Antifungal activity of schinol and a new biphenyl compound isolated from Schinus terebinthifolius against the pathogenic fungus Paracoccidioides brasiliensis

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to isolate and identify the antifungal compounds from the extracts of <it>Schinus terebinthifolius </it>(Anacardiaceae) against clinical isolates of the pathogenic fungus <it>Paracoccidioides brasiliensis</it>.</p> <p>Methods</p> <p>The hexane and dichlomethane fractions from leaves and stems of <it>S. terebinthifolius </it>were fractionated using several chromatography techniques to afford four compounds.</p> <p>Results</p> <p>The compounds isolated from <it>S. terebinthifolius </it>were identified as schinol (<b>1</b>), a new biphenyl compound, namely, 4'-ethyl-4-methyl-2,2',6,6'-tetrahydroxy[1,1'-biphenyl]-4,4'-dicarboxylate (<b>2</b>), quercetin (<b>3</b>), and kaempferol (<b>4</b>). Compounds <b>1 </b>and <b>2 </b>were active against different strains of <it>P. brasiliensis</it>, showing a minimal inhibitory concentration value against the isolate Pb B339 of 15.6 μg/ml. The isolate Pb 1578 was more sensitive to compound <b>1 </b>with a MIC value of 7.5 μg/ml. Schinol presented synergistic effect only when combined with itraconazole. The compounds isolated from S. <it>terebinthifolius </it>were not able to inhibit cell wall synthesis or assembly using the sorbitol assay.</p> <p>Conclusion</p> <p>This work reveals for the first time the occurrence of compound <b>2 </b>and discloses activity of compounds <b>1 </b>and <b>2 </b>against several clinical isolates of <it>P. brasiliensi</it>s. These results justify further studies to clarify the mechanisms of action of these compounds.</p

IFN-γ Production Depends on IL-12 and IL-18 Combined Action and Mediates Host Resistance to Dengue Virus Infection in a Nitric Oxide-Dependent Manner

Dengue is a mosquito-borne disease caused by one of four serotypes of Dengue virus (DENV-1–4). Severe dengue infection in humans is characterized by thrombocytopenia, increased vascular permeability, hemorrhage and shock. However, there is little information about host response to DENV infection. Here, mechanisms accounting for IFN-γ production and effector function during dengue disease were investigated in a murine model of DENV-2 infection. IFN-γ expression was greatly increased after infection of mice and its production was preceded by increase in IL-12 and IL-18 levels. In IFN-γ−/− mice, DENV-2-associated lethality, viral loads, thrombocytopenia, hemoconcentration, and liver injury were enhanced, when compared with wild type-infected mice. IL-12p40−/− and IL-18−/− infected-mice showed decreased IFN-γ production, which was accompanied by increased disease severity, higher viral loads and enhanced lethality. Blockade of IL-18 in infected IL-12p40−/− mice resulted in complete inhibition of IFN-γ production, greater DENV-2 replication, and enhanced disease manifestation, resembling the response seen in DENV-2-infected IFN-γ−/− mice. Reduced IFN-γ production was associated with diminished Nitric Oxide-synthase 2 (NOS2) expression and NOS2−/− mice had elevated lethality, more severe disease evolution and increased viral load after DENV-2 infection. Therefore, IL-12/IL-18-induced IFN-γ production and consequent NOS2 induction are of major importance to host resistance against DENV infection

PCR for Diagnosis of Paracoccidioidomycosis

A PCR assay based on oligonucleotide primers derived from the sequence of the gene coding for the 43,000-Da (gp43) antigen was developed to detect Paracoccidioides brasiliensis DNA in sputa. In the standardized conditions, it could detect 10 cells/ml of sputum, providing sufficient accuracy to be useful for diagnosis of paracoccidioidomycosis

Correlation of the in vitro antifungal drug susceptibility with the in vivo activity of fluconazole in a murine model of cerebral infection caused by Cryptococcus gattii

Forty Cryptococcus gattii strains were submitted to antifungal susceptibility testing with fluconazole, itraconazole, amphotericin B and terbinafine. The minimum inhibitory concentration (MIC) ranges were 0.5-64.0 for fluconazole, < 0.015-0.25 for itraconazole, 0.015-0.5 for amphotericin B and 0.062-2.0 for terbinafine. A bioassay for the quantitation of fluconazole in murine brain tissue was developed. Swiss mice received daily injections of the antifungal, and their brains were withdrawn at different times over the 14-day study period. The drug concentrations varied from 12.98 to 44.60 mu g/mL. This assay was used to evaluate the therapy with fluconazole in a model of infection caused by C. gattii. Swiss mice were infected intracranially and treated with fluconazole for 7, 10 or 14 days. The treatment reduced the fungal burden, but an increase in fungal growth was observed on day 14. The MIC for fluconazole against sequential isolates was 16 mu g/mL, except for the isolates obtained from animals treated for 14 days (MIC = 64 mu g/mL). The quantitation of cytokines revealed a predominance of IFN-gamma and IL-12 in the non-treated group and elevation of IL-4 and IL-10 in the treated group. Our data revealed the possibility of acquired resistance during the antifungal drug therapy.Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)Fundacao de Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG)[APQ-2864-07]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[2008/04289-7]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[2008/56707-7]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP