Genotoxic evaluation of the effect of Thuya occidentalys tinctures

Three tinctures samples from extracts of the popular medicinal plant Thuya occidentalis were tested in vitro through two short term tests for measuring the activity of genotoxic chemicals. Using the Salmonella/mammalian-microsome (Mutatest) assay and the SOS-chromotest (induction of beta-galactosidase in Escherichia coli), none of the extract was effective in inducing mutagenesis or beta-galactosidase synthesis (as an indicator of general and early sign of DNA damage), even with metabolization

Absence of mutagenicity of Potomorphe umbellata and Potomorphe peltata in the Salmonella/mammalian-microsome mutagenicity assay

The development of short term tests for measuring the mutagenic activity of genotoxic chemicals has been helpful in increasing security. Natural products from the flora are largely used in popular medicine. Using the Salmonella/mammalian-microsome assay, we investigated the genetic toxicity of two plant species popularly used in malaria treatment, Pothomorphe umbrellata and Pothomorphe peltata. The data show the absence of genetic toxicity for both plant species

A quantative study for starvation-induced photoresistance in E. coli.

Curvas de sobrevivencia a radiacao ultravioleta de culturas de diversas cepas de E. coli K 12, proficientes ou nao em sistemas de reparacao, foram obtidas apos carenciamento em glicose e em fatores indispensaveis a multiplicacao bacteriana. Estas curvas foram matematicamente ajustadas a modelo previamente descrito, o que permitiu estabelecer parametro para expressar o aumento de fotorresistencia induzida pelo carenciamento (SIRE). Os resultados obtidos reforcam a hipotese de estar o SIRE relacionado com o mecanismo de reparacao por excisao