title: Water extracts of Brassica oleracea var. costata potentiate paraquat toxicity to rat hepatocytes in vitro.
abstract: Tronchuda cabbage extracts have been proven to have antioxidant potential against various oxidative species in cell free systems, though its antioxidant potential in cellular models remained to be demonstrated. In the present study, we used primary cultures of rat hepatocytes for the cellular assay system and paraquat PQ exposure as a pro-oxidant model agent, to test whether tronchuda cabbage hydrolysed water extracts provide protective or aggravating effects towards PQ-induced oxidative stress and cell death. For this purpose cellular parameters related to oxidative stress were measured, namely the generation of superoxide anion, glutathione oxidation, lipid peroxidation, intracellular ATP levels, activation of nuclear factor-kappaB (NF-kappaB), activity of antioxidant enzymes, and cell death. The obtained results demonstrated that the studied hydrolysed water extracts of tronchuda cabbage, especially rich in kaempferol (84%) and other polyphenols, namely hydroxycinnamic acids and traces of quercetin, can potentiate the toxicity of PQ in primary cultures of rat hepatocytes. These results highlight that prospective antioxidant effects of plant extracts, observed in vitro, using non-cellular systems, are not always confirmed in cellular models, in which the concentrations required to scavenge pro-oxidant species may be highly detrimental to the cells.
authors.affiliation: REQUIMTE, Toxicology Department, Faculty of Pharmacy, University of Porto, 4099-030 Porto, Portugal. csousa@ff.up.pt
authors.forename: C
authors.initials: C
authors.lastname: Sousa
authors.forename: H
authors.initials: H
authors.lastname: Pontes
authors.forename: H
authors.initials: H
authors.lastname: Carmo
authors.forename: R J
authors.initials: RJ
authors.lastname: Dinis-Oliveira
authors.forename: P
authors.initials: P
authors.lastname: Valentão
authors.forename: P B
authors.initials: PB
authors.lastname: Andrade
authors.forename: F
authors.initials: F
authors.lastname: Remião
authors.forename: M L
authors.initials: ML
authors.lastname: Bastos
authors.forename: F
authors.initials: F
authors.lastname: Carvalho
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000302:isolation & purification / Q000633:toxicity; D001937:Brassica / Q000737:chemistry*; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D005419:Flavonoids / Q000302:isolation & purification / Q000633:toxicity; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects*; D010269:Paraquat / Q000633:toxicity*; D010636:Phenols / Q000302:isolation & purification / Q000633:toxicity; D010936:Plant Extracts / Q000633:toxicity*; D059808:Polyphenols; D051381:Rats; D017208:Rats, Wistar; D014867:Water / Q000737:chemistry
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D059808:Polyphenols; D014867:Water; D010269:Paraquat