Inhibition mechanism of diacylated anthocyanins from purple sweet potato (Ipomoea batatas L.) against α-amylase and α-glucosidase

Food Chem. 2021 Oct 15;359:129934. doi: 10.1016/j.foodchem.2021.129934. Epub 2021 Apr 23.

Abstract

This study aimed to evaluate inhibitory activity of anthocyanins from purple sweet potato and blueberries against α-amylase and α-glucosidase, as well as investigate the inhibition mechanism of diacylated anthocyanins (Diacylated AF-PSP). Diacylated AF-PSP better inhibited α-amylase (IC50 = 0.078 mg mL-1) and α-glucosidase (IC50 = 1.56 mg mL-1) than other anthocyanin fractions, which was a mixed-type inhibitor. Fluorescence analysis indicated that Diacylated AF-PSP bound to the enzymes mainly through hydrogen bonds and influenced the microenvironments of proteins. Additionally, surface hydrophobicity and circular dichroism spectra results confirmed conformational changes in the enzymes induced by Diacylated AF-PSP. Molecular docking further demonstrated the interaction of Diacylated AF-PSP with enzyme active site, which might be stabilized by its acyl groups. Finally, 160 mg kg-1 Diacylated AF-PSP significantly decreased (p < 0.01) blood glucose level peak by 20.52% after starch administration in SD rats. This study provided theoretical evidences for utilization of diacylated anthocyanins in hyperglycemia-management functional foods.

Keywords: Diacylated anthocyanins; Inhibition mechanism; Molecular docking; Postprandial hyperglycemia; Starch digestive enzymes.

MeSH terms

  • Animals
  • Anthocyanins / pharmacology*
  • Enzyme Inhibitors / pharmacology*
  • Ipomoea batatas / chemistry*
  • Male
  • Molecular Docking Simulation
  • Rats
  • Rats, Sprague-Dawley
  • Starch / metabolism
  • alpha-Amylases / antagonists & inhibitors*
  • alpha-Glucosidases / drug effects*

Substances

  • Anthocyanins
  • Enzyme Inhibitors
  • Starch
  • alpha-Amylases
  • alpha-Glucosidases