Makonnen, Eyasu (Professor)Mekonnen, Yalmetsehay(Professor)Toma, Alemayehu2018-06-202023-11-292018-06-202023-11-292016-03http://etd.aau.edu.et/handle/123456789/2173Background: Moringa stenopetala has been used in traditional health systems to treat diabetes mellitus. One of the successful methods to prevent onset of diabetes is to control postprandial hyperglycemia by inhibition of α-glucosidase and pancreatic α-amylase activities, resulting in the aggressive delay of the carbohydrate digestion of absorbable monosaccharides. The aim of the present study was to investigate the effect of the extract of the leaves of Moringa stenopetala on glycation control, α-glucosidase, pancreatic α- amylase, pancreatic lipase, and pancreatic cholesterol esterase activities, and, therefore find out the relevance of the plant in controlling blood sugar and lipid levels. Methods: The dried leaves of Moringa stenopetala were extracted with hydroalcoholic solvent and the resulting extract was dried using rotary vapor under reduced pressure. The dried extracts were determined for the total phenolic compounds, flavonoid content and condensed tannins content using Folin-Ciocateu’s reagent, AlCl3 and vanillin assay, respectively. The dried extract of plant-based food was further quantified with respect to intestinal α-glucosidase (maltase and sucrase) inhibition and pancreatic α-amylase inhibition by glucose oxidase method and dinitrosalicylic (DNS) reagent, respectively. Aqueous ethanol and n-butanol fraction of Moringa stenopetala leaves (500mg/kg body weight) and metformin (150 mg/kg body weight) were administered to diabetic rats. Blood glucose, lipid profiles, liver and kidney function were examined after 14 days of experiment. The antioxidant activity was determined using 2, 2′- diphenyl-1- picrylhydrazyl (DPPH) assay. Antiglycation activity was determined using inhibition of formation of advanced glycation end products (AGE), level of Nε-(carboxymethyl) lysine (CML), the level of fructosamine, and the formation of amyloid cross β-structure in bovine serum albumin after incubation with fructose. The protein oxidation was examined using the level of protein carbonyl content and thiol group. Results The present phytochemical analysis indicated that the flavonoid, total phenol, and condensed tannin contents in the extract were 71.73±2.48 mg quercetin equivalent/g of crude extract, 79.81±2.85 mg of gallic acid equivalent/ g of crude extract, 8.82±0.77 mg catechin equivalent/g of crude extract, respectively. The extract inhibited intestinal sucrase more than intestinal maltase with IC50 value of 1.47±0.19 mg/ml. It also slightly inhibited pancreatic α-amylase, pancreatic lipase and pancreatic cholesterol esterase. Oral administration of aqueous ethanol and n-butanol extract of Moringa stenopetala leaves (500 mg/kg body weight) and metformin (150mg/Kg) significantly reduced blood glucose level (P<0.05), significantly improved serum lipid profiles, liver enzymes and kidney functions in diabetic rats after 14 days. The extract also increased in size of islet of Langerhans in diabetic rats. Moringa stenopetala leaves significantly inhibited the formation of AGEs by approximately 54.75+0.94% at a concentration of 2mg/ml. Furthermore, Moringa stenopetala leaves extract reduced the levels of fructosamine, amyloid cross β-structure and Nε-(carboxymethyl) lysine (CML) . The leaves also prevented oxidative protein damage, including effects on protein carbonyl formation, thiol oxidation of BSA and antioxidant activity in DPPH assay Conclusion: The present results demonstrated the beneficial biochemical effects of Moringa stenopetala leaves extract by inhibiting intestinal α-glucosidase, pancreatic cholesterol esterase and pancreatic lipase activities. A daily supplement intake of the leaves of Moringa stenopetala may help in reducing diabetes induced glycation, hyperglycemia and hyperlipidemia. Keywords: Antihyperglycemic, Antihyperlipidemic, antiglycation, Moringa stenopetala, enzyme inhibitionenAntihyperglycemic; Antihyperlipidemic; Antiglycation; Moringa stenopetala; Enzyme inhibitionThesis