RESUMO
Background: the toxicity of many chemical substances has been studied by many of living organisms used as biological indicators. Higher organisms[laboratory animals] are generally used but the response time may be lengthy. Never the less by exploiting uni cellular organisms, in particulary yeast, it is possible to reduce testing time considerably. In this study, the budding yeast, saccharomyces cerevisiae asimple non-pathogenic eukaryotic organisms, which is easy to cultivate, has been used as experimental model for assaying acute toxicity of chemical substances
Material and Methods: As a experimental study, The first step yeast cells were cultured in broth media and correlation cell of numbers and optical density was determined in 525 nm. Then, yeast cells were cultured in the presence of various concentration of chemical substances and cell density was measured. the proliferation rate determined from the logarithmic growth phase. A dose-response curve was obtained by plotting the relative growth rate versus the chemical concentration which concentrations leading to 50% inhibition of growth[IC50] was determined
Results: the results showed a concentration - dependent cytoxicity effect for saff flower extract [IC50=112[micro]lml-1] and peganum harmala extract [IC50=476[micro]gml-1]. The toxicity effects of dihidropyridine derivatives was studied up to 100 [micro]Mml-1, but no cytotoxic effect was observed
Conclusion: these results were agreement with other cytotoxic tests [i.e, rat, hamster, brin shrimp, and human cell cultures] then this procedure can be used as the first step, for assaying acute toxicity of chemical substances