Abstract:
To investigate the interaction mechanism between bovine serum albumin (BSA) and naringenin (Nar), as well as the impact on the stability of Nar, multi-spectroscopic techniques were initially utilized to study the quenching mechanism, binding constant, and binding site of the BSA-Nar complex. Subsequently, molecular dynamics simulations were conducted to explore the binding free energy, key residues, binding modes, and interactions. Finally, Nar/BSA nanoparticles (Nar/BSA NPs) were prepared, and the antioxidant activity and in vitro release properties were examined. The findings indicated that Nar can quench the intrinsic fluorescence of BSA through a static quenching mechanism. The BSA-Nar complex is primarily formed via hydrogen bonding and hydrophobic interactions, with a binding constant of 1.7×10
4 L/mol and a binding free energy of -14.78 kcal/mol. The secondary structure of BSA was altered, with the
α-helix content decreasing from 79.39% to 77.67%. There was approximately one binding site between BSA and Nar, and Nar binds to site I of BSA. Key residues Arg208, Ala212, Leu326, and Gly327 significantly contributed to the binding. Furthermore, after six days of storage, when the concentration was 40 µg/mL, the DPPH free radical scavenging rates of Nar/BSA NPs and Nar were 11.42% and 9.30%, respectively. Following 61 hours of simulated gastric fluid digestion, the release rates of Nar/BSA NPs and Nar were 62% and 79%, respectively. The corresponding release rates in simulated intestinal fluids were 86% and 89%, respectively. These results demonstrate that BSA can stably bind with Nar, and the antioxidant activity of Nar is significantly enhanced upon encapsulation with BSA. Additionally, the release rates of Nar in simulated gastric and intestinal fluids are slowed when encapsulated within BSA.