Modulation of amyloid fibril formation of plasma protein by saffron constituent "safranal": Spectroscopic and imaging analyses

Anti-amyloidogenic activity of safranal towards induced HSA amyloids has been observed using a variety of techniques including fluorescence, UV-visible, CD, DLS and microscopies. The HSA solution was pre-incubated at 65 °C for 120 h and, in between, the growth of amyloid fibrils, using ThT aggregation kinetics, was monitored at different time intervals. It was found that the amyloid fibril formation of HSA diminishes in presence of safranal and the inhibition was concentration dependent. The surface hydrophobicity of HSA amyloid fibrils also decreased in presence of safranal. The increased CR binding of HSA fibrils also decreased and high concentration of safranal causes the CR binding to resemble like that of native HSA. Both RLS and turbidity intensities were also in inverse relation to the safranal concentration. Safranal also has a good impact to protect the secondary structure of incubated HSA. From the electron microscopy it was seen that the fibrillar network of HSA amyloids gradually vanishes as the concentration of safranal increased. The largely decreased population of HSA aggregates in safranal containing solution as compared to the one without it also suggests the inhibition of formation of large fibrillar aggregates.