The effect of Gold Nanoparticles synthesized from hibiscus mucilage on the amyloid fibrils formation in alpha-lactalbumin

Amyloid fibrils are formed by incomplete, partial folding or self-assembly of proteins facilitated by hy-drophobic and electrostatic interactions. Amyloid fibrils are involved in pathogenesis of many neurode-generative diseases such as Alzheimer, Huntington, and Parkinson diseases.Hibiscus sabdariffa is a natural plant, which has antioxidant properties due to the presence of phenols, flavonoids, and anthocyanins. Green Nanoparticles have more purity and fewer side effects with respect to the chemical Nanoparticles. In this study, the chaperone effect of the gold nanoparticles on the amyloid aggregations is demonstrated by sev-eral approaches including intrinsic fluorescence intensity, sodium dodecyl sulfate polyacrylamide gel elec-trophoresis (SDS-PAGE), and transmission electron microscopy (TEM).ThT binding assay results showed that the formation of the amyloid fibrils is decreased by adding AuNPs in a concentration-dependent method. In agreement with this, TEM results also showed that amyloid fibril formation is considerably decreased in the presence of gold nanoparticles, which leads to the formation of non-toxic amorphous aggregations. The fluorescence intensity measurements indicate that fluorescence intensity of protein samples are significantly reduced in the presence of Nanoparticles due to reduction in the Trp residues.The results of SDS-PAGE re-vealed that by increasing the concentration of AuNPs, interaction of reduced protein with nanoparticles is increased. As well, the size of protein aggregation is decreased and thus electrophoresis mobility is increased. Therefore, the green AuNPs that are extracted from the mucilage of the Hibiscus, are able to reduce the rate of the amyloid formation of α-lactalbumin in a concentration-dependent approach.

کلیدواژه ها:

Amyloid Fibrils ، Hibiscus sabdariffa ، Mucilage ، Gold Nanoparticle ، α-Lactalbumin