Molecular insights into α‐glucosidase inhibition and antiglycation properties affected by the galloyl moiety in (−)‐epigallocatechin‐3‐gallate

Abstract

AbstractBACKGROUNDDiabetes mellitus poses a substantial threat to public health due to rising morbidity and mortality. α‐Glucosidase is one of the key enzymes affecting diabetes. Herein, (−)‐epigallocatechin‐3‐gallate (EGCG) and (−)‐epigallocatechin (EGC) were applied to clarify the role of the galloyl moiety of tea polyphenols in the inhibition of glycation and α‐glucosidase activity. The structure–activity relationship of the galloyl moiety in EGCG on α‐glucosidase was investigated in terms of inhibition kinetics, spectroscopy, atomic force microscopy and molecular docking. A bovine serum protein–fructose model was employed to determine the effect of the galloyl moiety on glycation.RESULTSThe results indicated that the introduction of a galloyl moiety enhanced the capacity of EGCG to inhibit glycation and α‐glucosidase activity. The IC50 value of EGC is approximately 2400 times higher than that of EGCG. Furthermore, the galloyl moiety in EGCG altered the microenvironment and secondary structure of α‐glucosidase, resulting in a high binding affinity of EGCG to α‐glucosidase. The binding constant of EGCG to α‐glucosidase at 298 K is approximately 28 times higher than that of EGC.CONCLUSIONOverall, the galloyl moiety of EGCG plays a crucial role in inhibiting glycation and α‐glucosidase activity, which helps to enhance the molecular understanding of the structure and function of the polyphenol galloyl moiety in the science of food and agriculture. © 2023 Society of Chemical Industry.