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www.diabetes.org 23,600,000 Diabetics 7 th Leading Cause of Death Estimated $218 Billion 5.2X higher medical expenditures 71,000 amputations 1.6 million new cases per year
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Type II Diabetes is most common form › Fasting blood glucose >126 mg/dL (NIH) › Excessive glucose levels in the blood causes health problems Two different causes › The body does not produce enough insulin › The body’s cells become resistant to insulin Increasing risk › Obesity and lack of physical activity › Genetics › High fat diet and alcohol intake › High blood pressure 6.2 MILLION PEOPLE ARE UNDIAGNOSED 54 MILLION PEOPLE ARE PRE-DIABETIC 54 MILLION PEOPLE ARE PRE-DIABETIC
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Drug Therapies for Diabetes Mellitus Biguanides such as Metformin (Glucophage) decrease the production of glucose in the liver. Sulfonylureas (Amaryl, DiaBeta, Glucotrol, Micronase) and Meglitinides (Prandin, Starlix) stimulate the pancreas to release more insulin. Thiazolidinediones (Actos, Avandia) increase the sensitivity of fat and muscle cells to insulin. Inhibitors of digestive enzymes (α-amylase and α- glucosidase) slow the absorption of carbohydrates. 4
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α-Amylase › Digests starches and oligosaccharides › Secreted by the pancreas, component of saliva › Located in mouth and small intestine α- Glucosidase › Digests starches and oligosaccharides › Located in the epithelium of the small intestine
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OH O CH 2 OH Lumen of the Small Intestine Epithelial Brush Border of the Small Intestine Enzyme OH O CH 2 OH OH O CH 2 OH OH O CH 2 OH
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Obtained from the fermentation processes of a microorganism, Actinoplanes utahensis Reduces postprandial hyperglycemia › Oligosaccharide that competitively and reversibly inhibits the activity of α-glucosidase and α-amylase Issues: › Cost › Side effects, including gastrointestinal disturbances (stomach distress, diarrhea, bloating, etc.) and nausea
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Lumen of the Small Intestine Epithelial Brush Border of the Small Intestine Enzyme Inhibitor: Acarbose
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A class of plant secondary metabolites Primary function is to provide protection to plants against biological attacks Are known for their biological activities Flavone backbone structure
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Amylase Inhibition Assay α- Amylase Inhibition Assay Common structural features of flavonoids to inhibit α-amylase Catechin Epicatechin EGC 10 C R6 R7 R4΄ R5΄ Flavonoids inhibit α-amylase only if they contain (Lo Piparo et al., 2008): 4-oxo-flavonoid nucleus as C-ring C2-C3 double bound conjugated to the 4-keto group Specific pattern of OH groups: R6 or R7 of the A-ring R4’ or R5’ of the B- ring
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Belong to a subgroup of bioflavonoids called “Flavan-3-ols” Chosen because of structural components Monomers can form dimers or trimers that are structurally similar to acarbose Found in grape seed and tea extracts, for example Catechin
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Inhibition of α-amylase and α-glucosidase by specific flavonoids during the digestion of starches helps control post-prandial hyperglycemia and ultimately Type II Diabetes Mellitus.
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Incubate enzyme with test compound Add derivatized starch (provided in an assay kit) Read fluorescence in 96- well plate reader at Ex/Em 485/530 nm every 1 minute for 15 minutes Determine inhibition through IC 50 calculation http://www.cryst.bbk.ac.uk/pps97/assignments/projects/gaz erro/amylase.gif
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IC 50 The IC 50 value is defined as the concentration of inhibitor required to inhibit 50% of the α-amylase activity… …which is a measure of the inhibitor’s relative effectiveness
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μMμM μMμM μMμM μMμM μMμM Concentration of Inhibitor Slopes converted to percentage activity
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IC 50 = 9.44 ± 0.70 μg/ml IC 50 = 7.37 ± 0.26 μg/ml
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IC 50 = 9.44 ± 0.70 μg/ml IC 50 = 7.37 ± 0.26 μg/ml Catechin Epicatechin
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IC 50 = 7.37 ± 0.26 μg/ml α-amylase activity (%) IC 50 = 44.62 ± 0.52 μg/ml Epigallocatechin Gallate
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IC 50 = 7.37 ± 0.26 μg/ml α-amylase activity (%) IC 50 = 44.62 ± 0.52 μg/ml IC 50 = 356.73 ± 31.60 μg/ml α-amylase activity (%)
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356.73
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Incubate enzyme with test compound Add substrate p- nitrophenyl ß-O-D- glucopyranoside (pNPG) and incubate Read absorbance in 96-well plate reader at 405 nm Determine IC 50 http://www.rcsb.org/pdb/explore/explore.do?structureId=2ZE0
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IC 50 = 102.67 ± 3.77 μg/ml
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Preliminary experiments for a human trial Variables: › Amount of carbohydrate (starch) challenge › Nature and dose of test compound(s) › Time point of administration of test compound(s) vis-à-vis carbohydrates/starch › Blood collection time points
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Peak Area (AUC)= 21.9 With Inhibitor Peak Area (AUC)= 21.7 Carbohydrate Only
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α-Glucosidase and α-Amylase: In Vitro Studies › Confirm in vitro results (n=3, statistical evaluation) › Vary inhibitor concentration to determine K i for select bioflavonoids/extracts Human Studies › Optimize conditions Carbohydrate dose Supplement (mixture) to test Dose of supplement Administration time › Conduct trial, measure post-prandial glycemia and insulinemia Pancreatic Lipase (fat absorption): › Initial studies (in vitro) and optimization in Fall/Winter › Preliminary in vivo studies (time permitting)
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Dr. Meltem Yilmazer-Musa Dr. Balz Frei Mary Garrard Dr. Dan Sudakin Dr. Alex Michels Linus Pauling Institute Howard Hughes Medical Institute Undergraduate Research and Innovation, Scholarship and Creativity USANA › http://en.wikipedia.org › http://www.webmd.com/ › www.diabetes.org › Peters, A. and Votey, R. “Diabetes Mellitus, Type 2- A Review”. WebMD. http://emedicine.medscape.com/article/766143. Accessed 8/19/2010 › www.nih.gov
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Morin Baicalein Scutellarein Myricetin
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American Heart Association Waist circumference greater than 40 in (men) or 35 inches (women) Elevated blood pressure, equal to or greater than 130/85 Elevated fasting glucose, greater than 100 mg/dL Reduced HDL, less than 40 gm/dL (men), and 50 mg/dL (women) Elevated blood triglycerides, above 150 mg/dL
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