Open Access Thesis
Date of Award
Nutrition and Food Science
PURIFICATION OF ALPHA-GLUCOSIDASE INHIBITORS FROM GRAPE EXTRACT
Advisor: Dr. Kevin Zhou
Major: Nutrition and Food Science
Degree: Master of Science
Diabetes and its complications are steadily growing and remain major causes of morbidity and mortality in the U.S. Intestinal Ã¡-glucosidases play a crucial role in controlling postprandial blood glucose. For this reason, one attractive prevention and/or treatment strategy for type-2 diabetes is the inhibition of Ã¡-glucosidase. The effectiveness of Ã¡-glucosidase inhibitors (AGI's) for diabetes treatment is well documented in numerous animal and human clinical studies. Grape pomace extract (GPE) has recently found in our laboratory to selectively inhibit alpha-glucosidases without inhibiting alpha-amylase, leading to inhibition of postprandial hyperglycemia in diabetic animals. The present study was designed to identify effective GPE by fractionating and isolating active compounds that inhibit alpha-glucosidases in a specific GPE. From enzyme assay testing, results revealed Fraction 1 active, showed 35% inhibition (p <0.05) compared to the positive control 87.64% and negative control -.565%. HPLC was conducted on F1, which yielded two potential active compounds (peaks) following ACN gradient system method. F1 will undergo future structure identification and elucidation.
Fractionation of GPE yielded a very small amount of active F1 for testing. Open column chromatography using HP20 and coarse C18 for scale-up of GPE separation but the resulting fraction failed to show significant inhibition on alpha-glucosidases. Further method development is needed if the collected peaks are not active compounds.
Shipp, Gayle M., "Purification of alpha-glucosidase inhibitors from grape extract" (2012). Wayne State University Theses. 198.