Methanolic extract of Cola nitida elicits dose-dependent diuretic, natriuretic and kaliuretic activities without causing electrolyte impairment, hepatotoxicity and nephrotoxicity in rats.

Cola nitida (Kolanut) is conventionally used in tropical Africa for the treatment of all kinds of ailments such as migraine, morning sickness, metabolic disorders etc. However, this study was designed to investigate the diuretic, natriuretic and kaliuretic activities of methanolic extract of Cola nitida (MECN) in male Wistar rats. Adult male Wistar rats were randomly allotted into control (25 ml/kg b.w.), furosemide (20 mg/kg b.w; standard), MECN1 (100 mg/kg), MECN2 (200 mg/kg), MECN3 (300 mg/kg), MECN4 (400 mg/kg), MECN5 (500 mg/kg), MECN6 (600 mg/kg) groups with n=6. The extract was prepared as previously described and the treatment lasted for 14 days. Urine volume and diuretic indices were estimated. Urine electrolytes, plasma electrolytes, plasma/renal AST/ALT, plasma creatinine and urea were assayed using flame photometry and standard colorimetric method respectively.Administration of different doses of C. nitida significantly altered body weight gain and water intake but not food intake compared with control group. There were significant increases in urine volume and urine electrolytes (Na+, K+ and Cl-), a decrease in plasma/renal ALT and AST activities, a decrease in plasma creatinine and urea concentration and no alteration in plasma electrolytes when compared with control and furosemide-treated groups. Our study suggests that MECN elicits diuretic, natriuretic, and kaliuretic activities without causing electrolyte impairment, hepatotoxicity and nephrotoxicity. These effects are dose-dependent.