TOXICIDADE, CITOTOXICIDADE E GENOTOXICIDADE DE COMPOSTOS HALOGENADOS PRODUZIDOS POR SPHAEROCAVUM (CIANOBACTÉRIA)

Joice Mara Zanini, Janaína Rigonato, Marli Fátima Fiore, Maria Estela
Silva-Stenico

Centro de Energia Nuclear na Agricultura, Piracicaba-SP; e-mail: [e-mail]

Summary

Resultados

Among the large number of biologically active peptides, the halogenated compounds aeruginosin and cyanopeptolin (protease inhibitors) are well documented in several cyanobacteria. Cyanobacteria have an enormous number of bioactive compounds, most lacking toxicological data. Protease inhibitors produced by cyanobacteria comprise a class of linear and cyclic peptide produced mainly by Microcystis sp. The functions of protease inhibitors has been well-documented, but information on their genotoxic effects is relatively scarce. In this study, the toxicity, citotoxicity and genotoxicity of methanolic extracts of Sphaerocavum brasiliense
CCIBt3094, containing high levels of aeruginosins and cyanopeptolins were evaluated. Five endpoints, using plant assays in Allium cepa were applied: rootlet growth inhibition, chromosomal aberrations, mitotic divisions, and micronucleus assays. Morphological changes such as tumor formation and meristem necrosis were not observed after treatment.
However, the extract inhibited the growth of roots in both 24 and 48h compared to control. This has been reflected by the mitotic index, where it was also observed the decrease after the periods of treatment. The mitotic phase which was more influenced was the metaphase, where in both treatments (acute and chronic) caused a decrease in the number of cells at this stage of mitosis, and after chronic treatment was observed to decrease in anaphase cells. However, chromosomal changes were not observed.

Toxicidade (a) e citoxicidade (b) causada pela ação do extrato etanólico de S. brasiliense CCIBt
3094. Barra azul controle negativo, vermelha extrato S. brasiliense CCIBt 3094. *significativo para Teste T.
Indice de fases após 24 e 48h de tratamento com extrato de
S.