Evaluation of the in vitro susceptibility and emergence of mutants resistant to ciprofloxacin among multidrug resistant clinical isolates.

Two hundred and seventy-seven multidrug resistant clinical isolates [K. pneumoniae, (N = 87); E coli, (N = 30); Salmonella typhimurium (N = 100); P. aeruginosa, (N = 30); S. aureus, (N = 30)] from hospitalized patients specimens, were tested in vitro for sensitivity to Ciprofloxacin. Application of the disk diffusion test and determination of the minimal inhibitory concentration by the microdilution method indicated that, almost all isolates were sensitive to the drug. Overall, S. aureus and P. aeruginosa were the less sensitive organisms. Ciprofloxacin-resistant mutants occurred at frequencies of > or = 10(-5)/CFU.

Assessment of DNA damage by extracts and fractions of Strychnos pseudoquina, a Brazilian medicinal plant with antiulcerogenic activity

Strychnos pseudoquina St. Hil. is a native plant of the Brazilian Savannah, used in popular medicine to treat a number of conditions. Since it contains large quantities of alkaloids with proven antiulcer activity, we tested the genotoxic potential of crude extracts and fractions containing alkaloids and flavonoids from the leaves of this plant, on Salmonella typhimurium and performed the micronucleus test on peripheral blood cells of mice treated in vivo. The results showed that the methanol extract of the leaves of S. pseudoquina is mutagenic to the TA98 (-S9) and TA100 (+S9, -S9) strains of Salmonella. The dichloromethane extract was not mutagenic to any of the tested strains. Fractions enriched with alkaloids or flavonoids were not mutagenic. In vivo tests were done on the crude methanol extract in albino Swiss mice, which were treated, by gavage, with three different doses of the extract. The highest dose tested (1800 mg/kg b.w.) induced micronuclei after acute treatment, confirming the mutagenic potential of the methanol extract of the leaves of S. pseudoquina. In high doses, constituents of S. pseudoquina compounds act on DNA, causing breaks and giving rise to micronuclei in the blood cells of treated animals. © 2006 Elsevier Ltd. All rights reserved.

Toxicidade de fármacos nitrofurânicos

During the structural designing of new drugs, it is possible predict the influence of specific chemical groups on pharmacological activity. Among these, the nitro group has potential antiparasitic activity, being present in many antimicrobial drugs, such as metronidazole, nitrofurazone, furazolidone, oxamniquine and chloramphenicol. Also, the introduction of the nitro group into a molecule can modify the physicochemical and electronic properties of the substance. Besides antimicrobial drugs, this group is also found in other drug classes, such as antiulcer, anti-inflamatory and anxiolytic. However, the use of the nitro group in drug design has encountered restrictions, due to the associated toxicity. This article is a review of the toxicity of nitrofuran compounds, as well the possible mechanisms involved and the strategy of latentiation by molecular modification to decrease their toxicity.

Mutagenic effect of native species of the Brazilian Cerrado with anti-ulcerogenic activity

Neea theifera Oerted (Nyctaginaceae), Guapira noxia Linn. (Nyctaginaceae) and Hancornia speciosa Gomes (Apocynaceae) are plant species found in Brazilian Cerrado used popularly for the treatment of gastric ulcers. Here they are assessed for mutagenic activity by analysis of the reverse mutations induced in Salmonella typhimurium strains TA100, TA98, TA102 and TA97a, by extracts of the plants, with and without metabolic activation. Methanol and chloroform extracts of N. theifera and G. noxia and methanolic and aqueous extracts of H. speciosa were tested at five different concentrations. It was found that only the methanolic extract of H. speciosa exhibited a positive mutagenic effect, on strains TA98 and TA100 in the absence of metabolic activation. The phytochemical analysis of the species suggested that condensed tannins are the main compounds responsible for the observed effect.

Mutagenic activity of glycoallkaloids from Solanum palinacanthum dunal (Solanaceae) found in the Brazilian cerrado

Solanaceous plants are widely distributed around the world and they are traditionally used as drugs for the treatment of cancer and herpes, and include familiar foods such as potato, tomato and eggplant and some berries popular in Brazil. As part of a program of research on pharmacologically active new molecules, the aim in this study was to assess the mutagenic effects of Solanum palinacanthum, known popularly as joá. The crude 95% ethanol extract and purified solamargine obtained from the fruits of S. palinacanthum Dunal were investigated by the Ames test, using the Salmonella typhimurium strains TA98, TA97a, TA100 and TA102 as test organisms, with and without metabolic activation. The concentrations tested ranged from 0.07 to 15.0 mg/plate for the crude ethanolic extract and from 1.25 to 5.0 mg/plate for the solamargine. The results showed a mutagenic effect of both the extract and the solamargine in the TA98 strain (without metabolic activation). The present study showed the potential mutagenicity and suggests confirming this effect in other models, before recommending their indiscriminate consumption by the population.

Mutagenic and genotoxic effect of hydroxyurea

The hydroxyurea, a cytotoxic drug, is the mainly available therapeutical strategy for the treatment of sickle cell disease. This study aimed to evaluate the mutagenic and genotoxic potential of the hydroxyurea through the Salmonella/Microsome assay and micronucleus test in peripheral blood of mice. The doses were evaluated at 29.25-468 μmol/plate in Salmonella/Microsome assay in presence and absence of metabolic activation the drug. In the micronucleus test the doses were evaluated at 12.5; 25; 50; 75 and 100 mg/kg. The results show that hydroxyurea present mutagenic activity in TA98 and TA100 in doses above 117 μmol/plate and 234 μmol/plate respectively. The drug induced a significant increase in the frequency of micronuclei in reticulocytes of mice at concentrations of 50, 75 and 100 mg/kg, compared to negative control (water). These results demonstrated the mutagenic and genotoxic potential of hydroxyurea. © 2011 Santos et al.

Antibacterial activity of oregano essential oil against foodborne pathogens

Purpose: This paper aims to evaluate in vitro antibacterial activity of oregano essential oil against foodborne pathogens as a starting point for the use of spice as a natural preservative in food. Design/methodology/approach: Disc and well-diffusion assays were performed to investigate antibacterial activity of oregano essential oil against six bacteria strains: Bacillus cereus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella Typhimurium. Three concentrations of oregano essential oil were employed: 1.0 percent, 2.0 percent and 5.0 percent. Bacterial growth inhibition was determinate as the diameter of the inhibition zones. Findings: Oregano essential oil showed antibacterial activity against spoilage microorganisms, at different concentrations, except for P. aeruginosa. There was a significant difference between methodologies only for the microorganism S. aureus. The results provided evidence of the existence of significant differences among the concentrations of oregano essential oil for each microorganism evaluated. Research limitations/implications: Although the research for this paper involved only oregano essential oil, it provided a starting-point for further investigations concerning spices as natural preservatives for food systems. Practical implications: Disc and well-assays were found to be simple and reproducible practical methods. Other spices, their essential oil and extracts might be researched against other micro-organisms. Furthermore, in situ studies need to be performed to evaluate possible interactions between essential oils and compounds naturally present in food against microbial strains. Social implications: The imminent adoption of measures to reduce the use of additives in foods and the reduction on using such compounds. Originality/value: This study provides insights that suggest a promising exploratory development of food natural preservative against spoilage microorganisms in food systems by the use of oregano essential oil. © Emerald Group Publishing Limited.

CYP-450 isoenzymes catalyze the generation of hazardous aromatic amines after reaction with the azo dye Sudan III

This work describes the mutagenic response of Sudan III, an adulterant food dye, using Salmonella typhimurium assay and the generation of hazardous aromatic amines after different oxidation methods of this azo dye. For that, we used metabolic activation by S9, catalytic oxidation by ironporphyrin and electrochemistry oxidation in order to simulate endogenous oxidation conditions. The oxidation reactions promoted discoloration from 65% to 95% of Sudan III at 1×10-4molL-1 and generation of 7.6×10-7molL-1 to 0.31×10-4molL-1 of aniline, o-anisidine, 2-methoxi-5-methylaniline, 4-aminobiphenyl, 4,4'-oxydianiline; 4,4'-diaminodiphenylmethane and 2,6-dimethylaniline. The results were confirmed by LC-MS-MS experiments. We also correlate the mutagenic effects of Sudan III using S. typhimurium with the strain TA1535 in the presence of exogenous metabolic activation (S9) with the metabolization products of this compound. Our findings clearly indicate that aromatic amines are formed due to oxidative reactions that can be promoted by hepatic cells, after the ingestion of Sudan III. Considering that, the use of azo compounds as food dyestuffs should be carefully controlled. © 2013 Elsevier Ltd.

Estrogenic and mutagenic activities of crotalaria pallida measured by recombinant yeast assay and ames test

Background: Crotalaria pallida Ailton is a plant belonging to the Fabaceae family, popularly known as rattle or rattlesnake and used in traditional medicine to treat swelling of the joints and as a vermifuge. Previous pharmacological studies have also reported anti-inflammatory, antimicrobial and antifungal activities. Nevertheless, scientific information regarding this species is scarce, and there are no reports related to its possible estrogenic and mutagenic effects. Thus, the purpose of the present study was to investigate the estrogenic potential of C. pallida leaves by means of the Recombinant Yeast Assay (RYA), seeking an alternative for estrogen replacement therapy during menopause; and to reflect on the safe use of natural products to assess the mutagenic activity of the crude extract from C. pallida leaves, the dichloromethane fraction and stigmasterol by means of the Ames test.Methods: The recombinant yeast assay with the strain BY4741 of Saccharomyces cerevisiae, was performed with the ethanolic extract, dichloromethane fraction and stigmasterol isolated from the leaves of C. pallida. Mutagenic activity was evaluated by the Salmonella/microsome assay (Ames test), using the Salmonella typhimurium tester strains TA100, TA98, TA97 and TA102, with (+S9) and without (-S9) metabolization, by the preincubation method.Results: All samples showed estrogenic activity, mainly stigmasterol. The ethanolic extract from C. pallida leaves showed mutagenic activity in the TA98 strain (-S9), whereas dichloromethane fraction and stigmasterol were found devoid of activity.Conclusion: Considering the excellent estrogenic activity performed by stigmasterol in the RYA associated with the absence of mutagenic activity when evaluated by the Ames test, stigmasterol becomes a strong candidate to be used in hormone replacement therapy during menopause. © 2013 Boldrin et al.; licensee BioMed Central Ltd.

Antitumour and anti-inflammatory effects of palladium(II) complexes on Ehrlich tumour

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Atividade mutagênica e ativadora da resposta imune celular induzidas por Byrsonima crassa Niedenzu e Byrsonima intermedia A.Juss. (Malpighiaceae)

Pós-graduação em Biociências e Biotecnologia Aplicadas à Farmácia - FCFAR

Atividade antibacteriana de óleos essenciais de especiarias em alimentos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracteres epidemiológicos de surtos de doenças diarréicas agudas ocorridas em núcleos receptores turísticos do Estado de São Paulo

Pós-graduação em Alimentos e Nutrição - FCFAR

Efeitos da instilação de morfina na inflamação ocular induzida experimentalmente em coelhos

Pós-graduação em Cirurgia Veterinária - FCAV

Avaliação da atividade mutagênica e fitoestrogênica das plantas Davilla nitida Vahl. e Davilla elliptica St. Hil (Dilleniaceae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)