Inhibition mechanism of ferulic acid against α-amylase and α-glucosidase

The inhibitory mechanisms of ferulic acid against α-amylase and α-glucosidase were investigated by enzyme kinetic analysis, circular dichroism (CD), Fourier-transform infrared (FT-IR) spectroscopy, fluorescence quenching and molecular docking. Results indicated that ferulic acid strongly inhibited α-amylase (IC 50 : 0.622 mg ml −1 ) and α-glucosidase (IC 50 : 0.866 mg ml −1 ) by mixed and non-competitive mechanisms, respectively. CD spectra and fluorescence intensity measurements confirmed that the secondary structure of α-amylase and α-glucosidase were changed and the microenvironments of certain amino acid residues were modulated by the binding of ferulic acid. FT-IR spectra indicated that the interaction between ferulic acid and α-amylase/α-glucosidase mainly involved in non-covalent bonds. Molecular docking further demonstrated that the interaction forces between ferulic acid and α-amylase/α-glucosidase were hydrogen bonds, with the binding energy of −5.30 to −5.10 and −5.70 kcal mol −1 , respectively. This study might provide a theoretical basis for the designing of novel functional foods with ferulic acid.