الفهرس | Only 14 pages are availabe for public view |
Abstract The goal of the present work was to investigate the anti-diabetic and anti-lipidemic properties of momordica charantia fruit extract in experimentally induced diabetes and to study the possible physiological mechanisms of action of this tested plant. Adult male albino rats (120-160 g) were allocated for the present study. After acclimatization period of two weeks, each animal was injected intra-peritoneally with a single dose of 100 mg/kg B.Wt. alloxan monohydrate dissolved in citrate buffer (pH 4.5). Ten days after alloxan injection, rats were screened for measuring blood glucose level. The mild diabetic rats (rats having serum glucose level ranging from 180-300 mg/dl) were divided into three groups, the first group was given distilled water and considered as diabetic control. The second group received rosiglitazone (Avandia), an oral hypoglycemic drug, to compare its effect with bitter melon. Other 2 groups of normal animals were kept under the same laboratory conditions, one regarded as a normal control for the diabetic groups and the other received the plant extract to test its effect in normal condition. All treatments were applied orally by gastric intubation daily for 4 weeks. At the end of the experimental period, oral glucose tolerance test was performed before sacrifice. After sacrifice blood was collected for the determination of Serum insulin, blood glycohemoglobin (HbA1c) %, ALT, AST and lipid profiles (triglycerides, total cholesterol, LDLcholesterol and HDL-cholesterol). Livers and pancreata were quickly 99 removed after dissection for measuring glycogen content and studying the histopathological changes respectively. To suggest the possible mechanisms of hypoglycemic action of bitter melon, its effects on peripheral glucose uptake by rat diaphragm and insulin release from isolated islets of Langerhans were studied in vitro, in addition to its effect on Intestinal glucose absorption in situ. These were compared to control studies. An increase in Serum glucose, ALT, AST, triglycerides, Total cholesterol, LDL-cholesterol and Blood glycohemoglobin, while a decrease in Body weight, Serum insulin, liver glycogen and serum HDL-cholesterol were observed in alloxan diabetic control rats as compared to the normal control group. Treatment of diabetic rats with either bitter melon or rosiglitazone produced opposite results denoting ameliorative effect on carbohydrate and lipid metabolism. Concerning the in vitro and insitu experiments, bitter melon found to increase peripheral glucose uptake by rat diaphragm, have insulinotropic effect and decrease intestinal glucose absorption, while rosiglitazone increased only glucose uptake by rat diaghragm. With regard to the histopathological changes, microscopic examination of the pancreas showed destructed β cells and vacuolated cytoplasm in diabetic control rats after 4 weeks experimental period. On the other hand, treatment of diabetic rats with either bitter melon or rosiglitazone increased β cell numbers in the pancreas. 100 Results obtained from diabetic rats treated with bitter melon were significant as compared to diabetic control and rosiglitazone. In conclusion, the present study revealed that bitter melon has both pancreatic (insulinotropic) and extrapancreatic (insulin mimetic) mechanisms of anti-diabetic effect so, it may act as a good alternative in treatment of diabetes mellitus. |