Effects Of Fresh Allium Sativa Extract On Lipid Peroxidation, Glutathione Depletion, And Oxidative Stress Induced By Acetaminophen In Mice

摘要

Oxidative stress and lipid peroxidation reactions are some of the mechanisms through which many diseases produce their effects. Allium sativa (garlic) is widely used as spice or eaten raw in many cultures, and has it been reported to exert several health benefits. This study was designed to evaluate the antioxidant and anti-lipid peroxidative effects of fresh extract of Ugandan cultivars of garlic in acetaminophen induced toxicity in mice. The local Ugandan varieties of the garlic were obtained from a local market in Ishaka Town in Western Uganda, ground to paste and extracted at room temperature with 80 % ethyl alcohol. Graded doses of the extract were administered intraperitonially (i.p.) to Swiss mice for 5 days before a single i.p. dose of 250 mg/kg acetaminophen. Levels of thiobarbituric acid reactive substances (TBARS) and glutathione (GSH) concentrations, and superoxide dismutase (SOD) and catalase (CAT) activities in liver homogenates were determined and compared to controls. Results showed that fresh extract of the local garlic prevented lipid peroxidation, preserved liver GSH stores, and up regulated SOD and CAT activities in the liver in a dose dependent manner. These results suggest that regular consumption of local Ugandan garlic could protect the body from oxidative stress and lipid peroxidation reactions induced by several diseases. Introduction Oxidative stress and lipid peroxidation play central roles in the pathogenesis and progression of several disorders. Cancer, ageing, atherosclerosis, and inflammatory processes have all been linked to the generation of reactive oxygen species and toxic metabolites of lipid peroxidation reactions. 1, 2, 3 In many models, depletion of liver glutathione stores and other antioxidant molecules constitute an important mechanism for the induction of oxidative stress and the concomitant damage to biological molecules such as proteins and nucleic acids, and the activation of nuclear transcription factors that may be important in the generation of pro-inflammatory cytokines 4, 5, 6, 7, 8. Several anti-oxidants have been used in the treatment of oxidative stress-mediated diseases, including vitamins (C and E), carotenoids, and minerals such as selenium. 9, 10, 11,12 Also, ethnomedical practices have relied on the use of plant products which are now known to contain antioxidant secondary metabolites.13 Garlic and garlic products have been employed in medical practice since antiquity. Various pharmacological studies have also reported on the benefits of its extracts and products on vital physiological functions including their antioxidant, 14 cardioprotective, 15 hepatoprotective, 16 anticancer 17 and anti-inflammatory effects. 18 However, most of these studies focused on the use of aged garlic extract (AGE) or other commercial products. Here we report on the anti-oxidant and anti-lipid peroxidative properties of fresh ethanolic extract of local Ugandan cultivars of garlic in mice models of acetaminophen induced lipid peroxidation and oxidative stress. We hypothesize that regular consumption of fresh garlic could prevent oxidative stress and protect against diseases associated with oxidative stress and lipid peroxidation reactions. Materials And Methods Collection, Identification, and Processing of Garlic BulbsBulbs of a local variety of garlic (Allium sativum L.) were obtained from Ishaka Town in Western Uganda, and identified by a qualified taxonomist. Cold extraction of the garlic was carried out at room temperature (18-22 o C) as follows: Fresh garlic bulbs were ground to a fine paste using a mechanical grinder and 50 g of the paste was put in a 250 ml conical flask and covered with 100 ml of 80 % ethanol, stoppered with cotton wool, and allowed to stand in the dark at room temperature for 48 hours. The ethanolic extract was filtered off with a Whatman no. paper into pre-weighed evaporating dishes, while the residue in the flask was washed with a further 100 ml of 80 % ethanol an