Antioxidant Quercetin 3-<i>O</i>-Glycosylated Plant Flavonols Contribute to Transthyretin Stabilization

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.

Keywords

• transthyretin
• TTR
• quercetin 3-<i>O</i>-glycosylated derivatives
• amyloidosis
• antioxidant
• plant bioactive metabolites