Open AccessEffects of (-)-epigallocatechin gallate and quercetin on the activity and structure of α-amylase
Author(s) -
Jianhui Su,
Zhe Tang
Publication year - 2021
Publication title -
tropical journal of pharmaceutical research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.209
H-Index - 36
eISSN - 1596-5996
pISSN - 1596-9827
DOI - 10.4314/tjpr.v18i3.20
Subject(s) - quercetin , chemistry , epigallocatechin gallate , ic50 , flavonoid , amylase , gallate , in vitro , biochemistry , food science , polyphenol , enzyme , nuclear chemistry , antioxidant
Purpose: To investigate the effects of (-)-epigallocatechin gallate (EGCG) and quercetin on the activity and structure of α-amylase.
Methods: The inhibitory effects of 7 functional factors were compared by measuring half maximal inhibitory concentration (IC50) values. Lineweaver-Burk plots were used to determine the type of inhibition exerted by EGCG and quercetin against α-amylase. The effect of EGCG and quercetin on the conformation of α-amylase was investigated using fluorescence spectroscopy.
Results: Quercetin and EGCG inhibited α-amylase with IC50 values of 1.36 and 0.31 mg/mL, respectively, which were much lower than the IC50 values of the other compounds (puerarin, paeonol, konjac glucomannan and polygonatum odoratum polysaccharide). The Lineweaver−Burk plots indicated that EGCG and quercetin inhibited α-amylase competitively, with ki values of 0.23 and 1.28 mg/mL, respectively. Fluorescence spectroscopy revealed that treatment with EGCG and quercetin led to formation of a loosely-structured hydrophobic hydration layer.
Conclusion: This study has unraveled the mechanism underlying the inhibition of α-amylase activity by EGCG and quercetin in vitro. This should make for better understanding of the mechanisms that underlie the antidiabetic effects of EGCG and quercetin in vivo.