Spectroscopic studies on the interaction of bovine serum albumin with Ginkgol C15:1 from Ginkgo biloba L.

The interaction between Ginkgol C15:1 (Ginkgol), a natural bioactive compound from Ginkgo biloba, and bovine serum albumin (BSA) was studied by fluorescence, UV-vis absorption, Fourier transform infrared (FT-IR) and circular dichroism (CD) spectroscopy under simulative physiological conditions. The results showed that the fluorescence quenching of BSA by Ginkgol was a static quenching procedure through forming a 1:1 ground-state Ginkgol-BSA complex with a binding constant of about 2.6×103 L mol−1. The values of the thermodynamic parameters indicated that electrostatic and hydrophobic forces played important roles in the interaction of BSA with Ginkgol. The binding distance between BSA and Ginkgol was 3.37 nm, based on Föster's non-radiative energy transfer theory, and subdomain IIA (Sudlow site I) was the primary binding site which was consistent with that results of molecular docking modeling. The results of UV-vis, CD, three-dimensional fluorescence and FT-IR spectra indicated that binding of Ginkgol to BSA induced conformational changes of BSA.