Studies have shown that the level of ascorbic acid (AA) is reduced in the brain of Alzheimer's disease (AD) patients. However, its effect on amyloid-β 1-42 (Aβ42) aggregation has not yet been elucidated. Here we investigated for the first time the effect of AA on Aβ42 aggregation using fluorescence assay, circular dichroism, atomic force microscopy, isothermal titration calorimetry, ligand docking, and molecular dynamics. Our results showed that the fibril content decreases in the growth phase when the peptides are co-incubated with AA. AA molecules bind to Aβ42 peptides with high binding affinity and a binding site for AA between the β-strands of Aβ42 oligomers prevents the stack of adjacent strands. We demonstrate the inhibitory effect of AA on the aggregation of Aβ42 and its molecular interactions, which can contribute to the development of an accessible therapy for AD and also to the design of novel drugs for other amyloidogenic diseases.
Keywords: Alzheimer's disease; Amyloid inhibitor; Ascorbic acid; Beta-amyloid aggregation.
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