Evidence of enhanced inhibitory potential of Ferulic Acid Ethyl Ester towards modulating fibrillation and disassembling insulin fibrils

Abstract

The conversion of native conformation of protein into proteotoxic insoluble entities is not only confined to the protein misfolding diseases(PMDs) but also associated with pharmaceutically important proteins like insulin during the process of manufacturing/administration. Also all the neurodegenerative diseases are marked with increased level of oxidative stress. Thus finding anti-aggregation agents having anti-oxidant potential is utmost important to combat these complications. Herein, we performed biophysical, computational and imaging techniques to decipher the anti-aggregation propensity of a naturally occurring hydroxycinnamate- Ferulic acid ethyl ester(FAEE) that can cross blood brain barrier. Rayleigh light scattering(RLS) measurements, dye binding assays, Circular dichroism(CD) and Dynamic light scattering(DLS) measurements confirmed the efficient inhibition of insulin fibrillation by FAEE. The Stern-Volmer plot analysis reflected both the static and dynamic quenching mechanism of insulin by FAEE. Molecular docking and simulations results showed that FAEE bind and stabilizes the monomeric state of insulin with binding energy −6.3 kcal/mol. Moreover, the inhibiting effect of FAEE on the elongation phase of onward fibrillation in addition with triggering its fibril disassembling capability was also investigated. Both the stabilization of the protein structure and the restriction of monomers recruitment necessary for the fibrillar growth acts synergistically in providing FAEE its anti-aggregation effect. Appearance of significantly lesser and shortened fibrils in FAEE presence was depicted by transmission electron microscopy. Overall, our finding establishes for the first time the anti-amyloidogenic role of lipophilic FAEE which can cross blood brain barrier. These findings may inspire the development of FAEE based formulations that could possibly treat amyloid-related diseases.