Spectroscopic studies on the interaction between an anticancer drug ampelopsin and bovine serum albumin.

The interaction between bovine serum albumin (BSA) and the anticancer drug molecule ampelopsin (AMP) was investigated using fluorescence spectroscopy, circular dichroism (CD) spectra, and time-resolved spectra under simulated physiological conditions. Fluorescence data showed that the intrinsic fluorescence of BSA was strongly quenched by AMP in terms of a dynamic quenching process. Binding constants and binding sites were calculated. The thermodynamic parameters indicated that the hydrogen bonding and weak van der Waals force played a major role in the interaction. The site marker competitive experiments suggested that the binding site of AMP and BSA was probably located on site III. Based on the Förster's theory, the average binding distance between AMP and BSA was obtained (r=5.47nm). The binding of AMP and BSA leaded to conformational changes of BSA according to synchronous fluorescence spectra, CD data and mean fluorescence lifetime values.