Modulation of Antioxidant Enzymes and Inflammatory Cytokines: Possible Mechanism of Anti-diabetic Effect of Ginger Extracts

Zingiber officinale is used in African traditional medicine to treat diabetes mellitus. Oxidative stress and inflammation are associated with the pathogenesis of diabetes mellitus and its complications. This investigation tested the hypothesis that extracts of Zingiber officinale inhibit oxidative stress and inflammation by enhancing antioxidant enzymes and TNF-α activity in STZ-induced diabetic rats. Wistar rats were randomly divided into groups (n=6) receiving different oral treatments consisting of vehicle, aqueous ginger extract (250 and 500 mg/kg), ethanol ginger extract (250 and 500 mg). The effect of Z. officinale was assessed in the STZ-induced diabetic rats after 6-week treatment on blood glucose; oxidative stress (using MDA level, SOD, CAT and GSH activities); and inflammation (using TNF-α). Both extracts of Z. officinale increased the intracellular activities of SOD, CAT and GSH. The extracts however caused a significant decrease in the MDA and inflammatory TNF-α level. These data indicate that mechanism of antidiabetic effects of ginger may be in part, due to inhibition of oxidative stress and inflammatory activity.