An investigation of the inhibitory mechanism of α-glucosidase by chysalodin from Aloe vera.

The aim of our study is to provide new type skeleton of α-glucosidase inhibitor from food source. A new 6'-O-(E)-cinnamoyl-7-methoxy-aloin A (1) was isolated from Aloe vera. Also, known chysalodin (2) was the first report for A. vera. These structures were identified with based on HR-ESI Mass and 1/2D-NMR spectra. These isolated compounds were tested for their inhibitory activities against α-glucosidase by using spectrophotometer. Of these, compound 2 exhibited inhibitory activity, with an IC50 value of 13.4 ± 1.5 μM. An enzyme kinetic study identified the mechanism of binding of the ligand with the enzyme; the ligand binds in the active site of the enzyme in a competitive mode. Additionally, fluorescence quenching between the ligand and receptor revealed a two-to-one reaction. Finally, this finding provides that anthraquinone dimer (2) could be a starting point for the design of new class of α-glucosidase inhibitor.