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International Journal of Experimental Diabetes Research
Volume 2 (2001), Issue 2, Pages 91-99
http://dx.doi.org/10.1155/EDR.2001.91

In Vitro Effect of Fenugreek Extracts on Intestinal Sodium-dependent Glucose Uptake and Hepatic Glycogen Phosphorylase A

1Department of Clinical Biochemistry, University of Sana'a, Sana'a, Yemen
2Department of Pharmacy, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 8WA, UK
3Institute of Biomedical and Life Sciences, West Medical Building, University of Glasgow, Glasgow G12 8QQ, UK

Received 9 March 2001; Accepted 25 April 2001

Copyright © 2001 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Fenugreek (Trigonella foenum-graecum L. seed) is a food with traditional medicinal use in diabetes. Beneficial effects have been demonstrated in diabetic animals and both insulin-dependent and non-insulin-dependent diabetic subjects. Effects of a lipid extract A, crude ethanolic extract B, further sub-fractions of B (saponin-free C, saponin D and sapogenin E) and a gum fibre fraction F on intestinal sodium-dependent glucose uptake were investigated in vitro using rabbit intestinal brush border membrane vesicles. All fractions except A inhibited glucose-uptake at 0.33 and/or 3.3mg/mL (p < 0.001). Greatest inhibition was observed with fractions D and E. Diosgenin and trigonelline (compounds reported in fenugreek)also inhibited glucose-uptake (IC50 values approximately 3mg/ ml, equivalent to 8mM and 19mM respectively) but did not account for the activity of the crude extracts. Fenugreek extracts had no effect on basal levels of glycogen phosphorylase a (HGPa) activity in rat hepatocyte suspensions. However fractions C and E caused a marginal but statistically significant inhibition (18.9 and 15.1% respectively, p < 0.05) of glucagon induction of this enzyme suggesting a glucagon-antagonist effect. Diosgenin (1.65mg/ml; 4mM) inhibited glucagon-induced HGPa activity by 20% (p < 0.05), and was more effective than trigonelline (non significant inhibition of 9.4% at 1.65mg/ml, 10mM).