Abstract
During the scavenging of free radicals flavonoids are oxidized to electrophilic quinones. Glutathione (GSH) can trap these quinones, thereby forming GSH-flavonoid adducts. The aim of this study was to compare the stability of the GSH-flavonoid adduct of 7-mono-O-(beta-hydroxyethyl)rutoside (monoHER) with that of quercetin. It was found that GSH-quercetin reacts with the thiol N-acetyl-l-cysteine (NAC) to form NAC-quercetin, whereas GSH-monoHER does not react with NAC. In addition, the adduct of the monoHER quinone with the dithiol dithiothreitol (DTT) is relatively stable, whereas the DTT-quercetin adduct is readily converted into quercetin and DTT disulfide. These differences in reactivity of the thiol-flavonoid adducts demonstrate that GSH-monoHER is much more stable than GSH-quercetin. This difference in reactivity was corroborated by molecular quantum chemical calculations. Thus, although both flavonoid quinones are rapidly scavenged by GSH, the advantage of monoHER is that it forms a stable conjugate with GSH, thereby preventing a possible spread of toxicity. These findings demonstrate that even structurally comparable flavonoids behave differently, which will be reflected in the biological effects of these flavonoids.
Original language | English |
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Pages (from-to) | 2118-2123 |
Number of pages | 6 |
Journal | Free Radical Biology and Medicine |
Volume | 51 |
Issue number | 11 |
DOIs | |
Publication status | Published - 1 Dec 2011 |
Keywords
- 7-Mono-O-(beta-hydroxyethyl)rutoside
- MonoHER
- Flavonoid
- Antioxidant
- Quercetin
- Glutathione
- Thiols
- Free radicals
- DOXORUBICIN-INDUCED CARDIOTOXICITY
- MONOHYDROXYETHYLRUTOSIDE
- RADICALS
- ANTIOXIDANT
- SEMIQUINONE
- PROOXIDANT
- OXIDATION
- TOXICITY
- THIOLS
- DAMAGE