Effects of an ethanolic extract of Garcinia kola on glucose and lipid levels in streptozotocin induced diabetic rats

Abstract

The effect of Garcinia kola on glucose and lipid levels in streptozotocin-induced diabetic rats was investigated. Ethanolic extract of G. kola was prepared and used for animal treatments. Diabetes was induced by a single intraperitoneal injection of streptozotocin (40 mg/kg body weight). Acute effects of G. kola on glucose were investigated by giving a single dose of distilled water or 300 mg/kg G. kola extract or metformin 300 mg/kg. Glucose levels were measured 2, 4 and 6 h after treatment. To investigate the long term effects, animals were treated daily for four weeks with either distilled water (controls) or 300 mg/kg G. kola extract. At termination, serum glucose, low density lipoprotein (LDL) and high density lipoprotein (HDL) levels were measured. There was no significant difference (P>0.05) in single dose glucose levels, long term HDL levels and body weights compared to the controls. However, in the four week treated rats, glucose (mmol/L) was significantly lower (16.2±2.9; P<0.05) than in the controls (21.6±3.6) and the LDL levels were significantly decreased by 66% in the treated group compared to controls (P<0.01; 86.8±18.2 versus 29.8±10.9). This confirms the hypoglycaemic and especially the hypolipidemic effects of G. kola in a diabetic rat model.

Keywords: G. kola, ethanolic extract, hyperglycemia, low density lipoprotein (LDL), high density lipoprotein (HDL), streptozotocin