Document Detail


Long-term consumption of saponins derived from Platycodi radix (22 years old) enhances hepatic insulin sensitivity and glucose-stimulated insulin secretion in 90 % pancreatectomized diabetic rats fed a high-fat diet.
MedLine Citation:
PMID:  18577298     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Crude saponins derived from Chinese Platycodi radix have been reported to prevent increases in body weight and liver TAG in mice fed a high-fat diet. We investigated the effects of an extract (PR) taken from Korean Platycodi radix, which is cultivated for 22 years in the ground (Jangsaeng doraji), and its saponins (PRS) on insulin resistance and glucose-stimulated insulin secretion in 90 % pancreatectomized diabetic rats fed high-fat diets. Four groups were orally supplemented with 2 g PR, 0.2 g PRS, 20 mg rosiglitazone (positive control) or 0.5 g cellulose (negative control) per kg body weight on a daily basis for 8 weeks. We found that PRS lowered body weight, visceral fat mass and serum leptin levels in pancreatectomized rats in comparison to the control. PR enhanced first- and second-phase insulin secretion while PRS stimulated only first-phase insulin secretion. Glucose infusion rates to maintain euglycaemia at hyperinsulinaemic states decreased in a descending order of rosiglitazone, PRS, PR and control, but they increased hepatic glucose output in the same order. This reduction was associated with the storage of decreased TAG and increased glycogen, which was a result of enhanced tyrosine phosphorylation of anti-insulin receptor substrate-2 and serine473 phosphporylation of protein kinase B (PKB, Akt). Improved hepatic insulin signalling led to decreased phosphoenolpyruvate carboxykinase expression and reduced hepatic glucose output accordingly. In conclusion, PRS principally improves glucose homeostasis by enhancing hepatic insulin sensitivity as a consequence of reducing fat storage and stimulating insulin signalling in diabetic rats. In addition, PR contains components that promote glucose-stimulated insulin secretion.
Authors:
Dae Yeon Kwon; Young Seob Kim; Sang Mee Hong; Sunmin Park
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-06-25
Journal Detail:
Title:  The British journal of nutrition     Volume:  101     ISSN:  1475-2662     ISO Abbreviation:  Br. J. Nutr.     Publication Date:  2009 Feb 
Date Detail:
Created Date:  2009-01-12     Completed Date:  2009-06-11     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0372547     Medline TA:  Br J Nutr     Country:  England    
Other Details:
Languages:  eng     Pagination:  358-66     Citation Subset:  IM    
Affiliation:
Food Functional Research Division, Korean Food Research Institutes, Sungnam 463-746, Korea.
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Glucose / metabolism
Diabetes Mellitus, Experimental / metabolism*
Dietary Fats / administration & dosage*
Glucose / pharmacology
Homeostasis
Hypoglycemic Agents / pharmacology
Insulin / secretion
Insulin Resistance
Insulin-Secreting Cells / secretion
Korea
Liver / metabolism*
Male
Pancreatectomy
Plant Extracts / administration & dosage*
Platycodon / chemistry*
Rats
Rats, Sprague-Dawley
Saponins / administration & dosage*
Thiazolidinediones / pharmacology
Time Factors
Chemical
Reg. No./Substance:
0/Blood Glucose; 0/Dietary Fats; 0/Hypoglycemic Agents; 0/Plant Extracts; 0/Saponins; 0/Thiazolidinediones; 11061-68-0/Insulin; 122320-73-4/rosiglitazone; 50-99-7/Glucose

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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