Protective effect of curcumin and gingko biloba l. extract against gentamicin-induced nephrotoxjcity in rats

Gentamicin [GENT] which is a commonly used antibiotic causes nephrotoxicity in man and animals. Generation of free radicals in the renal cortex plays an important role in the pathogenesis of gentamicin-induced nephrotoxicity in rats. Curcumin, the yellow curry pigment isolated from turmeric [the ground rhizome of Curcuma longa L] and Ginkgo biloba extract have been reported to possess antioxidant and free radical scavenging properties. The present study was designed to investigate the potential protective role of curcumin, Ginkgo biloba extract, and their combination on gentamicin-induced nephrotoxicity in rats. The rats were divided into six groups, 8 animals each. Group 1 rats were treated with GENT [80 mg/kg/day] IM for 6 days. Rats of groups 2, 3, and 4 "were pretreated orally for 4 days with curcumin [200 mg/kg/day], Ginkgo biloba leaf extract [300 mg/kg/day], and a combination of curcumin and Ginkgo biloba leaf extract, respectively before concomitant administration of GENT for additional 6 days. Control groups of animals were treated with pure vehicles IM or orally. Nephrotoxicity was evaluated biochemically and histopathologically. Treatment of rats with GENT produced elevation in serum creatinine, urea levels and severe tubular necrosis. Concomitantly, treatment of rats with GENT produced elevation in serum nitrite level, decrease in renal intracellular reduced glutathione [GSH] level and superoxide dismutase [SOD] activity. Pretreatment of rats with curcumin, Ginkgo biloba extract, or their combination decreased GENT-induced disturbances in kidney function and structure. In addition, pretreatment of rats with curcumin, Ginkgo biloba extract, or their combination decreased GENT-induced alterations in serum nitrite level, renal intracellular GSH level and SOD activity. The combined treatment was more effective than either agent alone. These results indicate that curcumin, Ginkgo biloba extract, or their combination has the ability to protect against GENT-induced nephrotoxicity. Inhibition of oxidative stress and nitric oxide production may play an important role in these protective effects