Inhibition Effect and Molecular Mechanism of Tea Polyphenols on the α-Amylase

In present study, the inhibitory effect and molecular mechanism of tea polyphenols on α-amylase were investigated. With the determination of inhibition kinetics, the inhibition of tea polyphenols on α-amylase was estimated. Then, by using the fluorescence chromatography and circular dichroism, the changes of spatial structure and stability of α-amylase were observed. Furthermore, the molecular docking was used to explore the molecular interactions between tea polyphenols and α-amylase. The results showed that tea polyphenols exhibited the inhibitory effect on α-amylase with a half maximal inhibitory concentration of 1.35 mg/mL in a non-competitive manner. There was a fluorescence quenching effect of tea polyphenols on α-amylase with the red-shift of maximum emission wavelength (λ_max) in the fluorescence chromatography. Moreover, the secondary structure of α-amylase was found to change from the stratified structure to helical structure, which indicated the decreasing stability of α-amylase. By forming the hydrogen bond and hydrophobic interaction, tea polyphenols could bind to α-amylase as the stable complex which contributed to the decrease of enzyme activity. The results suggested that tea polyphenols had the potential value as α-amylase inhibitors.