Investigation of the interaction between naringin and human serum albumin

The interaction between naringin and human serum albumin (HSA) has been thoroughly studied by fluorescence quenching technique in combination with UV absorption spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, circular dichroism (CD) spectroscopy and molecular modeling method. Under the simulative physiological conditions, fluorescence data revealed the presence of the binding site on HSA and its binding constants (K) are 1.62 × 104, 1.68 × 104, 1.72 × 104, and 1.79 × 104 M−1 at 289, 296, 303, and 310 K, respectively. The alterations of protein secondary structure in the presence of naringin aqueous solution were qualitative and quantitative calculated by the evidence from CD and FT-IR spectroscopes. In addition, according to the Van’t Hoff equation, the thermodynamic functions standard enthalpy (ΔH0) and standard entropy (ΔS0) for the reaction were calculated to be 3.45 kJ mol−1 and 92.52 J mol−1 K−1. These results indicated that naringin binds to HSA mainly by a hydrophobic interaction. Furthermore, the displacement experiments confirmed that naringin could bind to the site I of HSA, which was also in agreement with the result of the molecular modeling study.