The interaction of piperine with bovine serum albumin (BSA) was investigated by fluorescence and absorption spectra in combination with molecular modeling under the simulated physiological conditions. The binding constants and the number of binding sites between piperine and BSA at different temperatures (298, 308 and 318 K) were calculated according to the data obtained from fluorescence titration. The results of spectroscopic measurements and the thermodynamic parameters obtained (the enthalpy change ΔHӨ and the entropy change ΔSӨ were calculated to be －9.55 kJ•mol－1 and 46.75 J•mol－1•K－1 according to the Van’t Hoff equation) suggested that hydrophobic and electrostatic interaction be the predominant intermolecular forces stabilizing the complex. Molecular docking was performed to reveal the possible binding mode or mechanism, suggesting that piperine can strongly bind to BSA. Under the conditions studied, the values of the negative charge density (δ), the dissociation constants (Kd) and quantum yield (F) of piperine-BSA system were calculated.

Key words: piperine, bovine serum albumin (BSA), interaction, fluorescence spectroscopy, molecular modeling