Comparative studies on biophysical interactions between gambogic acid and serum albumin via multispectroscopic approaches and molecular docking.

Abstract Gambogic acid (GA) is insecticidal and cytotoxic to various cancer cells. This study focused on mechanisms of interactions between GA and human serum albumin (HSA) and bovine serum albumin (BSA). Spectra of steady-state fluorescence, UV–Vis, and time-resolved fluorescence indicated that GA binding to HSA/BSA is a static process. The site maker experiments suggest that the binding for HSA-GA and BSA-GA systems both occurs at site II (subdomain IIIA). The complex of GA with HSA/BSA can distribute efficiently in vivo under the value of binding constants in the intermediate range. Thermodynamic parameters illustrate that the binding of GA to HSA/BSA is collaboratively driven by van der Waals force and a hydrogen bond in a spontaneous process. Molecular modeling studies revealed that the binding of GA to the site II via hydrogen bond and π-cation interactions. Such interactions between GA and HSA/BSA are informational for use of gambogic acid as a lead compound for insecticide development. Graphical abstract fx1 Highlights • GA-HSA/BSA interactions in vitro were studied by multispectroscopy techniques. • GA induces the conformational changes of HSA/BSA. • GA binds to the site II of HSA/BSA via hydrogen bond and π-cation interactions. [ABSTRACT FROM AUTHOR]