Antidiabetic activity evaluation of glimepiride and Nerium oleander extract on insulin, glucose levels and some liver enzymes activities in experimental diabetic rat model.

The present study is aimed to assess the therapeutic potential of sulfonylurea drug glimepiride in comparison with Nerium oleander plant extract on insulin, glucose levels and some liver enzymes activities in streptozotocin-induced diabetic rats. Rats were rendered diabetic by intraperitoneal injection of a single dose of 50 mg kg(-1) body weight streptozotocin. Rats with serum glucose levels > 200 mg dL(-1) were subdivided into three sub-groups: the first sub-group were remained without treatment and considered as diabetics. The second and third subgroups were orally administered 0.1 mg kg(-1) body weight/day glimepiride and 250 mg kg(-1) body weight/day Nerium oleander, respectively for 4 weeks. Streptozotocin-induced diabetic rats showed hypoinsulinemia and hyperglycemia compared to controls. Strong negative correlation (r = -0.8) was found between serum insulin and glucose levels in diabetic rats. This correlation was +0.4 and -0.3 in glimepiride and Nerium olender-treated rats, respectively implying that glimepiride and plant extract improved insulin and glucose levels with the former was more efficient. The activities of serum aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase were significantly increased in streptozotocin-induced diabetic rats compared to controls. Treatment of diabetic rats with glimepiride or Nerium oleander extract also improved liver enzymes activities.