Role of dietary antioxidant (-)-epicatechin in the development of β-lactoglobulin fibrils

Under specific physico-chemical conditionsβ-lactoglobulin is seen to formfibrils structurally highly similar tothose that are formed by the amyloid-like proteins associated with neurodegenerative disorders, such asAlzheimer and Parkinson diseases. In the present study we provide insights on the possible role that the dietaryflavonoid (−)-epicatechin plays onβ-lactoglobulinfibril formation. Fibril formation is induced by keepingβ-lactoglobulin solutions at pH 2.0 and at a temperature of 80 °C for 24 h. Atomic Force Microscopy measurementssuggest that, by adding (−)-epicatechin in the solution,fibrils density is visibly lowered. This last observation isconfirmed by Fluorescence Correlation Spectroscopy experiments. With the use of Fourier Transform IR spectros-copy we monitored the relative abundances of the secondary structures components during the heating process.We observed that in the presence of (−)-epicatechin the spectral-weight exchange between different secondarystructures is partially inhibited. Molecular Dynamics simulations have been able to provide an atomistic explana-tion of this experimental observation, showing that (−)-epicatechin interacts withβ-lactoglobulin mainly viathe residues that, normally in the absence of (−)-epicatechin, are involved inβ-sheet formation. Unveilingthis molecular mechanism is an important step in the process of identifying suitable molecules apt atfinelytuningfibril formation like it is desirable to do in food industry applications