Humanc alcitonin (hCT) is a3 2-residue peptide hormone that can aggregate into amyloid fibrils and cause cellulart oxicity.I nt his study,w ei nvestigated the inhibition effects of ag roup of polyphenolic molecules on hCT amyloid formation. Our results suggest that the gallate moiety in epigallocatechin-3-gallate (EGCG), aw ell-recognized amyloid inhibitor,i sn ot criticalf or its inhibition function in the hCT amyloid formation. Ourr esults demonstrate that flavonoid compounds, such as myricetin, quercetin, and baicalein, that containv icinal hydroxyl groupso nt he phenyl ring effectively prevent hCT fibrillization. This structural feature may also be appliedt on on-flavonoidp olyphenolici nhibitors.M ore-over,o ur results indicate ap lausible mechanistic role of these vicinal hydroxylg roups which might include the oxidationto form aq uinone and the subsequent covalentl inkage with amino acid residuess uch as lysineo rh istidine in hCT.T his may furtherd isrupt the crucial electrostatic and aromatic interactions involved in the process of hCT amyloid fibril formation. The inhibition activity of the polyphenolic compounds against hCT fibril formationm ay likely be attributed to ac ombinationo ff actorss uch as covalentl inkage formation,aromatic stacking,a nd hydrogen bonding interactions.

Human calcitonin (hCT) is a 32-residue peptide that aggregates to form amyloid fibrils under appropriate conditions. In this study, we investigated the effect of the intramolecular disulfide bond formed at the N-terminal region of the peptide in the aggregation kinetics of hCT. Our results indicate that the presence of the disulfide