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

The inhibitory mechanisms of ferulic acid against alpha-amylase and alpha-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 in(h)ibited alpha-amylase (IC50: 0.622 mg ml(-1)) and alpha-glucosidase (IC50: 0.866 mg ml(-1)) by mixed and non-competitive mechanisms, respectively. CD spectra and fluorescence intensity measurements confirmed that the secondary structure of aamylase and alpha-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 alpha-amylase/alpha-glucosidase mainly involved in non-covalent bonds. Molecular docking further demonstrated that the interaction forces between ferulic acid and alpha-amylase/alpha-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.