Skip to Main Content
 

Global Search Box

 
 
 
 

ETD Abstract Container

Abstract Header

Interaction of (-)-epigallocatechin-3-gallate with serum albumin in the presence or absence of glucose

Abstract Details

2014, Doctor of Philosophy, Miami University, Chemistry and Biochemistry.
(-)-Epigallocatechin-3-gallate (EGCg) has been epidemiologically associated with reduced risks of chronic diseases. The health benefits of EGCg are greatly affected by interactions with plasma proteins. To better understand EGCg bioactivities, this work investigated the site-specific interaction between EGCg and bovine serum albumin (BSA), the effects of EGCg on human serum albumin (HSA) glycation, the effects of EGCg on heme-HSA complexation under glycemic pressure, and the preparation of (-)-epigallocatechin (EGC) from green tea extract. This dissertation is composed of four parts. First, I characterized the site-specific interaction between EGCg and BSA. Fluorescence intensity and lifetime showed that the binding site for EGCg was located in the hydrophobic pocket on subdomains IIA and IIIA. Circular dichroism and molecular simulation confirmed a requirement for both flavan-3-ol and galloyl moieties and suggested a potential mechanism for the stabilization of EGCg by serum albumin. In the second part, I evaluated the anti-glycation/glycation activities of EGCg in a HSA/glucose model. Levels of carbonyls, fluorescence and native PAGE indicated that EGCg bioactivities were dictated by glucose level, and were secondarily affected by EGCg concentration and time of exposure to EGCg. This work provides a comprehensive evaluation of EGCg bioactivities and highlights the potential value of EGCg treatment in patients under severe glycemic pressure. In the third part, I investigated the effects of EGCg on heme-HSA complexation under glycemic pressure. I used spectrophotometric titration to determine the dissociation constant for heme-HSA complexation. Treatments by physiologically relevant concentrations of EGCg protected and reversed the heme binding affinity of HSA. Fluorescence measurement suggested that EGCg-HSA specific interaction was important for the restorative effect on heme-HSA complexation. In the last part, I describe the preparation of EGC from green tea extract. I isolated crude EGCg from the extract by silica gel chromatography, and then hydrolyzed crude EGCg by tannase. EGC was isolated and purified by Sephadex LH-20 chromatography using the hydrolysis products that were extracted by ethyl acetate. Purified EGC was characterized by HPLC and ESI-MS.
Ann Hagerman, E (Advisor)
Carol Dabney-Smith (Committee Chair)
Neil Danielson, D. (Committee Member)
Rick Page (Committee Member)
Annette Bollmann (Committee Member)
130 p.

Recommended Citations

Citations

  • Li, M. (2014). Interaction of (-)-epigallocatechin-3-gallate with serum albumin in the presence or absence of glucose [Doctoral dissertation, Miami University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=miami1404916949

    APA Style (7th edition)

  • Li, Min. Interaction of (-)-epigallocatechin-3-gallate with serum albumin in the presence or absence of glucose. 2014. Miami University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=miami1404916949.

    MLA Style (8th edition)

  • Li, Min. "Interaction of (-)-epigallocatechin-3-gallate with serum albumin in the presence or absence of glucose." Doctoral dissertation, Miami University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=miami1404916949

    Chicago Manual of Style (17th edition)