Baicalin upregulates the genetic expression of antioxidant enzymes in Type-2 diabetic Goto-Kakizaki rats

Abstract

Aim: The primary purpose of this study was to characterize and investigate the antioxidant and anti-diabetic activities of the flavonoid baicalin in type 2 diabetic Goto-Kakizaki rats. Main methods: Four groups of Goto-Kakizaki rats (n = 6) were subjected to the following oral treatments for 30 days: (1) metformin - 500 mg/kg (2) baicalin - 120 mg/kg (3) metformin 500 mg/kg and baicalin - 120 mg/kg (4) vehicle treated diabetic controls receiving distilled water. The plasma glucose, triglyceride, total cholesterol, lipid peroxide and protein carbonyl contents were measured on a weekly basis. Following the completion of the treatment, the rats were sacrificed and their blood, heart, pancreatic and hepatic tissues were collected for analysis. The antioxidant enzyme activities as well as their expression were quantified using Western Blot, microarray and RT-PCR. Key findings: The respective analyses showed that the baicalin- and the metformin and baicalin-treated groups had statistically significant increases (p < 0.05) in the activity and expression of the antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) compared with vehicle- and metformin-treated groups. Further complementing the antioxidant enzyme activity increases, the oxidative stress markers of plasma lipid peroxide and protein carbonyl contents were reduced in these groups as well. These treatment groups also had reduced plasma total cholesterol and triglyceride levels compared with vehicle-treated and metformin-treated groups (p < 0.05). Significance: Baicalin was an efficient antioxidant in reducing hyperglycemia-induced oxidative stress through the increased expression of antioxidant enzyme activities. It was also an efficient anti- hypertriglyceridemic as well as anti-hypercholesterolemic agent compared with metformin. © 2011 Elsevier Inc. All rights reserved.