Antioxidant Quercetin 3-O-Glycosylated Plant Flavonols Contribute to Transthyretin Stabilization
Lidia Ciccone, Nicolò Tonali, Carole Fruchart‐Gaillard, Lucia Barlettani, Armando Rossello, Alessandra Braca, Elisabetta Orlandini, Susanna Nencetti
Abstract
Plants are rich in secondary metabolites, which are often useful as a relevant source of nutraceuticals. Quercetin (QUE) is a flavonol aglycone able to bind Transthyretin (TTR), a plasma protein that under pathological conditions can lose its native structure leading to fibrils formation and amyloid diseases onset. Here, the dual nature of five quercetin 3-O-glycosylated flavonol derivatives, isolated from different plant species, such as possible binders of TTR and antioxidants, was investigated. The crystal structure of 3-O-β-D-galactopyranoside in complex with TTR was solved, suggesting that not only quercetin but also its metabolites can contribute to stabilizing the TTR tetramer.