Exploring the interaction of bavachin and its glycoside derivatives with bovine serum albumin using spectroscopic and molecular docking approaches

Bavachin (BVN) is a flavonoid extracted from the traditional Chinese medicine Psoralea corylifolia Linn. (P. corylifolia). BVNglu1-3 are three synthesised novel glycoside derivatives of bavachin with good water solubility. In this study, the interactions of BVN and BVNglu1-3 with bovine serum albumin (BSA) were explored using a combination of spectroscopy and molecular docking techniques. The experimental results showed that BVN and its glycoside derivatives (BVNs) formed stable complexes with BSA, leading to the intrinsic fluorescence quenching of BSA. BSA fluorescence quenching primarily occurred via the static mechanism. The binding constants of BVNs with BSA were in the order of BVN (2.66 x 10(5)) >> BVNglu2 (1.66 x 10(3)) > BVNglu1 (1.49 x 10(3)) > BVNglu3 (0.84 x 10(3)) at 298 K. The effects of the glycoside group number and position on binding affinity have been discussed. Analysis of the thermodynamic parameters demonstrated that the binding interactions of BVNs with BSA were spontaneous. BVN and its glycosides showed different modes of interaction forces when bound to BSA. Conformational experimental research revealed that the binding of the four compounds affected the secondary structure of BSA marginally. The site competition experiments and molecular docking studies showed that BVN and its glycosides did not share the same binding sites on BSA. (C) 2021 Elsevier B.V. All rights reserved.