Access Type

Open Access Thesis

Date of Award

January 2012

Degree Type

Thesis

Degree Name

M.S.

Department

Nutrition and Food Science

First Advisor

Kequan Zhou

Abstract

ABSTRACT

PURIFICATION OF ALPHA-GLUCOSIDASE INHIBITORS FROM GRAPE EXTRACT

by

GAYLE SHIPP

August 2012

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 á-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 á-glucosidase. The effectiveness of á-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.

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