Protective Effect of Quercetin on Amyloid-Induced Alterations in Lipid Bilayer Integrity

The present study employs molecular dynamics simulations to investigate the interactions between quercetin, amyloid fibrils, and POPC lipid bilayers. The results demonstrate that quercetin does not significantly affect the molecular organization of the bilayer, while IAPP fibrils induce substantial structural changes, particularly in the outer monolayer. Quercetin mitigates these effects by reducing the impact on headgroup and glycerol regions and causing a more superficial positioning of IAPP. Additionally, quercetin slightly decreases the order of sn-2 acyl chains, indicating a disordering effect. In a ternary system with POPC, quercetin, and IAPP, the reduction in the deuterium order parameter of sn-2 acyl chains is less pronounced, underscoring quercetin's protective role. Unlike IAPP, ApoAI and insulin fibrils undergo significant structural reorganization in the membrane-bound state. Quercetin attenuative effects are observed only with ApoAI, highlighting its potential as a protective agent against amyloid-induced membrane disruption. These findings provide valuable insights into the interactions between polyphenols, amyloid fibrils, and lipid membranes, contributing to the understanding of membrane-associated amyloid pathologies.