Antidiabetic Activity of Green Tea (Thea sinensis L.) in Genetically Type 2 Diabetic Mice

Abstract

The antidiabetic activity of Thea sinensis was investigated in KK-Ay mice, an animal model of genetically type 2 diabetes with hyperinsulinemia. The water extract of Thea sinensis (green tea cold ext) (100 mg/kg body weight) reduced the blood glucose of KK-Ay mice 4 and 8 weeks after repeated administration and tended to decrease the plasma insulin level of KK-Ay mice under similar conditions. However, green tea cold ext did not affect blood glucose levels in normal mice. Green tea cold ext decreased blood glucose levels in an insulin tolerance test. These results suggest that the antidiabetic activity of green tea cold ext is derived, at least in part, from a decrease in plasma insulin, due to decreased insulin resistance.