Molecular Spectroscopy Evidence of Effective Constituents in the Binding of Angelica sinensis to Bovine Serum Albumin: Comparative Binding and Thermodynamic Profile

Some bio-effective constituents, such as organic acids and phthalides, from the root of Angelica sinensis can be observed in the blood after oral intake. In this work, two organic acids, ferulic acid and anisic acid, and two phthalides, senkyunolide I and butylidenephthalide, were selected to investigate the interaction with bovine serum albumin systematically, using a fluorescence spectroscopic method under physiological conditions. The Stern–Volmer quenching constant, binding constant, and the corresponding thermodynamic parameters and binding numbers were measured. Synchronous fluorescence and three-dimensional fluorescence spectroscopy were also used. The results provided molecular spectroscopy evidence that some constituents of Angelica sinensis are absorbed and transported into the blood.