Hesperetin Inhibits Aβ Early Aggregation by Disrupting the Continuity of the β-Sheet Structure

Abstract The misfolding and pathological aggregation of amyloid-β (Aβ) into insoluble amyloid deposits are closely associated with Alzheimer’s disease (AD). Inhibiting early Aβ assembly is a critical strategy for the development of antiamyloid therapeutics. Hesperetin (HST), a natural flavanone abundant in citrus fruits, has been reported to inhibit Aβ fibrillogenesis and reduce Aβ-associated cytotoxicity. However, the molecular mechanism underlying HST-mediated inhibition of Aβ aggregation remains unclear. In particular, whether HST acts through mechanisms similar to other natural compounds or employs a distinct inhibitory strategy is yet to be determined. Here, we employed replica exchange molecular dynamics (REMD) simulations to investigate how HST modulates Aβ early aggregation and β-sheet assembly at the atomic level. The results demonstrate that HST disrupts the continuity of β-sheet structures within Aβ dimers, as evidenced by restricted β-strand extension. Mechanistically, HST preferentially interacts with aggregation-prone regions of Aβ through a synergistic interaction network of hydrogen-bonding, hydrophobic, π–π stacking, and cation–π interactions. Notably, HST-mediated hydrogen bonding with the Aβ backbone perturbs the local hydrogen-bonding environment required for β-sheet extension, while cooperative nonpolar and aromatic interactions further stabilize HST-bound conformations and weaken intra- and intermolecular interaction networks involved in Aβ self-assembly. Collectively, these findings reveal a specific mechanism by which HST regulates Aβ aggregation through disruption of β-sheet continuity, which provides atomic-level insights into the antiamyloid activity of natural flavanones.