Identification of α-Glucosidase-Inhibitors in Edgeworthia gardneri (Wall.) Meisn. Using UPLC-Q-TOF-MS/MS Analysis.

Edgeworthia gardneri (Wall.) Meisn., a member of the genus Edgeworthia in the family Thymelaeaceae, has long been applied as an edible and medicinal plant in China. E. gardneria has a hypoglycemic effect and is used to prepare daily drinks for the prevention and treatment of diabetes. However, the hypoglycemic substances involved remain unknown. The present study aimed to screen the α-glucosidase-inhibitors of E. gardneri and analyze its chemical profile using a ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS) method. As a result, the ethyl acetate fraction (EAF) had significant α-glucosidase-inhibitory and antioxidant activities but did not show an α-amylase-inhibitory activity. A total of 67 compounds were identified in the EAF by UPLC-Q-TOF-MS/MS analysis; among them, 48 compounds were first discovered in the genus Edgeworthia. Additionally, five flavonoids, namely, isoorintin, secoisolaricirinol, tiliroside, chrysin, and kaempferol, had α-glucosidase-inhibitory activities. Rutin had a α-amylase-inhibitory activity. Daphnoretin, a kind of coumarin, has α-glucosidase and α-amylase-inhibitory activities. These findings enrich the chemical library of E. gardneria. EAF has a selective α-glucosidase-inhibitory activity, and flavonoids and coumarins may be the active components of EAF. E. gardneria has important value for developing multiple-target hypoglycemic drugs.