RESUMO
Chlorpyrifos (CP) is one of the organophosphate insecticides most used worldwide today. Although the main target organ for CP is the nervous system triggering predominantly neurotoxic effects, it has suggested other mechanisms of action as cytotoxicity and endocrine disruption. The risk posed by the pesticide metabolites on non-target organisms is increasingly recognized by regulatory agencies and natural resource managers. In the present study, cytotoxicity and estrogenic activity of CP, and its principal metabolite 3,5,6-trichloro-2-pyridinol (TCP) have been evaluated by in vitro assays, using two mammalian cell lines (HEK293 and N2a), and a recombinant yeast. Results indicate that TCP is more toxic than CP for the two cell lines assayed, being N2a cells more sensitive to both compounds. Both compounds show a similar estrogenic activity being between 2500 and 3000 times less estrogenic than 17ß-estradiol. In order to find new toxicity measurement models, yeasts isolated from marine sediments containing CP residues have been tested against CP and TCP by cell viability assay. Of the 12 yeast strains tested, 6 of them showed certain sensitivity, and a concentration-dependent response to the tested compounds, so they could be considered as future models for toxicity tests, although further investigations and proves are necessary.
Assuntos
Clorpirifos , Inseticidas , Piridonas/metabolismo , Animais , Organismos Aquáticos/efeitos dos fármacos , Clorpirifos/toxicidade , Células HEK293 , Humanos , Inseticidas/toxicidade , Piridonas/toxicidade , Testes de Toxicidade , Leveduras/efeitos dos fármacosRESUMO
Pirfenidone is a non-steroidal antifibrotic compound that has been proposed in clinical protocols and experimental studies as a pharmacological treatment for fibroproliferative diseases. The objective of this study was to determine the genotoxicity or cytotoxicity of three doses of pirfenidone using the micronuclei test in peripheral blood erythrocytes of rodent models. Pirfenidone was administered orally to Balb-C mice for 3 days, and also was administered topically to hairless Sprague Dawley rats during the final stage of gestation. Mice were sampled every 24 h over the course of 6 days; pregnant rats were sampled every 24 h during the last 6 days of gestation, and pups were sampled at birth. Blood smears were analyzed and the frequencies of micronucleated erythrocytes (MNEs), micronucleated polychromatic erythrocytes (MNPCEs), and the proportion of polychromatic erythrocytes (PCEs), were recorded in samples from mice, pregnant rats and rat neonates. Increases in MN frequencies (p<0.03) were noted only in the positive control groups. No genotoxic effects or decreased PCE values were observed neither in newborn rats transplacentally exposed to pirfenidone, or in two adult rodent models when pirfenidone was administered orally or topically.
Assuntos
Anti-Inflamatórios não Esteroides/toxicidade , Eritrócitos/efeitos dos fármacos , Testes para Micronúcleos , Mutagênicos/toxicidade , Piridonas/toxicidade , Animais , Eritrócitos/ultraestrutura , Feminino , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Gravidez , Ratos , Ratos Sprague-DawleyRESUMO
The in vitro effects of flurochloridone (FLC) and its formulations Twin Gold Pack® (25% a.i.) and Rainbow® (25% a.i.) were evaluated on Chinese hamster ovary (CHO-K1) cells by genotoxicity [sister chromatid exchange (SCE)] and cytotoxicity [cell-cycle progression, proliferative rate index (PRI), mitotic index (MI), MTT, and neutral red] end points. Cells were treated for 24h within the 0.25-15µg/ml concentration range. FLC and Twin Pack Gold® induced a significant and equivalent increase in SCEs regardless of the concentration. Rainbow®-induced SCEs at concentrations higher than 2.5µg/ml; however, the increases were always lower than those induced by FLC and Twin Pack Gold®. For all compounds, the PRI decreased as a function of the concentration titrated into cultures. Whereas only the highest FLC and Twin Pack Gold® concentrations induced a significant reduction of the MI, all tested Rainbow® concentrations induced MI inhibition. Overall, the results demonstrated that although all compounds were not able to reduce the lysosomal activity, the mitochondrial activity was diminished when the highest concentrations were employed. These observations represent the first study analyzing the genotoxic and cytotoxic effects exerted by FLC and two formulated products on mammalian cells in vitro, at least on CHO-K1 cells.
Assuntos
Herbicidas/toxicidade , Mutagênicos/toxicidade , Piridonas/toxicidade , Pirrolidinonas/toxicidade , Animais , Células CHO , Ciclo Celular/efeitos dos fármacos , Cricetinae , Cricetulus , Índice Mitótico , Troca de Cromátide IrmãRESUMO
The focus of this study was the identification of compounds from plant extracts for use in crop protection. This paper reports on the toxic activity of fractions of leaf extracts of Ricinus communis L (Euphorbiaceae) and isolated active compounds in the leaf-cutting ant Atta sexdens rubropilosa Forel and its symbiotic fungus Leucoagaricus gongylophorus (Singer) Möller. The main compounds responsible for activity against the fungus and ant in leaf extracts of R communis were found to be fatty acids for the former and ricinine for the ants.