Effects of Bitter Melon (Momordica charantia) Extract on Glucose Transporters 2 and 4 Levels in Streptozotocin-induced Hyperglycaemic Rats

Glucose transporters (GLUTs) are essential for regulating glucose metabolism, with GLUT2 and GLUT4 serving as the primary transporters in muscle cells. In diabetic conditions, oxidative stress caused by free radicals damages glucose uptake into cells. Bioactive compounds in bitter melon, including triterpenoids, charantin, and conjugated linoleic acid, have been shown to have hypoglycaemic effects. Therefore, the present study aimed to evaluate the effect of bitter melon extract (Momordica charantia) on blood glucose, GLUT2, and GLUT4 in streptozotocin-induced hyperglycemic rats. The present study involved 15 male Wistar rats (white strain), 2 months old, with an average body weight of 130 grams. Diabetes was induced by administering streptozotocin at a dose of 60 mg/kg body weight. The animals were divided into three treatment groups, including the diabetic control group (P0), the diabetic group treated with 50% weight/volume (w/v) bitter melon extract (P1), and the diabetic group treated with 100% (w/v) bitter melon extract (P2). The extract was given orally at a dosage of 1 ml per rat for 14 days. Blood glucose concentrations were determined using a glucometer, whereas serum GLUT2 and GLUT4 levels were quantified with an ELISA kit. The results indicated that treatment P2 significantly lowered blood glucose levels compared to the diabetic control group, decreasing from 414.60 mg/dL (P0) to 223.60 mg/dL (P2). Serum GLUT2 concentrations declined from 21.51 (P0) to 16.50 (P2), and GLUT4 levels decreased from 19.94 (P0) to 17.60 (P2). These changes suggested an adaptive response intended to restore glucose homeostasis. Based on the present results, 100% w/v bitter melon extract concentration demonstrated a significant reduction in blood glucose, GLUT2, and GLUT4 levels in the serum of streptozotocin-induced diabetic rats.