Effect of garlic (Allium sativum) on nickel II or chromium VI induced alterations of glucose homeostasis and hepatic antioxidant status under sub-chronic exposure conditions.

Garlic (Allium sativum) has a profound effect in reducing plasma glucose and increasing serum insulin in diabetic rats. We studied the effect of a garlic extract on nickel- or chromium-induced alteration of plasma glucose and hepatic glycogen levels and anti-oxidant status in rats. Adult male albino rats (n=36) divided into six groups of six animals each were treated as follows: Group I, untreated controls; Group II, fresh aqueous homogenate of garlic; Group III, nickel sulfate; Group IV, nickel sulfate + garlic; Group V, potassium dichromate; Group VI, potassium dichromate + garlic. In Groups IV and VI, the simultaneous administration of garlic abrogated a significant nickel- or chromium-induced increase in plasma glucose and decrease in liver glycogen. Nickel and chromium alone also increased lipid peroxide (LPO) and decreased glutathione levels, as well as the activity of superoxide dismutase (SOD), catalase, and glutathione peroxidase. Simultaneous garlic administration significantly reduced the LPO level and remarkably improved SOD activity. Hence, we postulate that the administration of garlic can prevent nickel II- or chromium VI-induced alterations in blood glucose homeostasis while exerting a hepatoprotective effect on glycogen levels and antioxidant status in male albino rats.