Reaction kinetics have been theoretically examined to ascertain the potency of quercetin (
Q) and flavonoid catecholic metabolites
1–
5 in the inactivation of HOO
•, CH
3OO
•, and O
2•− under physiological conditions. In lipidic
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Reaction kinetics have been theoretically examined to ascertain the potency of quercetin (
Q) and flavonoid catecholic metabolites
1–
5 in the inactivation of HOO
•, CH
3OO
•, and O
2•− under physiological conditions. In lipidic media, the
rate constants for the proton-coupled electron transfer (PCET) mechanism indicate the catecholic moiety of
Q and
1–
5 as the most important in HOO
• and CH
3OO
• scavenging. 5-(3,4-Dihydroxyphenyl)-γ-valerolactone (
1) and alphitonin (
5) are the most potent scavengers of HOO
• and CH
3OO
•, respectively. The
rate constants, representing actual behavior in aqueous media, reveal
Q as more potent in the inactivation of HOO
• and CH
3OO
• via single electron transfer (SET). SET from 3-O
− phenoxide anion of
Q, a structural motif absent in
1–
5, represents the most contributing reaction path to overall activity. All studied polyphenolics have a potency of O
2•− inactivation via a concerted two-proton–coupled electron transfer (2PCET) mechanism. The obtained results indicate that metabolites with notable radical scavenging potency, and more bioavailability than ingested flavonoids, may contribute to human health-promoting effects ascribed to parent molecules.
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