Gentamicin-induced nephrotoxicity is associated with free radicals generation in kidney tissue. Medicinal plants contain bioactive constituents that act as natural antioxidants, which can protect the biological system from oxidative stress. In this study, phytochemical constituents of aqueous extract of Calotropis procera flowers and its efficacy on gentamicin-induced nephrotoxicity in rabbit model were evaluated. Renal function markers, total oxidant status and catalase activity were assessed along with hematological and renal histopathological analyses. Phytochemical analysis showed the presence of tannins, flavonoids, saponins, glycosides, phenols, alkaloids, steroids and ascorbic acid. Gentamicin administration led to severe changes in serum biochemical markers along with significant alteration in kidney tissue. Co-administration of plant extract with gentamicin reduced the gentamicin-induced toxic effects by restoring the renal function markers i.e. blood urea nitrogen, serum urea, serum creatinine and electrolytes indicating the protective potential of plant extract. Likewise, disturbance in hematological parameters induced by gentamicin was attenuated by the administration of plant extract. In addition, C. procera extract increased the antioxidant enzyme catalase and decreased the serum total oxidant status along with protective effects evidenced by histopathological evaluation. Aqueous extract of C. procera flowers, when co-administered with gentamicin, exerted protective effect against gentamicin-induced nephrotoxicity in rabbits. This nephroprotective potential of C. procera aqueous extract might be due to the presence of polyphenols i.e. flavonoid and phenol constituents.

Key words: Antioxidant enzymes, Medicinal plants, Nephrotoxicity, Phytochemistry