Dose-dependent effect of galangin on fructose-mediated insulin resistance and oxidative events in rat kidney.

Galangin is an antioxidant flavonol present in high concentrations in the rhizome of Alpinia galanga. We investigated the effect of galangin on whole-body insulin resistance and kidney oxidative stress in a fructose-induced rat model of metabolic syndrome. Male albino Wistar rats were divided into 6 groups containing six animals each. Groups I and VI received a starch-based control diet, while groups II, III, IV and V were fed a high fructose diet (60 g/100 g). Groups III, IV and V additionally received galangin (50, 100 and 200 μg/kg body weight, respectively) while group VI received 200 μg galangin/kg body weight. At the end of 60 days, fructose-fed rats exhibited insulin resistance, increased levels of peroxidation end products and diminished antioxidant status. galangin, dose-dependently normalized blood glucose and insulin levels. The minimum effective dose was 100 μg galangin/kg body weight. At this dose, galangin also prevented the development of insulin resistance and the exaggerated the response to oral glucose challenge. The oxidant-antioxidant balance was maintained by galangin. Micro-albuminuria and tubular and glomerular changes observed in fructose-treated rats were significantly prevented by galangin (100 μg/kg body weight). These findings imply that galangin potentiates insulin sensitivity and antioxidant capacity and reduces renal damage in this dietary model of metabolic syndrome.