Peroxynitrite oxidises catechols to o-quinones.
Nitration of phenolic compounds is a well-established mechanism on interaction with peroxynitrite. However, while nitration is the predominant reaction for monophenolic hydroxycinnamates, this does not take place with the catechol-containing hydroxycinnamate, caffeic acid. The aim of the present study was to investigate the mechanism of the chemical interaction of caffeic acid with peroxynitrite and to characterise the products formed. A novel compound was detected and characterised as the o-quinone of caffeic acid based on its reaction with nucleophilic thiol compounds, glutathione and L-cysteine. The same novel product was identified following the oxidation of caffeic acid in alkaline solutions confirming the identity of this species as a caffeic acid oxidation product.
Kerry
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N
Antioxidant Research Centre, Guy's, King's College and St. Thomas's School of Biomedical Sciences, London, UK.
Rice-Evans
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C
D002109:Caffeic Acids / Q000737:chemistry; D002396:Catechols / Q000737:chemistry* / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000737:chemistry; D005978:Glutathione / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007536:Isomerism; D009566:Nitrates / Q000737:chemistry*; D010084:Oxidation-Reduction; D011809:Quinones / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry
D002109:Caffeic Acids; D002396:Catechols; D009566:Nitrates; D011809:Quinones; D013438:Sulfhydryl Compounds; C039642:peroxynitric acid; D005978:Glutathione; D003545:Cysteine; C040048:caffeic acid