Blood glucose-lowering activity of protocatechuic acid is mediated by inhibiting <em>&amp;alpha;</em>-glucosidase

α-Glucosidase inhibitors are effective in controlling postprandial hyperglycemia, which play crucial roles the management of type 2 diabetes. Protocatechuic acid (PCA) is one phenolic acids existing not only various plant foods but also as a major microbial metabolite dietary anthocyanins large colon. The present study investigated inhibitory mechanism PCA on α-glucosidase in vitro and examined its effect blood glucose levels vivo. Results from experiments demonstrated that was mix-type inhibitor α-glucosidase. Driven by hydrogen bonds van der Waals interactions, reversibly bound with to form stable α-glucosidase-PCA complex spontaneous manner. computational simulation found could insert into active cavity establish catalytic amino residues. binding aroused steric hindrance for substrates enter sites caused structural changes interacted exhibited hypoglycemic capacity diabetic mice. This may provide theoretical basis application an ingredient functional