Biochemical study on the hypoglycemic effects of onion and garlic in alloxan-induced diabetic rats

The present study was carried out to investigate the effects of onion (Allium cepa Linn) and garlic (Allium sativum Linn) juices on biochemical parameters, enzyme activities and lipid peroxidation in alloxan-induced diabetic rats. Alloxan was administered as a single dose (120mg/kgBW) to induce diabetes. A dose of 1 ml of either onion or garlic juices/100g body weight (equivalent to 0.4g/100gBW) was orally administered daily to alloxan-diabetic rats for four weeks. The levels of glucose, urea, creatinine and bilirubin were significantly (p < 0.05) increased in plasma of alloxan-diabetic rats compared to the control group. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), and alkaline and acid phosphatases (AlP, AcP) activities were significantly (p < 0.05) increased in plasma and testes of alloxan-diabetic rats, while these activities were decreased in liver compared with the control group. Brain LDH was significantly (p < 0.05) increased. The concentration of thiobarbituric acid reactive substances and the activity of glutathione S-transferase in plasma, liver, testes, brain, and kidney were increased in alloxandiabetic rats. Treatment of the diabetic rats with repeated doses of either garlic or onion juices could restore the changes of the above parameters to their normal levels. The present results showed that garlic and onion juices exerted antioxidant and anti hyperglycemic effects and consequently may alleviate liver and renal damage caused by alloxan-induced diabetes. (C) 2004 Elsevier Ltd. All rights reserved.