Polyphenols from Flos Trollii inhibit α-amylase and α-glucosidase: Kinetic analysis and mechanistic insights

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. Integrated phytochemical and mechanistic studies elucidated Flos Trollii polyphenols as bifunctional inhibitors of α-amylase and α-glucosidase. • The phytochemical characterization of Flos Trollii polyphenols (FTP) was performed via UPLC−Q−TOF−MS E . • The inhibitory mechanisms of FTP on starch-digestive enzymes were systematically elucidated through enzyme kinetics, multi-spectroscopic analyses, and molecular docking. • FTP exhibited non-competitive inhibition against α-amylase and non-competitive inhibition against α-glucosidase, with superior inhibitory efficacy observed for α-glucosidase at comparable concentrations. • Linarin, vitexin, kaempferol-3-gentiobioside, and orientin were identified as the principal inhibitors of starch-digestive enzymes in the FTP.