Inhibitors of alpha-Synuclein Fibrillation and Oligomer Toxicity in Rosa damascena: The All-Pervading Powers of Flavonoids and Phenolic Glycosides

Abstract

There is an intense search for natural compounds that can inhibit the oligomerization and fibrillation of alpha-synuclein (alpha-Syn), whose aggregation is key to the development of Parkinson's disease (PD). Rosa damascena is a medicinal herb widely used in Middle Eastern food, ceremonies, and perfumes. The herb is known to contain many different polyphenols. Here we investigated the existence of alpha-Syn fibrillation inhibitors in R. damascena extract. Different HPLC fractions of the extract were assessed in alpha-Syn fibrillation and toxicity assays. The most active fractions led to the formation of more alpha-Syn oligomers but with less toxicity to SH-SY5Y cells, according to MTT and LDH assays. LC-MS analysis identified gallic acid, kaempferol 3-glucoside, kaempferol-3-O-beta-rutinoside, and quercetin which were subsequently shown to be strong a alpha Syn fibrillation inhibitors. Our results highlight the benefits of R. damascena extract to combat PD at the population level.