Modulatory effects of rooibos and red palm oil on antioxidant status in streptozotocin-induced hyperglycemic male Wistar rats

Abstract

Rationale: Oxidative stress, mediated chiefly by hyperglycemia-induced generation of free radicals has been reported to contribute to the progression of diabetes and its complications. Methods: Male Wistar rats (192 240 g) were bred and used for the study. Proper procedures for handling animals were followedad and the animals were randomly placed in eight groups with seven (7) rats in non-diabetic groups and eight (8) rats in diabetic groups. Diabetes was induced by a single intramuscular injection of Streptozotocin (STZ) at the dose of 50 mg/kg of body weight. Only animals with fasting blood sugar levels above 14 mmol/L were considered for the experiment. Antioxidant enzymes, antioxidant capacity such as FRAP, ORAC, TEAC, GSHt, conjugated diene and TBARS were determined using appropriate standard methods. Results: Treatment of diabetic rats with RPO and RPO+ RTE improved the activities of GPx in the red blood cells and liver. The activity of liver SOD in the diabetic rats was significantly (P < 0.05) increased with RPO, RTE and RPO+RTE supplementation. Similarly, RPO, RTE and RPO+RTE significantly (P < 0.05) increased plasma FRAP and ORAC values in the diabetic rats.