Soluble pea protein isolate-curcumin nanoparticles were successfully prepared at a novel pH combination, with encapsulation efficiency and drug loading amount of 95.69 +/- 1.63 % and 32.73 +/- 0.56 mu g/mg, respectively, resulting in >4000-fold increase in the water solubility of curcumin. The encapsulation propensity and interaction mechanism of pea protein isolates with curcumin and colchicine were comparatively evaluated by structural characterization, molecular dynamics simulations and molecular docking. The results showed that the nanoparticles formed by curcumin and colchicine with pea protein isolates were mainly driven by hydrogen bonding and hydrophobic interactions, and the binding process did not alter the secondary structure of pea protein. In contrast, pea protein isolate-curcumin nanoparticles exhibited smaller particle size, lower RMSD value, lower binding Gibbs free energy and greater structural stability. Therefore, pea protein isolate is a suitable encapsulation material for hydrophobic compounds. Furthermore, the pea protein isolate-curcumin nanoparticles showed remarkably enhanced antitumor activity, as evidenced by a significant reduction in IC50, and the anti-tumor mechanism of it involved the ROS-induced mitochondria-mediated caspase cascade apoptosis pathway. These findings provide insights into the development of pea protein-based delivery systems and the possibility of a broader application of curcumin in antitumor activity.