title: High-throughput assay comparison and standardization for metal chelating capacity screening: A proposal and application.
abstract: Aiming to standardize the experimental protocols to assess the ability to chelate Fe(2+) and Cu(2+) using 96-well microplates, we analyzed Brazilian coffees (n=20) as a study-case in relation to their antioxidant activity using conventional methods (DPPH and FRAP assays) and correlated the results with the total phenolic content (TPC) using bivariate and multivariate statistical approaches. Complementarily, we assessed the repeatability, reproducibility, recovery, and linearity of both methods. Data showed that the proposed assays presented a good repeatability and reproducibility (<7% RSD) and mean recovery values of 96.66% and 98.91% for the iron and copper assays, respectively. Both methods were linear in the range of 0-100mg EDTA equivalents/L. Cu(2+)-chelating ability was significantly correlated to FRAP, DPPH, and TPC, while sparse (p<0.05) correlations were obtained with Fe(2+)-chelating ability. Overall, both micro assays can be used to assess the ability of plant-based extracts to chelate Fe(2+) and Cu(2+)in vitro.
authors: Food Science and Technology Graduate Program, State University of Ponta Grossa, Av. Carlos Cavalcanti, 4748, 84030-900, Uvaranas Campus, Ponta Grossa, PR, Brazil.
authors: Jânio Sousa
authors: JS
authors: Santos
authors: Department of Food Engineering, State University of Ponta Grossa, Av. Carlos Cavalcanti, 4748, 84030-900, Uvaranas Campus, Ponta Grossa, PR, Brazil.
authors: Vitor Rafael
authors: VR
authors: Alvarenga Brizola
authors: Food Science and Technology Graduate Program, State University of Ponta Grossa, Av. Carlos Cavalcanti, 4748, 84030-900, Uvaranas Campus, Ponta Grossa, PR, Brazil; Department of Food Engineering, State University of Ponta Grossa, Av. Carlos Cavalcanti, 4748, 84030-900, Uvaranas Campus, Ponta Grossa, PR, Brazil. Electronic address: dgranato@uepg.br.
authors: Daniel
authors: D
authors: Granato
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D001938:Brazil; D002614:Chelating Agents / Q000737:chemistry; D040503:Coffea / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D057166:High-Throughput Screening Assays / Q000379:methods*; D007501:Iron / Q000737:chemistry*; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry; D015203:Reproducibility of Results
chemical_list: D000975:Antioxidants; D002614:Chelating Agents; D010636:Phenols; D003300:Copper; D007501:Iron
keywords: Antioxidant activity; Iron binding; Metal chelator; Method validation; Phenolic compounds; Principal component analysis