Preadministration of Fermented Sorghum Diet Provides Protection against Hyperglycemia-Induced Oxidative Stress and Suppressed Glucose Utilization in Alloxan-Induced Diabetic Rats

Abstract

Sorghum bicolor grains are rich in phytochemicals known to considerably impact human health. Several health-promoting products such as flour, staple food, and beverages have been produced from sorghum grains. This study investigated the protective and modulatory effects of a sorghum diet on the genes of some antioxidant and glycolytic enzymes in alloxan-induced diabetic rats. The rats were randomly distributed into six groups: the control group received normal diet, while the other groups were pretreated with 12.5, 25, 50, 75, and 100% of the sorghum diets daily for 8 weeks before the administration of a dose of alloxan (100 mg/kg BW), after which blood was collected and the liver was excised. The effects of the diets on blood glucose levels, liver dysfunction indices, and markers of oxidative stress were assessed spectrophotometrically, while the gene expressions of key glycolytic enzymes and enzymatic antioxidants were assayed using reverse transcriptase polymerase chain reaction. It was observed that the pretreatment of the experimental animals with the diets normalized the blood glucose before and after the administration of alloxan. The sorghum-treated groups also showed statistically significant (p < 0.05) decrease in liver dysfunction indices and markers of oxidative damage compared with the control. In addition, statistically the diets significantly decreased (p < 0.05) the relative expression of superoxide dismutase, glutathione peroxidase, glucokinase, phosphofructokinase, and hexokinase genes in the experimental animals compared with the control. Overall, this study showed that the preadministration of fermented sorghum diet significantly protected against hyperglycemia and suppressed glucose utilization via glycolysis in the liver of alloxan-induced diabetic rats. Thus, the consumption of sorghum diet may protect against hyperglycemia and oxidative damage and may therefore serve as functional food for management of diabetic mellitus.

Keywords: antioxidants; diabetes mellitus; gene expression; glycolytic enzymes; nutrition; oxidative stress; sorghum.

Figure 1

Effects of fermented sorghum diet on (A) the blood glucose levels before and after induction of diabetes, (B) the activities of alanine transaminase (ALT) in the erythrocyte, (C) the activities of ALT in the liver, (D) the activities of aspartate transaminase (AST) in the liver of alloxan-induced diabetic rats. All values are represented as the means ± SEM (n = 5). *Significant differences at p < 0.05 from the control group.

Figure 2

Effects of fermented sorghum diet on (A) MDA equivalents, (B) the activities of superoxide dismutase, and (C) the activities of peroxidase in the liver of alloxan-induced diabetic rats. All values are represented as the means ± SEM (n = 5). *Significant differences at p < 0.05 from the control group.

Figure 3

Effects of fermented sorghum diet on relative expression of hepatic (A) glutathione peroxidase, (B) superoxide dismutase, (C) glucokinase, (D) phosphofructokinase-1, and (E) hexokinase genes in alloxan-induced diabetic rats. All values are represented as the means ± SEM (n = 5). *Significant differences at p < 0.05 from the control group.