Electroanalysis of the interaction between (-)-epigallocatechin-3-gallate (EGCG) and amyloid-beta in the presence of copper

The misfolding of amyloid-beta (A beta) peptide is one of the pathological hallmarks of Alzheimer's disease (AD). Polyphenols are strong antioxidants and metal chelators, with characteristics that are of beneficial therapeutic values for their development as candidates targeting neurodegenerative and metal-induced diseases. We have demonstrated here the electrochemical properties of a green tea component, (-)-epigallocatechin-3-gallate (EGCG), and its potent activity on A beta peptides. Characterization of early interactions (<= 48 h) between EGCG and A beta was conducted using square wave voltammetry (SWV). The interaction of Cu(II) ions with the Tyr-10 residue of A beta was shown to be affected by surrounding His residues. Morphological changes due to the binding of EGCG and Cu(II) were also elucidated using transmission electron microscopy (TEM). Electroanalytical techniques are promising for facilitating the investigation of metals and flavonoids in drug screening studies.