Comparative analysis of 1-deoxynojirimycin contribution degree to α-glucosidase inhibitory activity and physiological distribution in Morus alba L

•1-Deoxynojirimycin (DNJ), the main hypoglycemic constituents in mulberry, has been extensively researched.•The possible pathway of metabolism and storage of DNJ in mulberry was analyzed.•The inhibition kinetics of α-glucosidase by DNJ and ethanol extracts has been reported.•The relationship between DNJ content and α-glucosidase inhibitory activity in mulberry ethanol extracts have been reported.•This work provides useful informations for the development and utilization of crude drug resources of mulberry.