Comment on “Insight into the interaction between tannin acid and bovine serum albumin from a spectroscopic and molecular docking perspective” by W. Xu, Y. Ning, S. Cao, G. Wu, H. Sun, L. Chai, S. Wu, J. Li and D. Luo, RSC Adv., 2023, 13, 10592

Abstract

In an article [W. Xu et al., RSC Adv., 2023, 13(16), 10592–10599], the authors characterized the interaction between tannic acid (TA) and bovine serum albumin (BSA) using a variety of biophysical techniques, including thermodynamic analysis. Upon examining their reported thermodynamic parameters, we identified an internal inconsistency: the enthalpy change (ΔH) was treated as temperature-independent, whereas the entropy change (ΔS) was reported as temperature-dependent, a combination that contradicts fundamental principles of equilibrium thermodynamics. In this Comment, we clarify the source of this inconsistency by reanalyzing the reported Gibbs free energy (ΔG) values and applying the appropriate thermodynamic relationships. Our analysis yields self-consistent values of ΔH and ΔS and underscores the limitations imposed by the small number of temperature data points. We further discuss the conditions under which heat-capacity effects (ΔC) can be meaningfully evaluated and recommend future experiments that incorporate additional temperature measurements. These refinements will enable a complete and internally consistent thermodynamic characterization of the TA–BSA interaction.