Stryphnodendron adstringens (Mart.) Coville, a medicinal plant that grows in the "cerrados" (a savanna ecosystem) of Brazil, popularly known as "Barbatimão," is an important source of tannins (polyphenols). In Brazil, it is used in industry (mainly as vegetable tanning) and also in traditional medicine for the treatment of various diseases. In the present study, a phytotherapeutic extract from S. adstringens stem bark was evaluated for mutagenic and recombinagenic effects using the wing spot test of Drosophila melanogaster (somatic mutation and recombination test, SMART), and for chromosome damage in germ cells using the Drosophila sex-chromosome loss test (ring-X loss). For SMART, the standard as well as the high bioactivation fly crosses were used; the latter cross is characterized by a high sensitivity to promutagens and procarcinogens. Third-instar larvae from these two crosses were treated for 48 hr with different concentrations (66%, 75%, and 100%) of the phytotherapeutic extract. The wings of the emerging adults were analyzed for the occurrence of different types of mutant spots. No statistically significant differences in spot frequencies between controls and treated series were observed. For the ring-X loss test, adult males were fed with the same concentrations of the extract as in the wing spot test. No statistically significant increases in ring-X losses were observed. The results of our experiments suggest that the phytotherapeutic extract from S. adstringens stem bark is not genotoxic in somatic and germ cells of D. melanogaster.

The wing Somatic Mutation and Recombination Test (SMART) in D. melanogaster was used to study genotoxicity of the medicinal plant Tabebuia impetiginosa. Lapachol (naphthoquinone) and β-lapachone (quinone) are the two main chemical constituents of T. impetiginosa. These compounds have several biological properties. They induce apoptosis by generating oxygen-reactive species, thereby inhibiting topoisomerases (I and II) or inducing other enzymes dependent on NAD(P)H:quinone oxidoreductase 1, thus affecting cell cycle checkpoints. The SMART was used in the standard (ST) version, which has normal levels of cytochrome P450 (CYP) enzymes, to check the direct action of this compound, and in the high bioactivation (HB) version, which has a high constitutive level of CYP enzymes, to check for indirect action in three different T. impetiginosa concentrations (10%, 20% or 40% w/w). It was observed that T. impetiginosa alone did not modify the spontaneous frequencies of mutant spots in either cross. The negative results observed prompted us to study this phytotherapeuticum in association with the reference mutagen doxorubicin (DXR). In co-treated series, T. impetiginosa was toxic in both crosses at higher concentration, whereas in the HB cross, it induced a considerable potentiating effect (from ~24.0 to ~95.0%) on DXR genotoxity. Therefore, further research is needed to determine the possible risks associated with the exposure of living organisms to this complex mixture.

Avaliação do efeito modulador da levedura de cerveja (SAcchAromyceS cereviSiAe m.) sobre a genotoxicidade induzida pela doxorrubicina em DroSophilA melAnogASter victor borges rezende

A Mandevilla velutina crude extract was investigated using the mouse micronucleus test (MNT) and the Drosophila melanogaster somatic mutation and recombination test (SMART) using standard (ST) and high bioactivation (HB) crosses. The MNT used 10 mg, 20 mg or 40 mg per 100 g of body weight (bw) of extract with and without 0.2 mg per 100 g bw peritoneal cyclophosphamide. There was no genotoxicity in the negative control or extract only groups and, compared to the cyclophosphamide control, there was a significant reduction in micronucleated polychromatic erythrocytes in all the groups given extract plus cyclophosphamide. For SMART larvae were fed 5 or 10 mg mL -1 of extract for seven days with and without 0.89 mg mL -1 of urethane given on day seven. The ST and HB flies showed no significant differences in spots between the negative control and the extract only groups. The number of urethane-induced spots was reduced by the highest concentration of extract for the ST flies and by both concentrations of extract for the HB flies. The results suggest that M. velutina extract is not genotoxic but is antigenotoxic.