Inhibitory mechanism of chrysin and diosmetin to α-glucosidase: insights from kinetics, multispectroscopy and molecular docking investigations

Abstract

Inhibition of α-glucosidase activity is a promising method to prevent postprandial hyperglycemia. The inhibitory effect and interaction of chrysin and diosmetin on α-glucosidase were studied in this study. The results of inhibition kinetics showed that chrysin and diosmetin reversibly inhibited α-glucosidase activity with IC₅₀ value of 26.445 ± 1.406 μmol L⁻¹ and 18.380 ± 1.264 μmol L⁻¹, respectively. Further research revealed that chrysin exhibited a mixed-type inhibitory pattern against α-glucosidase, while diosmetin was noncompetitive inhibitory with Ki value of (2.6 ± 0.04) ×10⁻⁴mol L⁻¹. Fluorescence spectroscopy showed that both chrysin and diosmetin could quench the intrinsic fluorescence of α-glucosidase, the maximum emission wavelength of tyrosine (Tyr) and tryptophan (Trp) were not moved by chrysin, but red shifted by diosmetin. UV-Vis, fourier transform infrared spectroscopy (FT-IR) and circular dichroism (CD) measurements showed that the secondary structure and microenvironment of α-glucosidase were changed by chrysin and diosmetin. Further analysis of molecular docking showed that chrysin and diosmetin could bind with α-glucosidase and might cause the decrease of α-glucosidase activity. The results of molecular dynamics (MD) simulation showed that the stability of chrysin (or diosmetin)-α-glucosidase complex system was changed during binding process. In conclusion, chrysin and diosmetin are good α-glucosidase inhibitors.

Communicated by Ramaswamy H. Sarma

Keywords:

• α-glucosidase
• chrysin
• diosmetin
• inhibitory mechanism
• molecular docking

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.