Antidiabetic effect of nitobegiku in KK-Ay diabetic mice.

In the past, nitobegiku (the herb of Tithonia diversifolia (Hemsl) A. Gray) has been used as a medicinal plant for diabetes. Antidiabetic effect of the water extract of Nitobegiku (NG) was investigated in KK-Ay-mice--one of the animal models of type 2 diabetes. NG (1,500 mg/kg body weight) reduced the blood glucose of KK-Ay mice from 509 +/- 22 mg/dl to 340 +/- 14 mg/dl (p < 0.001) and also lowered the plasma insulin (p < 0.05) 7 hours after single oral administration. No change in blood glucose of NG-treated normal mice (ddY) was seen. These results support that NG improve glucose metabolism by reducing insulin resistance. Therefore, NG may be useful for treatment of type 2 diabetes.