β-Cyclodextrin Encapsulates Biochanin A and Influences its Binding to Bovine Serum Albumin: Alteration of the Binding Strength

We report the host–guest association of Biochanin A with β-cyclodextrin and the modulation of its binding by cyclodextrin to bovine serum albumin. The binding constant of the complex is large. The strength of the binding of Biochanin A to bovine serum albumin decreases when β-cyclodextrin complexes with it. The binding constants of the Biochanin–serum albumin binding in the absence and the presence of cyclodextrin are (2.23 ± 0.08) × 106 and (1.37 ± 0.05) × 106 mol−1·dm3, respectively. The FRET studies reveal the decrease in the distance between the donor and the acceptor in the presence of cyclodextrin.