A DFT Study on the Kinetics of HOO^•, CH₃OO^•, and O₂^•− Scavenging by Quercetin and Flavonoid Catecholic Metabolites

• Main Authors: Ana Amić (Author), Denisa Mastiľák Cagardová (Author)
• Format: Book
• Published: MDPI AG, 2023-05-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

Reaction kinetics have been theoretically examined to ascertain the potency of quercetin (<b>Q</b>) and flavonoid catecholic metabolites <b>1</b>-<b>5</b> in the inactivation of HOO^•, CH₃OO^•, and O₂^•− under physiological conditions. In lipidic media, the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mi>k</mi><mrow><mi>overall</mi></mrow><mrow><mi>TST</mi><mo>/</mo><mi>Eck</mi></mrow></msubsup></mrow></semantics></math></inline-formula> rate constants for the proton-coupled electron transfer (PCET) mechanism indicate the catecholic moiety of <b>Q</b> and <b>1</b>-<b>5</b> as the most important in HOO^• and CH₃OO^• scavenging. 5-(3,4-Dihydroxyphenyl)-γ-valerolactone (<b>1</b>) and alphitonin (<b>5</b>) are the most potent scavengers of HOO^• and CH₃OO^•, respectively. The <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mi>k</mi><mrow><mrow><mi>overall</mi></mrow></mrow><mrow><mi>Mf</mi></mrow></msubsup></mrow></semantics></math></inline-formula> rate constants, representing actual behavior in aqueous media, reveal <b>Q</b> as more potent in the inactivation of HOO^• and CH₃OO^• via single electron transfer (SET). SET from 3-O⁻ phenoxide anion of <b>Q</b>, a structural motif absent in <b>1</b>-<b>5</b>, represents the most contributing reaction path to overall activity. All studied polyphenolics have a potency of O₂^•− 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.

Item Description

10.3390/antiox12061154
2076-3921