Singlet oxygen quenching and the redox properties of hydroxycinnamic acids.
McGarvey, David J
Land, Edward J
Truscott, T G
Rice-Evans, Catherine A
AffiliationDepartment of Chemistry, Keele University, Staffordshire, UK.
MetadataShow full item record
AbstractThe singlet oxygen quenching rate constants (kq) for a range of hydroxycinnamic acids in acetonitrile and D2O solutions were measured using time resolved near infrared phosphorescence in order to establish their antioxidant activity. The magnitude of kq observed depends on both the nature of the substituent groups and solvent polarity. The variations in kq depend on the energy of the hydroxycinnamic acid/molecular oxygen charge transfer states, (O2delta- ...HCAdelta+). In D2O the values of kq range from 4x10(7) M(-1) s(-1) to 4x10(6) M(-1) s(-1) for caffeic acid and o-coumaric acid respectively. In acetonitrile, the charge transfer energy levels are raised and this is reflected in lower singlet oxygen quenching rate constants with a kq value of 5x10(6) M(-1) s(-1) for caffeic acid. The phenoxyl radical spectra derived from the hydroxycinnamic acids were determined using pulse radiolysis of aqueous solutions and the reduction potentials were found to range from 534 to 596 mV. A linear correlation is observed between reduction potential, and hence free energy for electron transfer, and log kq. These correlations suggest a charge transfer mechanism for the quenching of singlet oxygen by the hydroxycinnamic acids.
CitationSinglet oxygen quenching and the redox properties of hydroxycinnamic acids. 1999, 26 (9-10):1202-8 Free Radic. Biol. Med.
JournalFree Radical Biology & Medicine
- Interaction of hydroxycinnamic acid derivatives with the Cl3COO radical: a pulse radiolysis study.
- Authors: Pan JX, Wang WF, Lin WZ, Lu CY, Han ZH, Yao SD, Lin NY
- Issue date: 1999 Mar
- Laser flash photolysis study on antioxidant properties of hydroxycinnamic acid derivatives.
- Authors: Zhu H, Zhao H, Zhang Z, Wang W, Yao S
- Issue date: 2006 May
- Hydroxycinnamic acid antioxidants: an electrochemical overview.
- Authors: Teixeira J, Gaspar A, Garrido EM, Garrido J, Borges F
- Issue date: 2013
- Antioxidant Activity of Foods: Development of Singlet Oxygen Absorption Capacity (SOAC) Assay Method.
- Authors: Mukai K
- Issue date: 2019
- Kinetic study of quenching reactions of singlet oxygen and scavenging reactions of free radicals by alpha-, beta-, gamma- and delta- tocopheramines in ethanol solution and micellar dispersion.
- Authors: Itoh S, Nagaoka S, Mukai K, Ikesu S, Kaneko Y
- Issue date: 1994 Nov