Effect of bitter melon (Momordica Charantia) on anti-diabetic activity in C57BL/6J db/db mice

Many herbal extracts have been reported to have a preventive or therapeutic effect of on diabetes mellitus. Momordica Charantia commonly known as bitter melon or karela has been reported to be a medicinal plant for treating various diseases including cancers and diabetes. The objectives of this study were to investigate anti-diabetic effects of bitter melon (BM) as determined by blood glucose levels, glucose tolerance test (GTT), insulin tolerance test (ITT), insulin and HbA∧1c activities in serum, serum biochemical and lipid levels histopathology, immunohistochemistry and AMPK-α2 expression of skeletal muscle in male C57BL/6J db/db mice. There were four experimental groups including vehicle control, BM 10 mg/kg, BM 50 mg/kg, and BM 250 mg/kg. BM at doses of 10, 50, and 250 mg/kg was orally administered to the diabetic mice everyday for 8 weeks. The treatments of BM 10, 50, and 250 mg/kg significantly decreased the blood glucose level in the diabetic mice compared with vehicle control (p less than 0.05). The treatments of BM 10 and 50 mg/kg significantly decreased the GTT, ITT and HbA1c levels in the diabetic mice compared with vehicle control (p less than 0.05). All BM groups significantly decreased GOT, GPT, BUN, LDL and glucose levels in the diabetic mice compared with the vehicle control mice (p less than 0.05). The livers of mice treated with the BM 10, 50, and 250 mg/kg showed a remarkable decrease in the number of lipid droplets compared with the vehicle control. The pancreas of mice treated with the BM 10, 50, and 250 mg/kg showed a remarkable increase in insulin concentration of β-cells compared with the vehicle control. In addition, the treatments of BM 10, 50, and 250 mg/kg actually increased the expression of AMPK-α2 compared with vehicle control. These results suggest that BM has a respectable anti-diabetic effect resulting from inhibition of blood glucose level and lipid level in serum and that consumption of BM may give a benefit for controlling diabetes mellitus in humans.