Oral administration of Eucalyptus globulus extract reduces the alloxan-induced oxidative stress in rats

In light of evidence that some complications of diabetes mellitus may be caused or exacerbated by an oxidative stress, the putative protective effect of Eucalyptus globulus, a medicinal plant, was investigated in alloxan-diabetic rats. E. globulus extract was given in drinking water for 15 days at a daily dose equivalent to 130 mg dry leaves/kg of body weight. Lipids peroxidation level and activities of catalase, superoxide-dismutase and glutathione peroxidase were then measured in liver and kidney. Under our experimental conditions, eucalyptus extract was found to significantly reduce the blood glucose level in diabetic animals but failed to restore the liver glycogen level, whereas insulin lowered blood glucose and restored liver glycogen to high concentration. Our results suggest that the antihyperglycemic action of eucalyptus extract is not exerted via the stimulation of insulin secretion but rather unveil a proper effect of the extract involving the enhancement of peripheral glucose uptake. In addition, eucalyptus extract appears to exert an antioxidative activity demonstrated (1) by the increase of catalase, superoxide-dismutase and gluthatione-peroxidase activities in liver and kidney, and (2) a lowering of lipids peroxidation level in these organs. In conclusion, the present study indicates that extract of E. globulus, administered per os, could be used with some profit in diabetic patients.