ABSTRACT

This study  investigated the effects of crude extract and fractions from Moringa oleifera leaves on glucose transport proteins, AMPkinase,Na⁺/K⁺-ATPase and other parameters in streptozotocin induced diabetes male wistar rats using acceptable chemical and biochemical methods. Crude extract and active fractions of M. Oleifera were subjected to gas chromatography- mass spectrophotometer (GCMS) for identification of bioactive compounds in the plant. The animal experiment was carried out in two phases.  In  Phase 1, 40 male Wistar rats  placed in 8 groups of five (5) rats each were used. Group 1 (normal control), group 2(drug control), group 3 (diabetic control), group 4 (Dimethylesulphuroxide control).Group 5and 6 were administered 1000mg/kgbwt and500mg/kgbwt of aqueous extract while group7 and 8 were administered 1000mg/kgbwt and 500mg/kgbwt of methanol extract respectively. Result obtained showed no significant difference (P>0.05) in the relative heart, lungs, liver and intestinal weight. The blood glucose level, glycated heamoglobin, cholesterol, triacylglycerol, LDL-Cholesterol, VLDL-Cholesterol levels and α-amylase activities increased significantly (P< 0.05) in group 3 and 4 when compared to group 1, 2, 5, 6, 7 and 8. Treatment with glibenclamide and different doses of crude extract in groups 2, 5, 6, 7 and 8 indicated a significant(P<0.05) increase in HDL-Cholesterol level, lipoprotein lipase, phosphate dehydrogenase and Na⁺/K+-ATPase activities when compared to group 3 and 4. The result revealed a significant increase (P<0.05) in Glucose Transport Protein 1 and 4 and AMPkinase activities in group 2, 5, 6, 7 and 8 respectively when compared to group 3 and 4. A total of 45 animals placed in 9 experimental groups of 5 animals each were used in phase 2.Group 1 (normal control), group 2 (drug control), group 3 (diabetic control), group 4(1000mg/kgbwt of aqueous extract) while group 5-9 received fractions 1- 5 respectively for 28 days. Result obtained showed no significant difference (P>0.05) in the relative heart, liver, kidney, lungs and intestinal weight.  Fractions 3,4 and 5 significantly decreased (P<0.05) the glucose level, α-amylase activity, cholesterol, triacylglycerol, LDL-Cholesterol and VLDL-Cholesterol except HDL-Cholesterol when compared with fractions 1 and 2 respectively. The result revealed that fractions 3, 4 and 5 showed a significant increase (P<0.05) in lipoprotein lipase, phosphate dehydrogenase and Na⁺/K⁺-ATPase activities when compared with group 3, fractions 1 and 2 respectively. GLUT 1,GLUT 4 and AMPkinase activities were significantly increased(P<0.05) in groups administered glibenclamide, aqueous extract and fractions 3, 4 and 5 when compared with group 3, fraction 1 and 2 respectively.Fractions1 and 2did not show any significant difference (P >0.05) with the diabetic control group in all the parameters studied. Histopathological investigation of the pancreas showed that the crude extract and fractions 3, 4and 5 regenerated and restored the histoarcheteture of the pancreatic acini and reduced the vacuolations of  Langerhans islets cell resulting in the absence of necrosis near to normal. GC- MS analysis of crude extract and fractions 3,4 and 5 showed the presence of many bioactive compound out of which hexadecanoic acid, Octadecanoic acid, Octadecenoic acid, Palmitic acid, and Octadecenoic acid ethyl ester were part. This indicated that Crude extract and fractions of M.Oleifera leaves ameliorated the studied indicators of diabetes and its complications  in STZ- induced diabetic male wistar rats. The possible synergetic action of the bioactive agents present in the leaves might be responsible for the effects.