Protective effect of gallic acid isolated from Peltiphyllum peltatum against sodium fluoride-induced oxidative stress in rat's kidney

In the present study, the nephroprotective effect of gallic acid isolated from Peltiphyllum peltatum was examined in sodium fluoride (NaF) treated rats. Nephrotoxicity was induced by 1-week intoxication of NaF at 600 ppm through drinking water. The levels of thiobarbituric acid reactive substances, reduced glutathione as well as activities of superoxide dismutase and catalase in renal tissues homogenates were determined. The serum biochemical markers of renal injuries including creatinine, serum urea, blood urea nitrogen, uric acid levels as well as the levels of phosphate and calcium were also assessed. Intoxication with NaF caused a significant increase in the levels of thiobarbituric acid reactive substances (46 % versus to control) and reduced the glutathione concentration (47 %) and the activities of superoxide dismutase (46 %) and catalase (41 %) in renal tissues homogenates. NaF intoxication also induced significant alterations in the kidney biochemical markers increasing the levels of urea, uric acid, blood urea nitrogen, creatinine, and phosphate and decreasing the levels of calcium. Daily administration of gallic acid (20 mg/kg) for 1 week before NaF intoxication brought the antioxidant-oxidant balance similar to the NaF-untreated group. Silymarin, used a standard antioxidant agent, also showed a nephroprotective activity. We concluded that NaF caused nephrotoxicity and oxidative stress in renal tissues and daily administration of gallic acid for 1 week prior to intoxication inhibited toxicity and oxidative stress.