Rhizoma Anemarrhenae extract ameliorates hyperglycemia and insulin resistance via activation of AMP-activated protein kinase in diabetic rodents.

Abstract

ETHNOPHARMACOLOGICAL RELEVANCE:

Rhizoma Anemarrhenae has been used in Asian countries for thousands of years to treat diabetes. Insulin resistance (IR) is the primary cause responsible for type 2 diabetes. The aim of this study was to to assess the hypoglycemic and insulin sensitizing properties of Rhizoma Anemarrhenae extract (TFA) in animal models of insulin resistance and/or diabetes and to delineate modes of action.

MATERIALS AND METHODS:

In-vivo studies were performed on STZ-induced diabetic mice and KK-Ay mice, the former of which were given the extract alone or in combination with insulin for 7 days, and the latter of which were given the extract for 8 consecutive weeks. Fasting blood glucose and serum insulin levels were measured. Pancreatic tissue sections were examined using transmission electron micrographs. Further, hyperinsulinemic-euglycemic clamping study was conducted in BCG vaccine-induced insulin resistance rats, and glucose infusion rate was examined. Mechanisms of action were investigated in 3T3-L1 and Hela cells using Western blot analysis.

RESULTS:

Our study showed that TFA enhanced the glucose-lowering effects of exogenous insulin administration in STZ-induced diabetic mice. Therapeutic administration of TFA significantly reduced fasting blood glucose, and serum insulin levels, and markedly increased the size and the number of insulin-producing beta cells in KK-Ay mice. Further, hyperinsulinemic-euglycemic clamping study showed that glucose infusion rate was significantly improved in TFA-treated BCG vaccine-induced insulin resistance rats. Study of mechanism of action revealed that TFA increased phosphorylation of AMPK and its downstream target, acetyl-CoA carboxylase (ACC) in 3T3-L1 cells. It activates AMPK in a LKB1-independent manner, providing a unified explanation for the beneficial effects of TFA.

CONCLUSIONS:

This study that TFA mediates activation of AMPK and improves overall glucose and lipid metabolism in diabetic rodents, highlights the potential utility of TFA for the management of type 2 diabetes.

• Authors: Jun Han, Na Yang, Feng Zhang, Chuan Zhang, Fengying Liang, WeiFen Xie, Wansheng Chen
• Journal: Journal of ethnopharmacology (J Ethnopharmacol) Vol. 172 Pg. 368-76 (Aug 22 2015) ISSN: 1872-7573 [Electronic] Ireland
• PMID: 26162543 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Chemical References

• Blood Glucose
• Hypoglycemic Agents
• Insulin
• Plant Extracts
• AMP-Activated Protein Kinases

Topics

• 3T3-L1 Cells
• AMP-Activated Protein Kinases (metabolism)
• Anemarrhena (chemistry)
• Animals
• Blood Glucose (drug effects)
• Diabetes Mellitus, Experimental (drug therapy)
• Diabetes Mellitus, Type 2 (drug therapy)
• Female
• HeLa Cells
• Humans
• Hyperglycemia (drug therapy)
• Hypoglycemic Agents (isolation & purification, pharmacology)
• Insulin (blood)
• Insulin Resistance
• Lipid Metabolism (drug effects)
• Male
• Mice
• Mice, Inbred ICR
• Plant Extracts (pharmacology)
• Rats
• Rats, Sprague-Dawley
• Rhizome