Nutr Res Pract.  2007 Dec;1(4):266-272.

Soybean isoflavone extract improves glucose tolerance and raises the survival rate in streptozotocin-induced diabetic rats

• Shim JY
• Kim KO
• Seo BH
• Lee HS

Abstract

The present study evaluated the effect of various dosages of soybean isoflavone extract on body weight changes, glucose tolerance and liver function in streptozotocin-induced diabetic rats. One group of normal rats (normal control) was fed an AIN-76-based experimental diet and four groups of diabetic rats were fed the same diet supplemented with four different levels of soybean isoflavone extract for seven weeks. The daily dosages of pure isoflavone for four diabetic groups were set to be 0 mg (diabetic control), 0.5 mg (ISO-I), 3.0 mg (ISO-II) and 30.0 mg (ISO-III) per kilogram of body weight, respectively. The daily consumption of isoflavone at the level of 3.0mg per kilogram of body weight resulted in the suppression of body weight loss and increased the survival rate of diabetic animals one and half times compared to that of the diabetic control group. Blood glucose levels in a fasting state and after the oral administration of glucose were significantly lower in the ISO-II group during the oral glucose tolerance test. The ISO-II group showed a tendency to elongate the gastrointestinal transit time. The activity of serum aminotransferases, indicator of liver function, was not negatively affected by any intake level of isoflavone. The present study demonstrated that the soybean isoflavone extract may be beneficial to diabetic animals by improving their glucose tolerance and suppressing weight loss without incurring hepatotoxicity at the daily dosage of 3.0 mg per kg of body weight.

Keyword

Soybean isoflavone extract; streptozotocin; diabetic rat; glucose tolerance; survival rate

MeSH Terms

Administration, Oral
Animals
Blood Glucose
Body Weight
Body Weight Changes
Diet
Fasting
Gastrointestinal Transit
Glucose Tolerance Test
Glucose*
Liver
Rats*
Soybeans*
Streptozocin
Survival Rate*
Transaminases
Weight Loss
Blood Glucose
Glucose
Streptozocin
Transaminases

Figure

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  Fig. 1 Blood glucose curves during OGTT in normal and diabetic rats. At week 7 of the experimental period, the rats were administered with a glucose solution (0.1 g/100g B.W.) and the plasma glucose was determined at 0, 30, 60, 120, 180min after glucose load. Abbreviations: ISO: soybean isoflavone extract. Different capital letters at the same time point indicate significant differences (p<0.05) among the five groups and different small letters at the same time point indicate significant differences (p<0.05) among the four diabetic groups by Duncan's multiple comparison test.

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