Finding Optimum Fruit Extracts to Inhibit the Aggregation of Amyloidogenic IAPP
Authors:Taylor Arhar , Pei-Yu (Margaret) Kao
Mentor:David Moffet , Professor of Biochemistry , Loyola Marymount University
Current literature suggests that the aggregation of Islet Amyloid Polypeptide (IAPP, amylin) plays a direct role in the death of pancreatic B-islet cells in type II diabetes, and that the inhibition of aggregation may slow or prevent the progression of type II diabetes. In this study, we screened 13 fruits for inhibiting the aggregation of IAPP. The fruits were selected based on their accessibility to the public and their relative costs; we chose the most inexpensive and easily accessible fruits. We performed an ethyl acetate extraction of each whole fruit sample and tested for inhibition using a Thioflavin T binding assay. In addition, Circular Dichroism was also utilized to monitor and to test the in vitro inhibitory potential of each extract. Atomic force microscopy was used to visualize the formation of amyloid fibers of each fruit extract and IAPP, and of IAPP alone. Finally, the extracts were analyzed for their ability to protect living mammalian cells from the toxic effects of IAPP in MTT Assays. After reducing the concentration of the extracts by 100-fold dilution, grape, blueberry, and pomegranate were found to be effective in inhibiting aggregation. It was found that pomegranate alone still showed significant inhibition of aggregation at a 250-fold dilution. Upon mixing the most effective fruits at this high dilution, fruit mixes showed similar inhibition to pomegranate alone.