Inhibitory interaction of narcissoside on α-glucosidase from Aspergillus niger and Saccharomyces cerevisiae by spectral analysis and molecular docking

Inhibition of α-glucosidase was an effective method to control postprandial hyperglycemia due to it could reduce postprandial hyperglycemia. Narcissoside was a natural flavonoid with anti-diabetic effect, however, the inhibitory interaction of α-glucosidase by narcissoside were not reported. The inhibition interaction of narcissoside on the two sources of α-glucosidase from Aspergillus niger (A. niger) (ANG) and Saccharomyces cerevisiae (S. cerevisiae) (SCG) were explored based on spectral analysis coupled with molecular docking in this study. The fluorescence analysis suggested that the ANG and SCG were statically quenched by narcissoside. Meanwhile, narcissoside was bound to ANG more strongly than it did to SCG at the same temperature. Spectral analysis indicated that the conformation of ANG and SCG were altered after binding to narcissoside. The homologous protein of ANG and SCG were constructed to obtain accurate docking results, and the result confirmed that narcissoside occupied the active region of ANG and SCG by hydrogen bond and Van der Waals force. Thereby, narcissoside might be a potentially active ingredient for the prevention or treatment of Type 2 diabetes.