Effect of beta-sitosterol-3-beta-D-glucoside on insulin secretion in vivo in diabetic rats and in vitro in isolated rat islets of Langerhans.

Beta-Sitosterol-3-beta-D-glucoside (1) has been reported to be the active antidiabetic agent of Centaurea seridis L. var. maritima. The present study examines the effect of oral administration of this compound on plasma insulin and glucose levels in streptozotocin-induced diabetic rats and its influence on insulin release from isolated rat islets. The results indicate that 1 did not change insulin and glucose levels in rats with severe diabetes. 1 stimulated insulin release from isolated rat islets in the presence of a non-stimulatory glucose concentration but did not increase the insulin releasing capacity of glucose (16 mmol/l). These data suggest that 1 exerts its action on intact pancreatic beta-cells by stimulating insulin secretion.