Description

Rehmannia Glutinosa Libosch extract. Synonym: Catalpinoside CAS: ********9 M.W.: **2.**9 Formula: C*5H*2O*0 Introduction: Catalpol is an iridoid glucoside that is found in plants belonging to several familie. Catalpol, a monoterpene compound , was isolated from Radix Rehmanniae (Dihuang). Rehmanniae Root is the fresh or dried root tuber of Rehmannia glutinosa Libosch. (Fam. Scrophulariaceae). The root tubers are dug up in autumn, removed from crowns, fibrous roots and soil, used eithner in the fresh state or baked to be nearly dry. The former is known as �Fresh Rehmanniae Root (Xian Dihuang) � and the latter is known as �Unprepared Rehmanniae Root (Sheng Dihuang)�. Fresh Rehmanniae Root is used to remove heat and promote the production of body fluid, to reduce heat in blood, and to arrest bleeding. Catalpol produced a dose-dependent hypoglycemic action in streptozotocin -induced diabetic rats after an intravenous injection (i.v.). Catalpol at the effective dose (0.1mg/kg) significantly attenuated the increase of plasma glucose induced by intravenous glucose challenge test in Wistar rats. In vitro, catalpol enhanced the uptake of *4C *-deoxy-glucose (*-DG) into skeletal muscle in a concentration-dependent manner. In the hepatocytes isolated from diabetic rats, catalpol also increased the synthesis of glycogen. Catalpol enhanced the uptake of radioactive glucose into mouse myoblast cell line C2C*2 cells in a dose-dependent manner, which was abolished by α*-adrenoceptor(α*-AR) blocker prazosin and α1A-AR blocker RS****3 pretreatment. Effect of catalpol on α*-AR was further supported by the displacement of [3H] prazosin binding in C2C*2 cells. The plasma glucose lowering effect of catalpol in the STZ-diabetic rats was also abolished by the pretreatment with prazosin and RS****3. Pharmacological inhibition of phospholipase C (PLC) by U****2 resulted in a concentration-dependent decrease in catalpol-stimulated uptake of radioactive glucose into C2C*2 cells, although, the