Evaluation of Antidiabetic Effects of the Traditional Medicinal Plant Gynostemma pentaphyllum and the Possible Mechanisms of Insulin Release. (23rd June 2015)

• Record Type: Journal Article
• Authors: Lokman, Ezarul Faradianna; Gu, Harvest F.; Wan Mohamud, Wan Nazaimoon; Östenson, Claes-Göran
• Other Names: Chan Shun-Wan Academic Editor.
• Is Part Of: Evidence-based complementary and alternative medicine. Volume 2015(2015)
• Publication Date: 2015-06-23
• Subjects: Alternative medicine -- Periodicals; 615.505
• DOI: 10.1155/2015/120572
• Languages: English
• ISSNs: 1741-427X

Abstract

Abstract : Aims . To evaluate the antidiabetic effects of Gynostemma pentaphyllum ( GP ) in Goto-Kakizaki (GK) rat, an animal model of type 2 diabetes, and to investigate the mechanisms of insulin release. Methods . Oral glucose tolerance test was performed and plasma insulin levels were measured. Results . An oral treatment with GP (0.3 g/kg of body weight daily) for two weeks in GK rats improved glucose tolerance versus placebo group (P < 0.01 ). Plasma insulin levels were significantly increased in the GP -treated group. The insulin release from GP -treated GK rats was 1.9-fold higher as compared to the control group (P < 0.001 ). GP stimulated insulin release in isolated GK rat islets at high glucose. Opening of ATP-sensitive potassium (K-ATP) channels by diazoxide and inhibition of calcium channels by nifedipine significantly decreased insulin response to GP . Furthermore, the protein kinase A (PKA) inhibitor H89 decreased the insulin response to GP (P < 0.05 ). In addition, GP -induced insulin secretion was decreased after preincubation of GK islets with pertussis toxin to inhibit exocytoticG e proteins (P < 0.05 ). Conclusion. The antidiabetic effect of GP is associated with the stimulation of insulin release from the islets. GP -induced insulin release is partly mediated via K-ATP and L-type Ca 2+ channels, the PKA system and also dependent on pertussis toxin sensitiveG e -protein.