Details

Autor(en) / Beteiligte

• Amić, Ana
• Milenković, Dejan
• Marković, Zoran
• Cagardová, Denisa
• Rodríguez-Guerra Pedregal, Jaime
• Dimitrić Marković, Jasmina M.

Titel

Impact of the phenolic O–H vs. C-ring C–H bond cleavage on the antioxidant potency of dihydrokaempferol

Ist Teil von

• New journal of chemistry, 2021-05, Vol.45 (18), p.7977-7986

Ort / Verlag

Cambridge: Royal Society of Chemistry

Erscheinungsjahr

2021

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Kinetics and thermodynamics of the phenolic O–H and the C-ring C–H bond breaking in dihydrokaempferol, a natural flavonoid compound, was investigated using a density functional based approach. The rate constants calculated using the variational transition state theory with multidimensional tunneling corrections indicate 4′-OH phenolic hydrogen as operative in the inactivation of a hydroperoxyl radical (˙OOH). The proton coupled electron transfer (PCET) mechanism appears as preferred in O–H bond breaking by ˙OOH, while the hydrogen atom transfer (HAT) mechanism is involved in the C–H bond cleavage. Comparison of the antioxidant potency of dihydrokaempferol vs. kaempferol proves the superiority of the latter and the negligible role of the C-ring hydrogens of dihydrokaempferol in radical scavenging. The obtained results confirm the traditional view that O–H groups of polyphenols are responsible for radical inactivation contrary to recent proposals that the aliphatic C-ring hydrogens also contribute to this activity.