The self-assembling of the amyloid β (Aβ) is considered an hallmark in the pathogenesis of Alzheimer’s disease (AD). Many efforts have been devoted in designing molecules able to halt disease progression by inhibiting Aβ selfassembly. We combine biophysical, biochemical and computational techniques to investigate the capacity of four optically pure components of the natural product silymarin (silybin A, silybin B, 2, 3-dehydrosilybin A, 2, 3-dehydrosilybin B) to inhibit Aβ aggregation. TEM analysis demonstrated that all the four investigated flavonoids prevent the formation of mature fibrils, however ThT assays, WB and AFM investigations showed that only silybin B was able inhibit the formation of small protofiber (considered the most toxic species) diverting the aggregation toward the formation of large amorphous aggregates. By using molecular dynamics (MD) simulations we observed that silybin B interacts …