A Molecular Dynamics Study on the Interaction of Tea Catechins and Theaflavins with Biological Membranes

Molecular dynamics simulations were performed to study the interactions of bioactive catechins and theaflavins commonly found in tea with lipid bilayers, as a model for cell membranes. Previously, multiple experimental studies rationalized the anticarcinogenic, antibacterial, and other beneficial effects of these compounds in terms of physicochemical molecular interactions with cell membranes. To contribute toward understanding the molecular role of tea polyphenols on the structure of cell membranes, simulation results are presented for seven catechins and three theaflavins in lipid bilayer systems which are both pure (POPC) and representative of HepG2 cancer cells (POPC and POPE). Our simulations show that the catechins and theaflavins evaluated have a strong affinity for the lipid bilayer \textit{via} hydrogen bonding to the bilayer surface, with many of the catechins able to penetrate beneath the surface. Epigallocatechin-gallate (EGCG) and Theaflavin-3,3'-digallate showed the strongest interaction with the lipid bilayers based on the number of hydrogen bonds formed with lipid headgroups. The simulations also provide insight into the functional characteristics of the tea compounds that distinguish them as effective compounds to potentially alter the lipid bilayer properties. The results on the hydrogen-bonding effects may contribute to a better understanding of proposed multiple molecular mechanisms of the action of catechins and theaflavins in microorganisms, cancer cells, and tissues.