Stereospecificity Membrane Impact of Two Catechins on Red Blood Cells.

Catechins are characterized by a basic structure consisting of two benzene rings and a hydropyran heterocyclic ring. In (-)-epicatechin (ECT), the substituents in C2 and C3 of the dihydropyran ring are in cis conformation, whereas in (+)-catechin (CT), they are in trans conformation. Catechins tend to interact with membrane proteins, affecting their activity and/or function and metabolic processes. In this study, the impact of CT and ECT on erythrocyte membrane and cell functions was analyzed. Surprisingly, although the two compounds have a very similar structure that differs only in the orientation of the hydroxyl group in C3, they promote different effects on anion exchange through the phospholipid bilayer and on the release of ATP from cells. Anion transport mediated by Band 3 protein is reduced in the presence of CT compared with ECT which conversely increases it, and this observation aligns with the mechanisms of action we hypothesized in silico for the two compounds. Finally, ECT causes an increase in intracellular ATP levels unlike CT, and both molecules cause a decrease in ATP released from the erythrocyte. These findings could pave the way for further studies aimed at better understanding of the potential properties and structure-activity relationships of these molecules.