Antihyperglycemic activity of the aqueous extract of Urtica dioica

When administered 30 min before glucose loading, the aqueous extract of Urtica dioica (nettle) (250 mg/kg) showed a strong glucose lowering effect. The decrease of glycemia has reached to 33+/-3.4% of the control value 1 h after glucose loading. This effect was persistent during 3 h. In contrast, nettle did not show hypoglycemic effect in alloxan-induced diabetic rats. The amount of glucose absorbed in a segment jejunum in situ was 8.05+/-0.68 mg in presence of nettle extract vs. 11.11+/-0.75 mg in control rats during 2 h (P<0.05). The results indicate that nettle has a significant antihyperglycemic effect in OGTT model. This effect may be caused in part by the reduction of intestinal glucose absorption. LD(50) is 3.5 g/kg (i.p.).