Exploring the inhibitory mechanism of icaritin on α-glucosidase and synergistic effect with acarbose by inhibition kinetics, molecular docking, multi-spectroscopic methods and in vivo hypoglycemic model

Epimedii herba ( Epimedium spp.) is a medicinal and edible plant, and its main active ingredient is icaritin. This study investigates the inhibitory mechanism of icaritin against α-glucosidase and cooperates with acarbose to treat diabetes. Fluorescence quenching, synchronous fluorescence, CD spectroscopy, ANS fluorescence probe, and molecular docking results suggested that after the binding of icaritin. The internal fluorescence of α-glucosidase was statically quenched, and the microenvironment and conformation of α-glucosidase were altered by hydrogen bonding interaction. Interestingly, the combination of acarbose and icaritin exhibited a strong synergistic inhibitory effect. Oral glucose tolerance tests showed that icaritin and acarbose could synergistically reduce postprandial blood glucose (PBG) in mice. In summary, this study highlights the potential of Epimedii herba as a novel functional food for the prevention and management of type 2 diabetes, contributing to its development in nutraceutical applications. • Icaritin was a non-competitive inhibitor of α-glucosidase. • Icaritin and acarbose showed a synergistic inhibition effect on α-glucosidase. • Icaritin can alter the conformation and microenvironment of α-glucosidase. • The combination of icaritin and acarbose could significantly reduce PBG levels in mice.