Abstract This study aimed to evaluate DNA damage in animal and plant cells exposed to water from the Água Boa stream (Dourados, Mato Grosso do Sul, Brazil) by using bioassays, and to identify the chemical compounds in the water to determine the water quality in the area. Through the cytotoxicity bioassay with Allium cepa, using micronucleus test, and comet assay, using Astyanax altiparanae fish, the results indicated that biological samples were genetically altered. Micronuclei were observed in erythrocytes of A. altiparanae after exposure to water from locations close to industrial waste discharge. The highest DNA damage observed with the comet assay in fish occurred with the exposure to water from locations where the presence of metals (Cu, Pb, Cd, Ni) was high, indicating the possibility of genotoxic effects of these compounds. Thus, these results reinforce the importance of conducting genotoxicity tests for developing management plans to improve water quality, and indicate the need for waste management before domestic and industrial effluents are released into the rivers and streams.

Abstract Brazilian green propolis is a resinous substance prepared by bees from parts of the plant Baccharis dracunculifolia. As it possess several biological properties, this work assessed the cytotoxic/anticytotoxic, genotoxic/antigenotoxic and mutagenic/antimutagenic potential of ethanolic extracts of Brazilian green propolis (EEGP) and of B. dracunculifolia (EEBD), by means of the Allium cepa test system. The effects were evaluated by assessing the chromosomal aberrations (CA) and micronuclei (MN) frequencies on meristematic and F1 generation cells from onion roots. Chemical analyses performed with the extracts showed differences in flavonoid quality and quantity. No genotoxic or mutagenic potential was detected, and both extracts were capable of inhibiting cellular damage caused by methyl methanesulfonate (MMS) treatment, reducing the frequencies of CA and MN. By these data, we can infer that, independent of their flavonoid content, the extracts presented a protective effect in A. cepa cells against the clastogenicity of MMS.

Jatropha gossypiifolia L. (Euphorbiaceae), popularly known as cotton-leaf physicnut, is a milky shrub notable for its medicinal properties. The present study aimed to evaluate the toxic, cytotoxic and genotoxic effects of the latex of J. gossypiifolia, using Allium cepa L. as test system. Seeds of A. cepa were exposed to five concentrations of the latex (1.25; 2.5; 5; 10 and 20 mL/L) in order to evaluate parameters of toxicity (evaluation of root growth), cytotoxicity (mitotic index frequency) and genotoxicity (frequency of chromosome alterations). The latex showed a significant decrease in root mean growth value as well as mitotic index for the tested concentrations, except for 1.25 mL/L, when compared to results from the negative control. The 1.25, 2.5 and 5 mL/L concentrations induced significant chromo-some adherences, C-metaphases and/or chromosome bridges, as genotoxic effects. The significant frequency of chromosome bridges also indicated mutagenic potential for chromosomes of J. gossypiifolia as discussed in the paper. Considering that the latex is used in popular therapies, and that the test system A. cepa presents good correlation with tests carried out in mammals, it can be pointed out that its use for medicinal purposes may be harmful to human health especially if ingested.

Karyotypes of six species of the genus Stevia from Southern Brazil were studied, utilizing root tip metaphases. All species were diploid with 2n = 22 chromosomes. It was possible to identify each species by chromosome morphology. The basic chromosome number for Brazilian species of Stevia is X = 11. This number is also found in almost all South American species. We suggest that in Stevia there is an evolutionary trend toward chromosomal rearrangement, caused mainly by pericentric inversions. It was found that, in addition to aneuploidy and polyploidy, chromosomal rearrangements are common in the tribe Eupatorieae.