title: Antioxidant profile of dihydroxy- and trihydroxyphenolic acids--a structure-activity relationship study.
abstract: Eight structurally similar dihydroxy and trihydroxyphenolic acids (protocatechuic acid, 3,4-dihydroxyphenylacetic acid, hydrocaffeic acid, caffeic acid, gallic acid, 3,4,5-trihydroxyphenylacetic acid, 3-(3,4,5-trihydroxyphenyl)propanoic acid and 3-(3,4,5-trihydroxyphenyl)propenoic acid) were examined for their total antioxidant capacity (TAC). Furthermore, their ability to scavenge peroxyl radicals, generated by AAPH in liposomes, was determined. The antioxidant/pro-oxidant activity of the compounds was screened using the 2'-deoxyguanosine assay. All compounds behave as radical scavengers, with 3,4,5-trihydroxyphenylacetic acid being the most potent. Nevertheless, in the lipid peroxidation assay an inverse ranking order was observed, 3,4-dihydroxyphenylacetic acid being the most effective compound. All the dihydroxylated compounds showed a pro-oxidant behaviour leading to an increase of 50% in 8-OH-dG induction. From the structure-antioxidant activity relationship studies performed it may be concluded that the number of phenolic groups and the type of the alkyl spacer between the carboxylic acid and the aromatic ring strongly influence the antioxidant activity.
authors.affiliation: REQUIMTE, Departamento de Química-Física, Universidade do Porto, Faculdade de Farmácia, Porto, Portugal.
authors.forename: Christophe
authors.initials: C
authors.lastname: Siquet
authors.forename: Fátima
authors.initials: F
authors.lastname: Paiva-Martins
authors.forename: José L F C
authors.initials: JL
authors.lastname: Lima
authors.forename: Salette
authors.initials: S
authors.lastname: Reis
authors.forename: Fernanda
authors.initials: F
authors.lastname: Borges
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D004249:DNA Damage; D062385:Hydroxybenzoates / Q000737:chemistry*; D013329:Structure-Activity Relationship
chemical_list: D000975:Antioxidants; D062385:Hydroxybenzoates; C017616:phenolic acid