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United States Department of Agriculture

Agricultural Research Service

Research Project: Rice as a Source and Delivery System for Nutrients and Lipophilic Bioactive Compounds

Location: Food Processing and Sensory Quality Research

Title: Glyceollins, soy isoflavone phytoalexins, improve oral glucose disposal by stimulating glucose uptake

Authors
item Boue, Stephen
item Isakova, Irina -
item Burow, Matthew -
item Cao, Heping
item Bhatnagar, Deepak
item Sarver, Jeff -
item Shinde, Kamlesh -
item Erhardt, Paul -
item Heiman, Mark -

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 9, 2012
Publication Date: June 1, 2012
Citation: Boue, S.M., Isakova, I.A., Burow, M., Cao, H., Bhatnagar, D., Sarver, J., Shinde, K.V., Erhardt, P., Heiman, M. 2012. Glyceollins, soy isoflavone phytoalexins, improve oral glucose disposal by stimulating glucose uptake. Journal of Agricultural and Food Chemistry. 60(25):6376-6382.

Interpretive Summary: A mixture soy compounds called glyceollins are synthesized in response to environmental stresses such as microbial infections. Glyceollins exhibited anti-cancer and anti-diabetes effects: previously we showed that glyceollins inhibited cancer cell growth in cell and animal studies. In the present study we used pre-diabetic rat to examine how the glyceollins’ regulate blood glucose. Animals treated with glyceollins showed improved removal of glucose. Exposure of the isolated fat cells to the glyceollins significantly increased glucose uptake. Basal (without insulin) glucose uptake was increased 1.5-fold by exposure to glyceollin. Co-incubation with insulin significantly (p<0.05) stimulated maximal glucose uptake but glyceollins did not alter the potency of insulin. Gene expression analysis showed increased levels of glucose transporter genes in adipocytes treated with glyceollins. Thus the stimulative effect of the glyceollins on glucose removal was attributed to stimulation of two glucose transporter genes. These findings indicate potential benefits of the glyceollins for treating pre-diabetic conditions, type 1 and type 2 diabetes.

Technical Abstract: Glyceollins (glyceollin I, II, and III), isoflavone phytoalexins synthesized by soy in response to environmental stresses such as microbial infections. Glyceollins exhibited anti-cancer and anti-diabetes effects: previously we showed that glyceollins inhibited cancer cell growth in vitro and in vivo. In the present study we used pre-diabetic ZDSD rats to examine how the glyceollins’ regulate blood glucose. The blood glucose excursion during 2h following an oral glucose tolerance test (OGTT) significantly decreased in the rats treated with 30 mg/kg (n=8) or 90 mg/kg (n=8) glyceollins 1h prior to the glucose challenge compared to the vehicle treated animals (n=8). Exposure of the adipocytes to the glyceollins significantly (p<0.05) increased both insulin-stimulated and basal glucose uptake. Basal glucose uptake was increased 1.5-fold by exposure to 5µM glyceollin in a dose-response manner with an EC50 of 2.40 ± 0.43 µM and a maximal uptake of 2.04 ± 0.24–fold above basal glucose uptake (n=4). Co-incubation with insulin significantly (p<0.05) stimulated maximal glucose uptake but glyceollins did not alter the potency of insulin. Quantitative real-time PCR showed increased levels of both Glut1 and Glut4 glucose transporter genes in adipocytes treated with 5 µM to 10 µM glyceollins for 3h. Thus the stimulative effect of the glyceollins on adipocyte glucose uptake was attributed to up-regulation of the glucose transporters GLUT1 and GLUT4. These findings indicate potential benefits of the glyceollins for treating pre-diabetic conditions, type 1 and type 2 diabetes by increasing the insulin-mediated and basal, insulin-independent, glucose uptake by adipocytes.

Last Modified: 12/22/2014
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