Indian Journal of Experimental Biology Vol. 49, July 2011, pp. 498-510 Protective effect of aqueous garlic extract against lead-induced hepatic injury in rats Debamita Kilikdar, Debasri Mukherjee, Elina Mitra, Arnab K Ghosh, Anjali Basu, Ananga Mohan Chandra & Debasish Bandyoapdhyay* Oxidative Stress and Free Radical Biology Laboratory, Department of Physiology, University of Calcutta, 92, APC Road, Kolkata 700 009, India Received 14 September 2010, revised 11 March 2011 Effect of aqueous extract of garlic on hepatic injury due to lead-induced oxidative stress in experimental rats has been investigated. Lead acetate (LA) at a dose of 15 mg / kg body wt was administered ip to rats for 7 consecutive days to induce hepatic injury. Freshly prepared aqueous garlic extract (AGE) at a dose of 50 mg /kg body wt was fed orally to rats 1 h before LA treatment for similar period. LA treatment caused hepatic injury as evident from increased activities of serum glutamate pyruvate transaminase (SGPT) and alkaline phosphatase (ALP), increased serum bilirubin level and damage in the tissue morphology. Lead-induced oxidative stress in liver was evident from increased levels of lipid peroxidation and reduced glutathione. The decreased activity of superoxide dismutase (SOD) and an increased activity of catalase as well as an increased activity of xanthine oxidase (XO) indicate generation and possible accumulation of reactive oxygen intermediates. Furthermore, altered activities of lactate dehydrogenase (LDH), isocitrate dehydrogenase (ICDH), alpha-keto glutarate dehydrogenase (-KGDH) and succinate dehydrogenase (SDH) also indicate an impaired substrate utilization and generation of oxidative stress. All these changes were found to be mitigated when the rats were pre-treated with the AGE. Results indicate that AGE has the potential to ameliorate lead-induced hepatic injury due to oxidative stress in rats. The protective effects may be due to the antioxidant properties of AGE and may have future therapeutic relevance. Keywords: Antioxidant, Garlic, Lead, Liver, Oxidative stress Human exposure to heavy metals has risen dramatically in the last 50 years as a result of an exponential increase in the use of heavy metals in industrial processes and products 1 . Many metals play important role in the functioning of enzymes, cell-signaling processes, and gene regulation 2 . Heavy metals, like lead is not known to have any biological role. Increasing concern has been expressed about the rapidly rising level of chemicals in the environment, particularly lead, which has well-known hazardous effects. It affects each and every organ and system in the body 1 . In India, the range of sources of lead exposure is extensive. This ubiquitous environmental pollutant enters the atmosphere from production of coal, oil, iron, steel, and batteries, as well as from smelters, solid waste, and tobacco smoke. Lead exposure occurs mainly though the respiratory and gastrointestinal systems. Liver is a frequent target for many toxicants. The currently approved treatment for lead intoxication is to give chelating agents, such as meso-2, 3-dimercaptosuccinic acid (DMSA) and monoisoamyl DMSA (MiADMSA), which form an insoluble complex with lead and shield it from biological targets, thereby reducing its toxicity. However, these chelators are potentially toxic and often fail to remove lead from all the body tissues 3 . Moreover, because of their hydrophilic nature, they cannot cross the cell membrane to capture intracellular lead 3 . Thus, drugs with lipophilic properties are needed. Use of natural antioxidants in the treatment and/or control of a number of stress-induced diseases are currently being favoured. The role of antioxidants in ameliorating oxidative damage brought about by the environmental or occupational exposure to heavy metals has been reported 4,5 . The human diet, which contains many natural compounds, is thought to have the capability to provide protection to the body against the development of many diseases. Garlic (Allium sativum L.), which comprises an important component of the regular diet of the people in South East Asia including India and China, has been shown —————— *Correspondent author Telephone: +91-033-2350 8386/ 6387/ 6397/ Extn 224 Fax: +91-033-2351 9755 E-mail: debasish63@gmail.com