Hibiscus Sabdariffa Reduces Renal Damage in Experimental Streptozotocin-Induced Diabetes

This study evaluated the nephroprotective and antioxidant potential of methanolic extract of Hibiscus sabdariffa L. calyx (HSCE) on normal and streptozotocin-induced diabetic Wistar rats. Type 1 diabetes mellitus was induced in Wistar rats by a single intraperitoneal injection of 80 mg/kg b.w. Streptozotocin (STZ) dissolved in 0.1 M citrate buffer (pH 6.3). The rats were divided into five groups (n =12) including normal control group, test group I, diabetic negative control, test group II, and diabetic positive control. The test groups received 1.75 g/kg bw of HSCE by gavage for 15 days. Animals were sacrificed; their kidney tissues and serum were evaluated for histopathological and biochemical parameters. The protective effects of the extract on STZ-diabetes induced renal damage was evident from the results of the histopathological analysis and the biochemical parameters evaluated in the serum and kidney homogenates. Reduced levels of glutathione, catalase and superoxide dismutase in the kidney of diabetic rats were significantly improved in the H. sabdariffa -treated rats (p < 0.05). Elevated concentrations of urea and creatinin in the serum of diabetic rats were also significantly lowered (p < 0.05) in HSCE-treated rats. Examination of stained kidney sections revealed hydropic glomerular and tubular degenerations, Bowman space diminution, glomerular and tubular basement membrane thickening as well as excessive deposition of glycogen and collagen in the renal interstitium. The kidneys of HSCE-treated rats were protected from these pathological changes. The protective effects of the extract on STZ-diabetes-induced renal damage could be partly related to its antioxidant activity.

Key Words: Streptozotocin diabetic nephropathy; Hibiscus sabdariffa; Antioxidant; Anthocyanin; Protocatechuic