How Astragalin Modulates Glucose Uptake and Insulin Secretion in β-Cell Lines

Background/Objectives: Type 2 diabetes mellitus (T2DM) is characterized by chronic hyperglycemia and insulin resistance, leading to progressive metabolic dysfunction. Flavonoids, such as astragalin, have reported antidiabetic potential; however, their direct effects on pancreatic β-cell ionic mechanisms and insulin secretion remain unclear. This study aimed to investigate the effects of astragalin on glucose uptake, insulin secretion, and membrane ionic currents in pancreatic β-cell lines. Methods: Murine MIN6 and rat INS-1 pancreatic β-cells were used as experimental models. Following astragalin treatment, glucose uptake was quantified by bioluminescence, and insulin secretion was measured by ELISA. Ionic currents were analyzed using the whole-cell patch-clamp technique. Selective pharmacological blockers targeting ATP-sensitive K⁺ channels (KATP), voltage-dependent K⁺ channels (K_v), and L-type voltage-dependent Ca²⁺ channels were applied to elucidate the underlying mechanisms. Results: Astragalin increased glucose uptake in a time-dependent manner, reaching a plateau between 3 and 5 h. Insulin secretion was significantly enhanced after 1 h of exposure to 100 µM astragalin. Patch-clamp recordings demonstrated that astragalin reduced potassium channel currents in pancreatic β-cells. Pharmacological modulation confirmed the involvement of KATP, K_v, and L-type Ca²⁺ channels. Verapamil attenuated the insulinotropic effect, supporting the role of calcium influx in astragalin-induced insulin exocytosis. Conclusions: Astragalin enhances glucose uptake and stimulates insulin secretion in pancreatic β-cells through modulation of potassium and calcium channels, promoting calcium-dependent exocytosis. These findings support its potential as a candidate for antidiabetic therapeutic strategies.