Hypoglycemic and Anti-hyperlipidaemia Effects of Methanolic Extract of Zingiber officinale and its Role in Ameliorating Oxidative Stress in Alloxan-induced Diabetic Rats

This study was designed to examine the hypoglycemic and antioxidant defense by methanolic extract of Zingiber officinale on alloxan induced diabetes in Wistar rats.The preliminary study showed that Z. officinale extract was able to scavenge the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2,-azinobis (3-ethylbenzoline-6-sulphonic acid (ABTS) radicals and these radicals scavenging abilities were found to be dose-dependent. Alloxan induced diabetes mellitus in rats was accompanied by increases in serum glucose and activities of alkaline phosphatase (ALP), alanine transferase (ALT) and aspartate transferase (AST). Diabetic rats also exhibited lower activities of superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH) content and higher level of malondialdehyde (MDA) in hepatic and renal tissues as compared with normal rats. However, supplementation of diabetic rats with Z. officinale extract at the doses of 50 mg/kg and 100 mg/kg body weight for 7 days caused reversal of all these effects significantly, it also resulted in dose-dependent hypoglycaemic status and improved the lipid profile of the treated groups indicating that the high levels of triglyceride and total cholesterol associated with diabetes can also be significantly managed with the extract. These findings suggest that Z. officinale treatment exerts a therapeutic protective effect in diabetes by decreasing oxidative stress, and hepatic and renal damage. Z. officinale was found to contain high level of total phenolic content (52.42 mg/g in GAE/g dried weight) which maybe speculated to account for the observed pharmacological effects of the plant.