Nutr Res Pract.  2007 Sep;1(3):184-188.

Inhibitory activity of Euonymus alatus against alpha-glucosidase in vitro and in vivo

• Lee SK
• Hwang JY
• Song JH
• Jo JR
• Kim MJ
• Kim ME
• Kim JI

Abstract

The major goal in the treatment of diabetes mellitus is to achieve near-normal glycemic control. To optimize both fasting blood glucose and postprandial glucose levels is important in keeping blood glucose levels as close to normal as possible. alpha-Glucosidase is the enzyme that digests dietary carbohydrate, and inhibition of this enzyme could suppress postprandial hyperglycemia. The purpose of this study was to test the inhibitory activity of methanol extract of Euonymus alatus on alpha-glucosidase in vitro and in vivo to evaluate its possible use as an anti-diabetic agent. Yeast alpha-glucosidase inhibitory activities of methanol extract of E. alatus were measured at concentrations of 0.50, 0.25, 0.10, and 0.05 mg/ml. The ability of E. alatus to lower postprandial glucose was studied in streptozotocin-induced diabetic rats. A starch solution (1 g/kg) with and without E. alatus extract (500 mg/kg) was administered to diabetic rats by gastric intubation after an overnight fast. Plasma glucose levels were measured at 30, 60, 90, 120, 180, and 240 min. Plasma glucose levels were expressed in increments from baseline, and incremental areas under the response curve were calculated. Extract of E. alatus,which had an IC50 value of 0.272 mg/ml, inhibited yeast alpha-glucosidase activity in a concentration-dependent manner. A single oral dose of E. alatus extract significantly inhibited increases in blood glucose levels at 60 and 90 min (p<0.05) and significantly decreased incremental response areas under the glycemic response curve (p<0.05). These results suggest that E. alatus has an antihyperglycemic effect by inhibiting alpha-glucosidase activity in this animal model of diabetes mellitus.

Keyword

Euonymus alatus; alpha-glucosidase; postprandial glucose; diabetes mellitus

MeSH Terms

alpha-Glucosidases*
Animals
Blood Glucose
Diabetes Mellitus
Dietary Carbohydrates
Euonymus*
Fasting
Glucose
Hyperglycemia
Inhibitory Concentration 50
Intubation
Methanol
Models, Animal
Rats
Starch
Yeasts
Blood Glucose
Dietary Carbohydrates
Glucose
Methanol
Starch
alpha-Glucosidases

Figure

• 

  Fig. 1 Dose-dependent inhibition of yeast α-glucosidase activity of Euonymus alatus and acarbose. The inhibitory activities of the methanol extract of Euonymus alatus or acarbose were measured at concentrations of 0.5, 0.25, 0.1, and 0.05 mg/ml. □, Euonymus alatus extract; ♦, acarbose. Values represent means of triplicate measurements.

• 

  Fig. 2 Postprandial glucose response to Euonymus alatus extract in STZ-induced diabetic rats. In the control group (□), starch (1 g/kg) was administered orally to rats after an overnight fast. In the Euonymus alatus group (♦), starch (1 g/kg) plus Euonymus alatus methanol extract (500 mg/kg) was administered orally to rats after an overnight fast. Values represent mean ± SE (n = 8). *Significantly different at p<0.05.

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