Protective effects of extract and fraction of root- bark of Garcinia kola (Heckel) on the renal biochemical parameters of gentamicin-induced nephrotoxic rats

The study evaluated the nephroprotective potentials of methanolic extract (ME) and dichloromethane fraction (DCMF) of root-bark of Garcinia kola on gentamicin-induced nephrotoxicity in rats with a view to utilize the extracts of the root of G. Kola in the amelioration of antibiotic-induced kidney damage. The study involved preparation of the extract, fractionation, phytochemical screening and evaluation of phenolics and flavonoid contents. Moreover, both the acute and sub-acute toxicities of ME and DCMF were determined in mice and albino rats with concentrations ranging from 10 to 5000 mg/kg body weight (bwt) respectively. Forty albino rats were divided into 8 groups of five animals each and induced with gentamicin (80 mg/kg bwt). The renal biochemical metabolites and enzymes were quantified and assayed respectively. The histopathological examinations of kidney were carried out. Phytochemical screening of the ME and DCMF of the root-bark of G. kola revealed the presence of flavonoids, tannins, cardiac glycosides, saponins, alkaloids and terpenoids. The extract and DCMF did not elicit any adverse effect and a dose of 250 mg/kg bwt of ME and DCMF was selected for further studies. The administration of gentamicin (80 mg/kg bwt) caused elevated levels of plasma renal biomarkers, reduction in AciPase activities. Moreover, administration of gentamicin (80 mg/kg bwt) resulted in damage to kidney structures. The treatments (pre and post) of the rats with 250 mg/kg extract and fraction reversed alterations of biochemical parameters which were supported by low levels of tubular and glomerular injuries induced by gentamicin treatment. The study concluded that, both the extract and fraction of G. kola root-bark elicited antioxidant and appreciable nephroprotective potentials. Key words: Antioxidant potentials, Garcinia kola, Methanolic extract, Nephrotoxicity, Renal biomarkers.