Natural compound safranal driven inhibition and dis-aggregation of α-synuclein fibrils

Abstract

Self-assembly of α-synuclein (α-Syn) is linked with a variety of neurodegenerative diseases collectively called as α-synucleiopathies. Therefore, discovering suitable inhibitors for this self-association process of α-Syn is a subject of intense research. In this background, we have demonstrated here that the natural compound, Safranal, delays/inhibits α-Syn fibrillation/aggregation, and we have also characterized its mode of action. The α-Syn fibrillation/aggregation kinetics studies in combination with TEM studies demonstrated that Safranal effectively inhibits α-Syn fibrillation/aggregation. NMR studies revealed that Safranal binds with α-Syn and stabilizes the monomeric protein. ANS fluorescence and CD measurements indicated that Safranal binds to the hydrophobic residues of the protein and causes delay in the formation of β-sheet rich structures which are crucial for the fibrillation to occur. The results obtained from fluorescence quenching, NMR and ANS binding assays, when analysed taking into consideration the molecular structure of Safranal provide valuable insights into the mechanism of inhibition of α-Syn fibrillation/aggregation. We infer that inhibition of α-Syn fibrillation/aggregation is primarily driven by hydrophobic interactions between Safranal and the protein. Further, Safranal is also seen to dis-aggregates pre-formed α-Syn fibrils. These findings implicate that Safranal could become a potent therapeutic intervention in Parkinson's disease and other protein aggregation related disorders.