Antidiabetic, Hypolipidemic, and Antioxidant Activities of<i>Callistemon lanceolatus</i>Leaves Extract

Abstract

The present study was designed to investigate the antidiabetic, hypolipidemic, and antioxidant effects methanolic leaves extracts of Callistemon lanceolatus (CLE) in streptozotocin-induced diabetic wistar rats by administering graded oral doses (250 and 500 mg/kg body weight) for 21 days. Single oral administration of the extract reduced blood glucose level in both glucose-loaded and streptozotocin-induced diabetic rats. Daily oral treatment with CLE for 3 weeks resulted in reduced blood glucose, serum cholesterol, and triglycerides and improved HDL-cholesterol and serum insulin levels compared to the diabetic control group. The antioxidant activities of extracts were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging activity, superoxide anion, nitric oxide, and hydroxyl anion radical scavenging assays. The antioxidant activities were compared to standard antioxidants such as butylated hydroxyl anisole and ascorbic acid. All the extracts showed antioxidant activity in all the tested methods.