Binding Modes of Cabergoline to Bovine Serum Albumin in Free- and β-Cyclodextrin-Encapsulated Forms: Differences in Quenching Behavior and Förster Resonance Energy Transfer

We report, in this paper, the interaction of cabergoline in the free form and β-cyclodextrin-bound form with bovine serum albumin. The stoichiometry and the binding constant of the Cabergoline–β-cyclodextrin inclusion complex are reported based on UV–Vis absorption and fluorescence spectroscopic studies and the structure of the 1:1 inclusion complex is proposed using two-dimensional rotating-frame Overhauser effect spectroscopy. Molecular docking is used to propose the mode of interaction of cabergoline with bovine serum albumin. The apparent binding constants for the interaction of cabergoline with bovine serum albumin in water and in aqueous β-cyclodextrin solution are compared. The average distance between donor and acceptor is altered in the presence of β-cyclodextrin, as indicated by Forster resonance energy transfer. The influence of β-CD on the binding of the small molecule with bovine serum albumin is discussed.