title: Estimation of scavenging activity of phenolic compounds using the ABTS(*+) assay.
abstract: Observations on the applicability of the ABTS(*+) assay to define structure-activity relationships (SARs) among phenols (AH) were based on experimental data and theoretical calculations. All AH examined (hydroxycinnamic derivatives, simple polyphenols, polyhydroxybenzoates, and flavonoids) were found to be active toward ABTS(*+). Moreover, known weak radical scavengers (i.e., coumaric and isoferulic acids) were found to be efficient or comparatively active to caffeic or rosmarinic acids in contradiction to the AH classification based on 1,1-diphenyl-2-picrylhydrazyl (DPPH) data or the bond dissociation enthalpy values. This behavior was observed both in ethanol and in buffered (pH 7.4) environment. Resorcinol and phloroglucin were found to be more active than catechol and hydroquinone, whereas, among polyhydroxybenzoates, 2,4-dihydroxybenzoic acid was the least active, in line with the DPPH and theoretical data. Therefore, it can be argued that the ABTS(*+) assay may give an indication for the presence of antioxidants in a certain system but SARs cannot be readily inferred.
authors.affiliation: Laboratory of Food Chemistry and Technology, School of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Nenadis
authors.forename: Lan-Fen
authors.initials: LF
authors.lastname: Wang
authors.forename: Maria
authors.initials: M
authors.lastname: Tsimidou
authors.forename: Hong-Yu
authors.initials: HY
authors.lastname: Zhang
mesh_terms: D052160:Benzothiazoles; D001713:Biphenyl Compounds; D002934:Cinnamates / Q000737:chemistry; D005419:Flavonoids / Q000737:chemistry; D016166:Free Radical Scavengers / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry*; D010851:Picrates / Q000737:chemistry; D059808:Polyphenols; D013053:Spectrophotometry; D013329:Structure-Activity Relationship; D013451:Sulfonic Acids / Q000737:chemistry*
chemical_list: D052160:Benzothiazoles; D001713:Biphenyl Compounds; D002934:Cinnamates; D005419:Flavonoids; D016166:Free Radical Scavengers; D010636:Phenols; D010851:Picrates; D059808:Polyphenols; D013451:Sulfonic Acids; C029010:cinnamic acid; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; C004931:1,1-diphenyl-2-picrylhydrazyl