Evaluation Of The Mutagenicity And Antimutagenicity Of Ziziphus Joazeiro Mart. Bark In The Micronucleus Assay.

The aim of this study was to evaluate the mutagenicity (clastogenicity/aneugenicity) of a glycolic extract of Ziziphus joazeiro bark (GEZJ) by the micronucleus assay in mice bone marrow. Antimutagenic activity was also assessed using treatments associated with GEZJ and doxorubicin (DXR). Mice were evaluated 24-48 h after exposure to positive (N-nitroso-N-ethylurea, NEU - 50 mg.kg(-1) and DXR - 5 mg.kg(-1)) and negative (150 mM NaCl) controls, as well as treatment with GEZJ (0.5-2 g.kg(-1)), GEZJ (2 g.kg(-1)) + NEU and GEZJ (2 g.kg(-1)) + DXR. There were no significant differences in the frequencies of micronucleated polychromatic erythrocytes in mice treated with GEJZ and GEJZ + DXR compared to the negative controls, indicating that GEZJ was not mutagenic. Analysis of the polychromatic:normochromatic erythrocyte ratio revealed significant differences in the responses to doses of 0.5 g.kg(-1) and 1-2 g.kg(-1) and the positive control (NEU). These results indicated no systemic toxicity and moderate toxicity at lower and higher doses of GEZJ. The lack of mutagenicity and systemic toxicity in the antimutagenic assays, especially for treatment with GEZJ + DXR, suggested that phytochemical compounds in Z. joazeiro bark attenuated DXR-induced mutagenicity and the moderate systemic toxicity of a high dose of Z. joazeiro bark (2 g.kg(-1)). Further studies on the genotoxicity of Z. joazeiro extracts are necessary to establish the possible health risk in humans and to determine the potential as a chemopreventive agent for therapeutic use.37428-3

Nongenotoxic effects and a reduction of the DXR-induced genotoxic effects of Helianthus annuus Linné (sunflower) seeds revealed by micronucleus assays in mouse bone marrow

BACKGROUND: This research evaluated the genotoxicity of oil and tincture of H. annuus L. seeds using the micronucleus assay in bone marrow of mice. The interaction between these preparations and the genotoxic effects of doxorubicin (DXR) was also analysed (antigenotoxicity test). METHODS: Experimental groups were evaluated at 24-48 h post treatment with N-Nitroso-N-ethylurea (positive control – NEU), DXR (chemotherapeutic), NaCl (negative control), a sunflower tincture (THALS) and two sources of sunflower oils (POHALS and FOHALS). Antigenotoxic assays were carried out using the sunflower tincture and oils separately and in combination with NUE or DXR. RESULTS: For THALS, analysis of the MNPCEs showed no significant differences between treatment doses (250–2,000 mg.Kg(-1)) and NaCl. A significant reduction in MNPCE was observed when THALS (2,000 mg.Kg(-1)) was administered in combination with DXR (5 mg.Kg(-1)). For POHALS or FOHALS, analysis of the MNPCEs also showed no significant differences between treatment doses (250–2,000 mg.Kg(-1)) and NaCl. However, the combination DXR + POHALS (2,000 mg.Kg(-1)) or DXR + FOHALS (2,000 mg.Kg(-1)) not contributed to the MNPCEs reduction. CONCLUSIONS: This research suggests absence of genotoxicity of THALS, dose-, time- and sex-independent, and its combination with DXR can reduce the genotoxic effects of DXR. POHALS and FOHALS also showed absence of genotoxicity, but their association with DXR showed no antigenotoxic effects

Genotoxic and cytotoxic potential of food azodyes: preclinical safety assessment using the in vivo micronucleus assay: Potencial genotóxico e citotóxico de azocorantes alimentícios: avaliação de segurança pré-clínica usando o ensaio do micronúcleo in vivo

This study evaluated the genotoxic effects of azodyes (ponceau 4R, red 40, sunset yellow and tartrazine) by the use of in vivo micronucleus assays. Swiss albinus young adult mice of both sexes, healthy and heterogeneous, were used in the micronucleus assay. Groups of animals were treated using a single dosing regimen and euthanized at 24 and 48 hours. The study design included treatment groups (0.5, 1.0 and 2 g/kg of azodyes) and negative (150 mM NaCl) and positive (50 mg/kg of NEU) control groups. Bone marrow polychromatic (PCE) and normochromatic (NCE) erythrocytes and micronucleated PCE (MNPCE) were statistically analyzed: frequency and PCE:NCE ratio. For animal groups treated with all azodyes, analyses of the frequency of MNPCEs and PCE/NCE ratio showed significant differences between the treatment groups (0.5-2 g/kg) and the control groups (NaCl and NEU). Each azodye exhibited genotoxic and systemic toxic effects correlated to treatment dose, time of euthanasia, and sex of the animal. The data suggest potential clastogenic and/or aneugenic effects that can potentiate systemic toxic risks associated with the azodyes whether the genotoxicity be dependent on dose (ponceau 4R, sunset yellow, and tartrazine), time (ponceau 4R, red 40, and sunset yellow), or sex (red 40 and tartrazine)

Isoenzyme genotyping and phylogenetic analysis of oxacillin-resistance Staphylococcus aureus isolates

e propagation of S. aureus in hospital and dental environments is considered an important public health problem since resistant strains can cause serious infections in humans. The genetic variability of 99 oxacillin-resistant S. aureus isolates (ORSA) from the dental patients (oral cavity) and environments (air) was studied by isoenzyme genotyping. Methods: S. aureus isolates were studied using isoenzyme markers (alcohol dehydrogenase, sorbitol dehydrogenase, mannitol-1-phosphate dehydrogenase, malate dehydrogenase, glucose dehydrogenase, D-galactose dehydrogenase, glucose-6-phosphate dehydrogenase, catalase and /-esterase) and genetic (Neis statistics) and cluster analysis (UPGMA algorithm). Results: A highly frequent polyclonal pattern was observed in this population of ORSA isolates, suggesting various sources of contamination or microbial dispersion. Genetic relationship analysis showed a high degree of polymorphism between the strains, and it revealed three taxa (A, B and C) distantly genetically related (0.653dij1.432) and fifteen clusters (I to XV) moderately related (0.282dij0.653). These clusters harbored two or more highly related strains (0dij0.282), and the existence of microevolutionary processes in the population of ORSA. Conclusion: This research reinforces the hypothesis of the existence of several sources of contamination and/or dispersal of ORSA of clinical and epidemiologically importance, which could be associated with carriers (patients) and dental environmental (air)