RESUMO
The genotoxicity of river water and sediment including interstitial water was evaluated by microscreen phage-induction and Salmonella/microsome assays. Different processes used to fractionate the sediment sample were compared using solvents with different polarities. The results obtained for mutagenic activity using the Salmonella/microsome test were negative in the water and interstitial water samples analysed using the direct concentration method. The responses in the microscreen phage-induction assay showed the presence of genotoxic or indicative genotoxic activity for at least one water sample of each site analysed using the same concentration method. Similar results were obtained for interstitial water samples, i.e. absence of mutagenic activity in the Salmonella/microsome test and presence of genotoxic activity in the microscreen phage-induction assay. Metal contamination, as evidenced by the concentrations in stream sediments, may also help explain some of these genotoxic results. Stream sediment organic extracts showed frameshift mutagenic activity in the ether extract detected by Salmonella/microsome assay. The concentrates evaluated by microscreen phage-induction assay identified the action of organic compounds in the non-polar, medium polar and polar fractions. Thus, the microscreen phage-induction assay has proven to be a more appropriate methodology than the Salmonella/microsome test to analyse multiple pollutants in this ecosystem where both organic compounds and heavy metals are present.
Assuntos
Bacteriófago lambda/fisiologia , DNA Bacteriano/efeitos dos fármacos , Metais Pesados/toxicidade , Salmonella typhimurium/efeitos dos fármacos , Ativação Viral/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Poluição Química da Água/análise , Animais , Bacteriófago lambda/genética , Biotransformação , Brasil , DNA Bacteriano/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/virologia , Água Doce , Genes Bacterianos/efeitos dos fármacos , Sedimentos Geológicos/química , Resíduos Industriais/análise , Lisogenia , Masculino , Metais Pesados/análise , Metais Pesados/isolamento & purificação , Microssomos Hepáticos/metabolismo , Testes de Mutagenicidade , Ratos , Ratos Sprague-Dawley , Resposta SOS em Genética , Salmonella typhimurium/genética , Solventes , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/isolamento & purificaçãoRESUMO
Aqueous extracts of medicinal plants used in south Brazilian folk medicine (Myrciaria tenella, Smilax campestris, Tripodanthus acutifolius and Cassia corymbosa) were screened for the presence of mutagenic activity in the Salmonella/microsome assay. Signs of an increased mutagenic induction below revertant rates, which is two times the spontaneous yields, were detected for all extracts. The extracts of C. corymbosa showed signs of mutagenic activity in the following strains: TA100 with and without metabolization and TA98 after metabolization. These mutagenic signs were observed in the M. tenella extracts without metabolization. S. campestris and T. acutifolius infusions also showed signs indicative of direct mutagenic activity in the TA98 strain. The positive results may be related to the presence of flavonoids, tannins and anthraquinones in the extracts.