Structure-function relationships governing polyphenol bioactivity with respect to plasma membranes

This project aims to investigate polyphenol binding to lipid membrane surfaces with a view to understanding how polyphenol structure and aggregation within the gastrointestinal tract (GIT) affects the bioavailability of these nutraceuticals. Polyphenols are molecules of nutritional significance that are able to act to reduce oxidative stresses that can otherwise cause chronic diseases like cardiovascular disease, cancer and neurodegenerative disorders. The nutritional benefit of polyphenols is well documented, both in animal and human nutrition. They also have been shown to have antimicrobial properties. However, these are affected by protein binding and polyphenol interaction with the GIT wall, i.e. the intestinal epithelium. How polyphenol structure and aggregation changes within the GIT environment influences the ability of the polyphenol to be used by the body is not well defined. Although we are beginning to understand the aspects of polyphenol biological activity that are affected by protein binding, our understanding of the polyphenol-lipid membrane interaction and its role in biological activity is not well understood.

This project explores the design and fabrication of effective models of the epithelial apical plasma membrane that are amenable to study by neutron reflectometry (NR) and other surface analytical techniques. Epithelial cells form barriers between tissues with the role of protecting and enclosing organs found, for example, in the gut wall and the outer surface of the body. The development of models will allow the expansion of NR to nutrient and drug absorption and to furthering our understanding of how and why molecules can cross these barriers, and will be used here in the study of polyphenol interactions within the GIT. In time, this work could be extended to modelling other membrane structures found in human and animal cells, such as the lateral and basal membranes.