Polyphenols from Flos Trollii inhibit α-amylase and α-glucosidase: Kinetic analysis and mechanistic insights
Xiaoai Zhu, Kebing Yan, X. Ye, Xia Xiang, Yu Ru, Yiying Niu, Yage Liu, Jun Xi, Kunlun Liu
Abstract
ABSTRACT The increasing global prevalence of type 2 diabetes mellitus (T2DM) necessitates natural agents that target α-amylase and α-glucosidase to modulate starch digestion. Although Flos Trollii is a well-documented phytomedicine, its enzymatic inhibition profile remains understudied, particularly with respect to starch-digesting enzymes. This study employed an integrated approach combining UPLC−Q−TOF−MS E , enzyme kinetic, multispectral, and molecular docking simulations to elucidate the inhibitory mechanism of Flos Trollii polyphenols (FTP) on starch-digesting enzymes. UPLC−Q−TOF−MS E identified 10 major polyphenolic compounds. Kinetic analyses indicated that FTP inhibited α-amylase in mixed mode (IC 50 =67.70±9.67 μg·mL −1 ) and α-glucosidase in noncompetitive mode (IC 50 =36.13±0.23 μg·mL −1 ). FTP induced dynamic fluorescence quenching, resulting in the formation of enzyme-inhibitor complexes stabilized through hydrogen bonding, van der Waals interactions, and hydrophobic effects. Spectroscopic evidence confirmed that FTP binding triggered shifts in the enzyme structure, ultimately hampering its activity, whereas molecular docking further identified the specific binding sites. This study highlighted the potential of FTP as a nutraceutical for T2DM management.