Efficient Synthesis and Iodine-Functionalization of Pyrazoles via KIO3/PhSeSePh System under Acidic Conditions.

This manuscript reports a novel method for the direct iodination of the C-4 pyrazole ring generated in situ by the reaction of 1,1,3,3-tetramethoxypropane and various hydrazines. In this approach, potassium iodate (KIO3) is used as the iodinating agent and (PhSe)2 is used as catalysts under acidic conditions. This protocol provides a convenient method for the efficient synthesis of 4-iodo-1-aryl-1H-pyrazoles, valuable intermediates for several different coupling reactions.

Insecticidal activity of extracts of handroanthus impetiginosus on Plutella xylostella (Lepidoptera: plutellidae) larvae.

Plutella xylostella is considered the main pest of cabbage in Brazil and the world, causing damage of up to 100%. Thus, this study evaluated the insecticidal activity of extracts obtained from the fruits, seeds, bark, leaves, and flowers of Handroanthus impetiginosus against the diamondback moth, P. xylostella larvae. The seed extract showed the highest mortality (97.0%) compared to the control treatment. The LC50 values indicated that the seed and flower extracts (0.01003 and 0.01288 mg/L respectively) assumed the highest toxicity to P. xylostella larvae after 24 h of exposure. The results of this study indicated that the seeds extract is the most promising toxic extract, with measured mortality of approximately 97.0% for P. xylostella larvae after 144 h of exposure in kale plants. Seed extract showed the best insecticidal activity. Thus, this extract can be applied to develop an insecticide based on H. impetiginosus seed.

Antileishmanial Efficacy of the Calpain Inhibitor MDL28170 in Combination with Amphotericin B.

The necessity of drug combinations to treat leishmaniasis came to the surface mainly because of the toxicity of current treatments and the emergence of resistant strains. The calpain inhibitor MDL28170 has previously shown anti-Leishmania activity, therefore its use in association with standard drugs could provide a new alternative for the treatment strategy against leishmaniasis. In this study, we analyzed the potential of the combination of MDL28170 and the antileishmanial drug amphotericin B against Leishmania amazonensis and Leishmania chagasi. The compounds were tested in the combination of the ½ × IC50 value of MDL28170 plus the » × IC50 value of amphotericin B, which led to an increment in the anti-promastigote activity when compared to the single drug treatments. This drug association revealed several and severe morphophysiological changes on parasite cells, such as loss of plasma membrane integrity, reduced size of flagellum, and depolarization of mitochondrial membrane potential besides increased reactive oxygen species production. In addition, the combination of both drugs had a deleterious effect on the Leishmania-macrophage interaction, reflecting in a significant anti-amastigote action, which achieved a reduction of 50% in the association index. These results indicate that the combination treatment proposed here may represent a new alternative for leishmaniasis chemotherapy.

Bergenin Reduces Experimental Painful Diabetic Neuropathy by Restoring Redox and Immune Homeostasis in the Nervous System.

Diabetic neuropathy is a frequent complication of diabetes. Symptoms include neuropathic pain and sensory alterations-no effective treatments are currently available. This work characterized the therapeutic effect of bergenin in a mouse (C57/BL6) model of streptozotocin-induced painful diabetic neuropathy. Nociceptive thresholds were assessed by the von Frey test. Cytokines, antioxidant genes, and oxidative stress markers were measured in nervous tissues by ELISA, RT-qPCR, and biochemical analyses. Single (3.125-25 mg/kg) or multiple (25 mg/kg; twice a day for 14 days) treatments with bergenin reduced the behavioral signs of diabetic neuropathy in mice. Bergenin reduced both nitric oxide (NO) production in vitro and malondialdehyde (MDA)/nitrite amounts in vivo. These antioxidant properties can be attributed to the modulation of gene expression by the downregulation of inducible nitric oxide synthase (iNOS) and upregulation of glutathione peroxidase and Nrf2 in the nervous system. Bergenin also modulated the pro- and anti-inflammatory cytokines production in neuropathic mice. The long-lasting antinociceptive effect induced by bergenin in neuropathic mice, was associated with a shift of the cytokine balance toward anti-inflammatory predominance and upregulation of antioxidant pathways, favoring the reestablishment of redox and immune homeostasis in the nervous system. These results point to the therapeutic potential of bergenin in the treatment of painful diabetic neuropathy.

Chemical disorder determines the deviation of the Slater-Pauling rule for Fe2MnSi-based Heusler alloys: evidences from neutron diffraction and density functional theory.

Fe2MnSi fails to follow the Slater-Pauling rule. This phenomenon is thought to originate from either: (i) an antiferromagnetic arrangement of Mn ions at low temperature and/or (ii) chemical disorder. An important insight on this issue could be achieved by considering Fe2MnSi1-x Ga x compounds, thoroughly studied here by means of magnetization, neutron diffraction and density functional calculations (DFT). Our results indicate that chemical disorder (and not the antiferromagnetic arrangement) is responsible for the deviation of the Slater-Pauling rule on Fe2MnSi-based Heusler alloys. Furthermore, evidences suggest that Ga substitution into Si site favors the Fe/Mn disorder, further enhancing the observed deviation.

Fe3+ concentration dependence of photoacoustic absorption spectroscopy on ZnGa2O4 ceramic powders.

In this paper we present the photoacoustic spectroscopy of ZnGa2O4 with 5 and 10% of Fe3+. The ZnGa2O4 is a normal spinel, with Zn2+ ions in tetrahedral sites and Ga3+ ions in octahedral sites. It is expected for these hosts that Fe3+ ions occupy Ga3+ sites. Therefore, the optical properties would be associated to an octahedral symmetry. The energy levels were identified and the crystal field and electronic interaction parameters calculated with Tanabe-Sugano matrices for d5 configuration. We have also studied the dependence of the photoacoustic signal amplitude on the excitation light modulation frequency. Our results indicate that thermal expansion is the predominant phenomenon for the photoacoustic signal generation.