title: Automated cytochrome c oxidase bioassay developed for ionic liquids' toxicity assessment.
abstract: A fully automated cytochrome c oxidase assay resorting to sequential injection analysis (SIA) was developed for the first time and implemented to evaluate potential toxic compounds. The bioassay was validated by evaluation of 15 ionic liquids (ILs) with distinct cationic head groups, alkyl side chains and anions. The assay was based on cytochrome c oxidase activity reduction in presence of tested compounds and quantification of inhibitor concentration required to cause 50% of enzyme activity inhibition (EC50). The obtained results demonstrated that enzyme activity was considerably inhibited by BF4 anion and ILs incorporating non-aromatic pyrrolidinium and tetrabutylphosphonium cation cores. Emim [Ac] and chol [Ac], on contrary, presented the higher EC50 values among the ILs tested. The developed automated SIA methodology is a simple and robust high-throughput screening bioassay and exhibited good repeatability in all the tested conditions (rsd<3.7%, n=10). Therefore, it is expected that due to its simplicity and low cost, the developed approach can be used as alternative to traditional screening assays for evaluation of ILs toxicity and identification of possible toxicophore structures. Additionally, the results presented in this study provide further information about ILs toxicity.
authors.affiliation: LAQV, Requimte, Departamento de Ciências Químicas, Laboratório de Química Aplicada, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, N° 228, 4050-313 Porto, Portugal.
authors.forename: Susana P F
authors.initials: SP
authors.lastname: Costa
authors.affiliation: LAQV, Requimte, Departamento de Ciências Químicas, Laboratório de Química Aplicada, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, N° 228, 4050-313 Porto, Portugal.
authors.forename: Bárbara S F
authors.initials: BS
authors.lastname: Martins
authors.affiliation: LAQV, Requimte, Departamento de Ciências Químicas, Laboratório de Química Aplicada, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, N° 228, 4050-313 Porto, Portugal. Electronic address: ppinto@ff.up.pt.
authors.forename: Paula C A G
authors.initials: PC
authors.lastname: Pinto
authors.affiliation: LAQV, Requimte, Departamento de Ciências Químicas, Laboratório de Química Aplicada, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, N° 228, 4050-313 Porto, Portugal. Electronic address: lsaraiva@ff.up.pt.
authors.forename: M Lúcia M F S
authors.initials: ML
authors.lastname: Saraiva
mesh_terms: D001681:Biological Assay; D003576:Electron Transport Complex IV / Q000037:antagonists & inhibitors*; D057166:High-Throughput Screening Assays; D052578:Ionic Liquids / Q000633:toxicity*
chemical_list: D052578:Ionic Liquids; D003576:Electron Transport Complex IV
keywords: Cytochrome c oxidase; Ionic liquids; SIA; Toxicity screening