Inhibition of porcine pancreatic α-amylase activity by chlorogenic acid

The inhibitory mechanism of chlorogenic acid (CHA) against porcine pancreatic α-amylase (PPA) was examined by enzyme kinetic analysis, circular dichroism, fluorescence quenching and molecular docking. As a result, CHA showed a mixed-type inhibitory action on PPA, with the IC50 value of 0.498 ± 0.013 mg/mL. Analysis of fluorescence and circular dichroism spectra confirmed that CHA altered the secondary structure of PPA, by interacting with the amino acid residues around or distant from the catalytic site of PPA, mainly through hydrogen bonds, and this interaction was closely associated with the enzyme’s activity. Molecular docking indicated that the best pose between CHA and PPA was achieved with the binding energy of −7.8 and −7.2 kcal/mol at the active site and inactive site of PPA, respectively. The performed study reveals that CHA has the potential to inhibit the activity of α-amylase, thereby representing a novel idea to delay the digestion of starch.