Spectroscopic and isothermal titration calorimetry studies of binding interaction of ferulic acid with bovine serum albumin

The binding characteristics of ferulic acid (FA) with bovine serum albumin (BSA) were investigated using fluorescence, circular dichroism (CD) and isothermal titration calorimetry (ITC) techniques at pH 7.4. Fluorescence technique on basis of quenching method determined one class of binding site with binding constant (40.14 ± 0.02) × 104 (mol−1 dm3) at 298 K. Fluorescence anisotropy and lifetime study indicated significant microenvironment changes around FA upon interaction with BSA suggesting binding. The circular dichroism data indicated changes in the secondary structure of BSA upon binding with FA thus confirming the role of non-covalent forces and also suggested that thermal stability of BSA increases upon binding with FA. ITC data suggest that FA binds to BSA at two sites with high affinity and binding forces are mainly electrostatic and hydrogen bonding. Inconsistency between calorimetric enthalpy and Van’t Hoff enthalpy indicated appreciable conformational change in BSA upon binding of FA.