Korean red ginseng stimulates insulin release from isolated rat pancreatic islets

Ethnopharmacological relevance: Korean red ginseng (KRG), one of heat-processed Korean ginseng (Panax ginseng C.A. Meyer), has a long history as herbal remedy for antidiabetic effect. Aim of the study: The effect and mechanism of KRG on stimulation of insulin release were investigated in isolated rat pancreatic islets. Material and methods: Pancreatic islets isolated from rats were used to evaluate the insulinotropic action of KRG. The effect of Ca on the insulinotropic action of KRG was investigated. Results: The aqueous ethanolic extract of KRG (AEE-KRG) (0.1-1.0 mg/ml) significantly evoked a stimulation of insulin release at 3.3 mM glucose compared to the control. Experiments at different glucose concentrations (8.4 and 16.7 mM) showed that AEE-KRG significantly stimulated on its own whereas it did not potentiate insulin secretion induced by glucose. The extracellular Ca2+-free condition, a L-type Ca2+ channel blocker and an ATP-sensitive K+ channel opener significantly inhibited insulin secretion evoked by AEE-KRG. Conclusion: These findings suggest that KRG displays beneficial effects in the treatment of diabetes at least in part via the stimulation of insulin release in a glucose-independent manner. (C) 2008 Elsevier Ireland Ltd. All rights reserved.