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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Improvement of Pro-Oxidant Capacity of Protocatechuic Acid by Esterification

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Zeraik, Maria Luiza [1, 2] ; Petronio, Maicon S. [3] ; Coelho, Dyovani [4] ; Regasini, Luis Octavio [2] ; Silva, Dulce H. S. [2] ; da Fonseca, Luiz Marcos [3] ; Machado, Sergio A. S. [4] ; Bolzani, Vanderlan S. [2] ; Ximenes, Valdecir F. [1]
Total Authors: 9
[1] Sao Paulo State Univ, UNESP, Fac Sci, Dept Chem, Sao Paulo - Brazil
[2] Sao Paulo State Univ, UNESP, Nuclei Bioassays Ecophysiol & Biosynth Nat Prod N, Dept Organ Chem, Inst Chem, Sao Paulo - Brazil
[3] Sao Paulo State Univ, UNESP, Sch Pharmaceut Sci, Dept Clin Anal, Sao Paulo - Brazil
[4] Univ Sao Paulo, Inst Chem Sao Carlos, Sao Carlos, SP - Brazil
Total Affiliations: 4
Document type: Journal article
Source: PLoS One; v. 9, n. 10 OCT 23 2014.
Web of Science Citations: 9

Pro-oxidant effects of phenolic compounds are usually correlated to the one-electron redox potential of the phenoxyl radicals. Here we demonstrated that, besides their oxidizability, hydrophobicity can also be a decisive factor. We found that esterification of protocatechuic acid (P0) provoked a profound influence in its pro-oxidant capacity. The esters bearing alkyl chains containing two (P2), four (P4) and seven (P7) carbons, but not the acid precursor (P0), were able to exacerbate the oxidation of trolox, alpha-tocopherol and rifampicin. This effect was also dependent on the catechol moiety, since neither gallic acid nor butyl gallate showed any pro-oxidant effects. A comparison was also made with apocynin, which is well-characterized regarding its pro-oxidant properties. P7 was more efficient than apocynin regarding co-oxidation of trolox. However, P7 was not able to co-oxidize glutathione and NADH, which are targets of the apocynin radical. A correlation was found between pro-oxidant capacity and the stability of the radicals, as suggested by the intensity of the peak current in the differential pulse voltammetry experiments. In conclusion, taking into account that hydroquinone and related moieties are frequently found in biomolecules and quinone-based chemotherapeutics, our demonstration that esters of protocatechuic acid are specific and potent co-catalysts in their oxidations may be very relevant as a pathway to exacerbate redox cycling reactions, which are usually involved in their biological and pharmacological mechanisms of action. (AU)

FAPESP's process: 11/03017-6 - Natural products from plants of Cerrado and Atlantic Forest, potential models and useful for identifying prototypes with oxidizing action on neutrophils and myeloperoxidase (MPO) enzyme
Grantee:Maria Luiza Zeraik
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 13/08784-0 - Kinetic studies of reactions mediated by oxidants produced by neutrophils: mechanism of deleterious action and development of enzyme inhibitors
Grantee:Valdecir Farias Ximenes
Support type: Regular Research Grants
FAPESP's process: 13/07600-3 - CIBFar - Center for Innovation in Biodiversity and Drug Discovery
Grantee:Glaucius Oliva
Support type: Research Grants - Research, Innovation and Dissemination Centers - RIDC