Antioxidant and protective effects of major flavonoids from Teucrium polium on beta-cell destruction in a model of streptozotocin-induced diabetes.

The hypoglycemic effect of Teucrium polium has been accounted for by its constituents that increase insulin release. The present study aimed to investigate whether the major flavonoid compounds (rutin and apigenin) from the methanol extract of Teucrium polium would stimulate insulin secretion and, if so, to further elucidate the mechanism behind this effect. Isolated rat pancreatic islets were batch incubated to study the effect of rutin and apigenin on insulin secretion at various glucose concentrations. Treated islets in the presence of streptozotocin (STZ) and flavonoid compounds significantly increased insulin release by almost 56 % compared with STZ-treated islets. Our data indicated that the flavonoids in T. polium extract appeared to be helpful in protecting pancreatic islets against exposure to STZ in vitro due to their antioxidant activity. Georg Thieme Verlag KG Stuttgart-New York.