title: Flavonoids electrochemical detection in fruit extracts and total antioxidant capacity evaluation.
abstract: Phenolic compounds detection in fruit extracts from: açai, bacuri, buriti, blackberry, black mulberry, blueberry, juçara, physalis, raspberry, and tamarillo, have been performed by reverse-phase high performance liquid chromatography with electrochemical detection (RP-HPLC-EC), using two detectors in series: a wall-jet detector flow cell with a glassy carbon electrode, and a thin-layer flow cell detector with a boron doped diamond electrode. This methodology, in gradient elution mode, was successfully used to detect seventeen phenolic compounds in the fruit extracts. The total antioxidant capacity of the fruit extracts by the electrochemical quantitative index (EI) and the method of capture of diphenilpicrilhydrazil (DPPH(●)) free radical "efficient concentration" (EC50), was evaluated. A very good correlation between EI and EC50 assays has been obtained, the fruit with the highest total antioxidant capacity being blackberry, while physalis exhibited the lowest antioxidant power.
authors.affiliation: Chemistry Department, University of Coimbra, 3004-535 Coimbra, Portugal.
authors.forename: Sara M C
authors.initials: SM
authors.lastname: Gomes
authors.affiliation: Chemistry Department, University of Coimbra, 3004-535 Coimbra, Portugal.
authors.forename: Mariana-Emilia
authors.initials: ME
authors.lastname: Ghica
authors.affiliation: Chemistry Department, University of Coimbra, 3004-535 Coimbra, Portugal; Departamento de Química, Universidade Federal do Maranhão, São Luís, Maranhão CEP: 65080-040, Brazil.
authors.forename: Isaide Araujo
authors.initials: IA
authors.lastname: Rodrigues
authors.affiliation: Chemistry Department, University of Coimbra, 3004-535 Coimbra, Portugal; Faculdade de Farmácia, Universidade Federal de Goiânia, Goiânia CEP: 74605-170, Brazil.
authors.forename: Eric
authors.initials: E
authors.lastname: de Souza Gil
authors.affiliation: Chemistry Department, University of Coimbra, 3004-535 Coimbra, Portugal. Electronic address: brett@ci.uc.pt.
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Oliveira-Brett
mesh_terms: D000975:Antioxidants; D002851:Chromatography, High Pressure Liquid; D055664:Electrochemical Techniques; D005419:Flavonoids; D005638:Fruit; D010636:Phenols; D010936:Plant Extracts
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts
keywords: Boron doped diamond electrode; EC(50) and EI assays; Glassy carbon electrode; Phenolic compounds; RP-HPLC-EC