Spectroscopic study on the interaction of resveratrol and pterostilbene with human serum albumin

The interaction of human serum albumin (HSA) with two stilbene compounds, resveratrol and pterostilbene was investigated using fluorescence, UV-visible absorption, Fourier transform infrared spectroscopic methods and molecular modeling technique. The intrinsic fluorescence of HSA was quenched significantly by resveratrol and pterostilbene. Analysis of fluorescence quenching data of HSA by the two compounds using Stern-Volmer and modified Stern-Volmer methods showed the formation of ground state complexes of HSA with resveratrol and pterostilbene. The binding analysis showed that the binding constant for resveratrol as 4.47×10(6) and 0.299×10(2)M(-1)s(-1) for pterostilbene revealing the high binding affinity of resveratrol to HSA. The conformational changes of HSA were investigated using synchronous fluorescence and Fourier transform infrared spectroscopy. The efficiency of energy transfer and the distance between HSA and resveratrol/pterostilbene were calculated. The binding of resveratrol/pterostilbene was modeled by molecular docking, which is in accordance with the experimental data.