Rapid identification of direct-acting pancreatic protectants from Cyclocarya paliurus leaves tea by the method of serum pharmacochemistry combined with target cell extraction

Extracts of Cyclocarya paliurus (CP) leaves, a popular sweet tea, inhibit pancreatic β cell apoptosis and have potent hypoglycemic effects, but the identities of the anti-apoptotic bioactive components are still unknown. In the present study, a method using UPLC-Q-TOF/MS based on serum pharmacochemistry combined with target cell extraction was established to rapidly identify direct-acting pancreatic protectants from CP. After orally administering a set amount of CP extract to rats, blood samples were collected to characterize the components that can be absorbed into the blood using UPLC-Q-TOF/MS. Also, target cells (pancreatic β NIT-1 cells) were incubated with CP extract for 24 hours, and cells were collected to identify the components that can bind to the cells using UPLC-Q-TOF/MS. Finally, to evaluate the protective effect of the bioactive components of CP, MTT and TUNEL assays were performed on treated NIT-1 cell induced by streptozotocin (STZ). Three potential direct-acting pancreatic protectants -- kaempferol, quercetin, quadranoside IV -- were identified, and anti-apoptotic effects of kaempferol and quercetin were confirmed in STZ-induced NIT-1 cells. The findings indicate that this combined approach is a feasible, rapid, and expedient tool for capturing potential direct-acting components from natural products such as those from CP leaves.