Astragalin augments basal calcium influx and insulin secretion in rat pancreatic islets

Astragalin is a flavonol glycoside with several biological activities, including antidiabetic properties. The objective of this study was to investigate the effects of astragalin on glycaemia and insulin secretion, in vivo, and on calcium influx and insulin secretion in isolated rat pancreatic islets, ex vivo. Astragalin (1 and 10 mg / kg) was administered by oral gavage to fasted Wistar rats and serum glucose and plasma insulin were measured. Isolated pancreatic islets were used to measure basal insulin secretion and calcium influx. Astragalin (10 mg/ kg) decreased glycaemia and increased insulin secretion significantly at 15–180 min, respectively, in the glucose tolerance test. In isolated pancreatic cells, astragalin (100 μM) stimulated calcium influx through a mechanism involving ATP-dependent potassium channels, L-type voltage-dependent calcium channels, the sarcoendoplasmic reticulum calcium transport ATPase (SERCA), PKC and PKA. These findings highlight the dietary coadjuvant, astragalin, as a potential insulin secretagogue that may contribute to glucose homeostasis.