Document Detail


20(S)-ginsenoside Rg3 enhances glucose-stimulated insulin secretion and activates AMPK.
MedLine Citation:
PMID:  18379076     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Although Panax ginseng has been widely used in oriental countries for pharmacological effects such as anti-diabetic, anti-inflammatory, adaptogenic and anti-fatigue activities, the active ingredient is not yet fully identified. In our preliminary studies, protopanaxadiol ginsenosides showed the insulin secretion-stimulating activity. In HIT-T15 cells, Rg3 enhanced the insulin secretion in a concentration dependent manner. This effect, however, was almost completely abolished in the presence of diazoxide (K+ channel opener) or nifedipine (Ca2+ channel blocker). Oral glucose tolerance test (OGTT) was also performed using ICR mice and Rg3 suppressed the blood glucose levels from rising by enhancing an insulin secretion at 30 min after administration. From these studies, we may conclude that Rg3 lowered the plasma glucose level by stimulating an insulin secretion and this action was presumably associated with ATP sensitive K+ channel. Next, to explore the hypothesis that ginsenoside Rg3 epimers may exhibit differential effects, glucose-stimulated insulin secretion activity and phosphorylation of AMP-activated protein kinase (AMPK) were compared between 20(S)- and 20(R)-ginsenoside Rg3. 5 microM of 20(S)-Rg3 enhanced the glucose-stimulated insulin secretion by 58% compared to the control, but 20(R)-Rg3 did not show any effect. In C2C12 myotubes, 20(S)- and 20(R)-Rg3 both markedly phosphorylated AMPK and acetyl-CoA carboxylase (ACC), although 20(R)-Rg3 showed a little less effect. Taken together, our results suggest that ginsenoside Rg3 epimers showed differential activities, and 20(S)-Rg3 epimer exhibited the higher pharmacological effects in insulin secretion and AMPK activation than 20(R)-Rg3. The novel characteristics of 20(S)-Rg3 may be a valuable candidate for anti-diabetic agent.
Authors:
Min Woo Park; Joohun Ha; Sung Hyun Chung
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biological & pharmaceutical bulletin     Volume:  31     ISSN:  0918-6158     ISO Abbreviation:  Biol. Pharm. Bull.     Publication Date:  2008 Apr 
Date Detail:
Created Date:  2008-04-01     Completed Date:  2008-05-12     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  9311984     Medline TA:  Biol Pharm Bull     Country:  Japan    
Other Details:
Languages:  eng     Pagination:  748-51     Citation Subset:  IM    
Affiliation:
Department of Life and Nanopharmaceutical and Department of Pharmaceutical Science, Kyung Hee University, Seoul130-701, Korea.
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MeSH Terms
Descriptor/Qualifier:
Animals
Blotting, Western
Cell Line
Cricetinae
Cyclic AMP-Dependent Protein Kinases / metabolism*
Enzyme Activation / drug effects
Ginsenosides / chemistry,  pharmacology*
Glucose / pharmacology*
Glucose Tolerance Test
Hypoglycemic Agents*
Insulin / secretion*
Lipid Metabolism / drug effects
Male
Mice
Mice, Inbred ICR
Muscle Fibers, Skeletal / drug effects
Stimulation, Chemical
Chemical
Reg. No./Substance:
0/Ginsenosides; 0/Hypoglycemic Agents; 11061-68-0/Insulin; 14197-60-5/ginsenoside Rg3; 50-99-7/Glucose; EC 2.7.11.11/Cyclic AMP-Dependent Protein Kinases

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