Evaluation of antidiabetic activity of the seeds ofSwietenia macrophyllain diabetic rats

The effect of a methanol extract of the seeds of Swietenia macrophylla King. (Meliaceae) was evaluated with streptozotocin-induced diabetic rats. Forty-eight hours after streptozotocin injection, the extract, at doses of 200 and 300 mg/kg, was administered orally for 12 consecutive days. Oral glucose tolerance test (OGTT) and normoglycemic activity were also measured during this course of experiment. The extract was found to be potent antidiabetic as evidenced by significant (p < 0.01) reduction of blood glucose level of diabetic rats from day 5 onward by both the doses (maximal effect of 59.69% reduction of blood glucose level, at 300 mg/kg, on day 12, p < 0.01). Results demonstrated a significant reduction of serum lipids (maximal effect of 45.41 and 37.78% reduction of cholesterol and triglyceride, respectively, at 300 mg/kg, p <0.01) and elevation of liver glycogen level (maximal effect of 58.14%, at 300 mg/kg, p < 0.01) in diabetic rats, comparable to that of standard antidiabetic glibenclamide at 10 mg/kg. In OGTT, the extract at different doses showed significant reduction in plasma glucose level (p < 0.01) at the second hour. The extract also revealed low reduction of fasting blood glucose level in normal rats (maximal effect of 19.64% reduction, at 300 mg/kg, on day 12, p < 0.01) while glibenclamide at 10 mg/kg exhibited maximum effect of 23.27% (p <0.01) on day 12. Improvement of body weight profile was also observed in extract-treated diabetic rats.