A-type EGCG dimer, a new proanthocyanidins dimer from persimmon fruits, interacts with the amino acid residues of Aβ40 which possessed high aggregation-propensity and strongly inhibits its amyloid fibrils formation

A-type EGCG dimer is a new proanthocyanidins dimer from persimmon fruits. In the present study, we firstly examined the effects of EGCG and A-type EGCG dimer on A beta(40)-fibrillization, and then the detailed mechanisms behind the inhibitory effects of polyphenols on A beta(40) amyloid fibrils formation were investigated by PICUP assay, ESI-MS, NMR and molecular docking. Our results confirmed that A-type EGCG dimer exhibited stronger inhibitory effect on the formation of A beta(40) amyloid fibrils. We found that A-type EGCG dimer possessed more binding sites on A beta(40) peptide than EGCG. Notably, compared with EGCG, A-type EGCG dimer could interact with more amino acid residues which possessed obvious aggregation-propensity. And our results also suggested that the hydrophobic interaction was the principal driving force to inhibit the formation of A beta(40) amyloid fibrils by A-type EGCG dimer. We believed that our study could provide useful insights for the design of low-molecular weight inhibitors of A beta aggregation.