Α-glucosidase inhibitor isolated from coffee

J Microbiol Biotechnol. 2015 Feb;25(2):174-7. doi: 10.4014/jmb.1411.11057.

Abstract

The potent α-glucosidase inhibitor (compound I) was isolated from coffee brews by the activity-based fractionation and identified as a β-carboline alkaloid norharman (9H-pyrido[ 3.4-b]indole) on the basis of mass spectroscopy and nuclear magnetic resonance spectra ((1)H NMR, (13)C NMR, and COSY). The norharman showed a potent inhibition against α-glucosidase enzyme in a concentration dependent manner with an IC50 value of 0.27 mM for maltase and 0.41 mM for sucrase, respectively. A Lineweaver-Burk plot revealed that norharman inhibited α-glucosidase enzyme uncompetitively, with a Ki value of 0.13 mM.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbolines / metabolism*
  • Coffee / chemistry*
  • Glycoside Hydrolase Inhibitors / chemistry*
  • Glycoside Hydrolase Inhibitors / isolation & purification*
  • Glycoside Hydrolase Inhibitors / pharmacology
  • Hypoglycemic Agents / chemistry
  • Hypoglycemic Agents / isolation & purification
  • Hypoglycemic Agents / pharmacology
  • Magnetic Resonance Spectroscopy
  • Mass Spectrometry
  • Sucrase / antagonists & inhibitors
  • alpha-Glucosidases / metabolism*

Substances

  • 9H-pyrido(3.4-b)indole
  • Carbolines
  • Coffee
  • Glycoside Hydrolase Inhibitors
  • Hypoglycemic Agents
  • alpha-Glucosidases
  • Sucrase