Publications Repository - Gdańsk University of Technology

Quercetin, one of the most abundant flavonoids in plant-based foods, commonly occurs in nature in various glycosylated forms. There is still a less explored aspect regarding the cause of its glycosides diversity, depending on the sugars moiety attached. This work focuses on four widespread quercetin glycosides—hyperoside, isoquercitrin, quercitrin and rutin—by testing property-tuning capacity of different sugar moieties and thus explain and predict some of their functions in plant-based food. Electron paramagnetic spectra of the semiquinone anion radicals of these glycosides were interpreted in terms of hyperfine coupling constants and linewidths, highlighting a clear link between spin density trends, the identity of the bound sugar, as well as their reactivity corroborated with their modelled structures. Redox potential and lipophilicity were connected to a specific flavonoid-enzyme interaction and correlated with their prooxidant reactivity assessed by oxidation of ferrous hemoglobin. Hyperoside and isoquercitin—galactose and glucose glycosides—exhibit the highest prooxidant reactivity owing to their lowest redox potential and lipophilicity whereas rutin and quercitrin—rutinose and rhamnose glycosides—behave vice versa. The ability of the tested glycosides to undergo HAT or SET-type reactions has also been tested using five different analytical assays, including inhibition of cytochrome ctriggered liposome peroxidation. In most cases, rutin proved to be the most unreactive of all four tested glycosides considering either steric or redox reasons whereas the reactivity hierarchy of the other three glycosides were rather assay dependent.

Authors

• Cezara Zagrean-Tuza,
• Dr Augusitn Mot,
• dr inż. Tomasz Chmiel link open in new tab ,
• Dr Attila Bende,
• Dr Ioan Turcu