Garlic and Kidney Injury Protection

Recently much attention has been directed towardattenuation of renal tubular cell injury by herbal antioxidants(1-3). medicinal plants are plentiful sources ofpolyphenols with antioxidant activities and these beneficialproperties have been attributed to their antioxidantmechanisms (4-6). there has also been a linear associationbetween oxygen radical absorbance capacity valuesand total phenolic contents in several herbal medicines(7-12). garlic (allium sativum l) is an important part in thecomplementary and alternative medicine (13, 14). to investigatethe ameliorative effect of garlic extract on renalbiochemical and histologic alterations of gentamicin-inducedkidney damage in rats, we conducted a preclinicalinvestigation (15). in this study, we found attenuation ofgentamicin-induced acute kidney injury by garlic juice inmale rats. in this study, fifty male rats were divided into5 groups of 10 as follows: group 1, sham group (control);group 2 (positive control group), gentamicin (gm) for10 days; group 3, garlic and gm for 10 days; group 4, gmfor 10 days followed by garlic juice for 10 days; and group5, gm for 10 days followed by saline solution for 10 days.gm, 10 mg/kg, and garlic extract, 20 mg/kg, were administeredintraperitoneally. in our study, we found serum creatininewere significantly high in the gentamicin group(group 2) after the experiment. however, the level of creatininein group 3 (co-treatment with gentamicin andgarlic) were significantly lower than those in group 2. serumcreatinine also lower in group 4 (consecutive treatmentwith gentamicin and garlic), when compared withgroup 5 (gentamicin and saline). we also assessed the pathologydamage score. histopathological study, showedthe higher injury for gm group. post-administration ofgarlic after gm treatment (group 4) or co-administrationof garlic and gm (group 3) significantly attenuated thedamage score. in this study, we concluded that, garlic extract,has regenerative potential after tubular injury inducedby gm in animal models (15). additionally, to findthe efficiency of co administration of garlic extract andmetformin for prevention of gentamicin–kidney tubularcell injury, we conducted another investigation on 70male rats (16). the results of this study showed that metforminand garlic juice or their combination has bothcurative and protective effect against gentamicin renaltoxicity (16).the protective effect of the garlic derived antioxidants-allylcysteine on kidney injury and oxidativestress induced by ischemia and reperfusion was shownpreviously (15, 16). it was found, that garlic have high levelof antioxidant activity. the s-allylmercaptocysteine as oneof the water soluble organo-sulfur compounds of garlicjuice scavenges hydroxyl radical and abolishes oxidativeand nitrosative stress. interestingly, it was found that, theequivalent antioxidant capacity values of several forms ofgarlic extracts were associated well with their total phenolic,flavonoid and flavonol contents (1). diabetic kidneydisease is one of the most important complications ofdiabetes mellitus (17-21), and metformin has been mostlyused for treatment of this disease (13, 14, 22-25). thusit is possible that garlic extract protects against tubularinjury induced by diabetes and restoring the biochemicalalterations and modulation of oxidative stress on thetubules (3, 24). furthermore, in diabetic kidney disease,there is also tubular cell injury due to glycosuria (26-28).these findings can more potentiate the clinical use ofcombination of metformin and garlic extract in diabeticpatients to protect better the kidneys. in our studies, weshowed co-administration or post-administration of garlicfor gm-induced acute renal injury was applicable (23,25-31). thus, we conclude that garlic is a kidney protectivedrug to improve tubular injury by gm or other nephrotoxicdrugs which act like the same mechanisms as theaminoglycoside does. however in this regard, to betterunderstand the garlic renal protective properties, moreanimal and clinical studies are suggested.acknowledgementsthere is no acknowledgment.