Synthesis of novel papulacandin D analogs and evaluation of their antifungal potential

Systemic fungal infections are a growing problem in contemporary medicine and few drugs are licensed for therapy of invasive fungal infections. Differences between fungi and humans, like the presence of a cell wall in fungal cells, can be explored for designing new drugs. (1,3)-β-D-glucan synthase, an enzyme that catalyzes the synthesis of (1,3)-β-D-glucan, a structural and essential component of the fungal cell wall, is absent in mammals and this makes it an excellent target for the development of new antifungal agents. Papulacandins are a family of natural antifungal agents targeting (1,3)-β-D-glucan synthase. In this study we describe the synthesis and biological evaluation of two new Papulacandin analogs as potential (1,3)-β-D-glucan synthase inhibitors.

Synthesis, antileishmanial activity and QSAR studies of 2-chloro- N -arylacetamides

ABSTRACT We describe herein the synthesis and evaluation of the antileishmanial activity against promastigote forms of Leishmania amazonensis and cytotoxicity to murine macrophages of a series of 2-chloro-N-arylacetamide derivatives. All compounds were active, except one (compound 3). Compound 5 presented the most promising results, showing good antileishmanial activity (CI50=5.39±0.67 µM) and moderate selectivity (SI=6.36), indicating that further development of this class is worthwhile. Preliminary QSAR studies, although not predictive, furnished some insights on the importance of electronic character of aryl substituent to biological activity, as well as an indirect influence of hydrophobicity on activity.

Synthesis and evaluation of platinum complexes with potential antitumor activity

Abstract A novel series of platinum (II) complexes was synthesized and the complexes were evaluated for their in vitro cytotoxicity against four human cancer cells lines. Five platinum complexes showed activity against at least one tumor cell line. Complexes 3 and 6 were promising, being active, at micromolar concentrations, against all the assayed tumor cell lines. Compound 3 was selected for further studies in mice with Ehrlich solid tumors and it was able to reduce the rate of tumor growth significantly during the first seven days. However, at the end of the experiments, there was no significant difference between the group of animals treated with 3 and the control group. The low solubility of the compound in the assay conditions can explain, at least in part, these results.

The activity of a metronidazole analogue and its β-cyclodextrin complex against Trypanosoma cruzi

In this study we prepared an inclusion complex between an iodide analogue of metronidazole (MTZ-I) and cyclodextrin (CD) to develop a safer and more effective method of treating Trypanosoma cruzi infections. According to our results, MTZ-I and MTZ-I:β-CD were 10 times more active than MTZ, demonstrating that the presence of an iodine atom on the side chain increased the trypanocidal activity while maintaining its cytotoxicity. The selective index shows that MTZ-I was 10 times more active against T. cruzi than it was against mammalian cells. The modification of MTZ side chains provides a promising avenue for the development of new drugs.

Caracterização físico-química de complexos de insulina: dimetil-beta-ciclodextrina e insulina: hidroxipropil-beta-ciclodextrina e avaliação da influência do tipo de complexo na produção de microesferas biodegradáveis / Physico-chemical caracterization of insulin: dimethyl-beta-cyclodextrin and insulin:hydroxypropil-beta-cyclodextrin complexes and evaluation of the kind of complexes on the biodegradable microspheres preparation

A etapa principal na ativação e ligação da insulina ao seu receptor é a dissociação dos hexâmeros do hormônio, normalmente presente nas preparações farmacêuticas, para a forma monomérica bioativa. A utilização de diferentes ciclodextrinas (CDs) como adjuvantes em formulações contendo insulina vem sendo explorada e os estudos realizados demonstram que estas substâncias podem aumentar a absorção da insulina principalmente por diminuírem sua capacidade de formar dímeros e hexâmeros em meio aquoso. No presente trabalho, complexos de insulina:hidroxipropil-beta-ciclodextrina (INS:HP-beta-CD) e insulina:dimetil-beta-ciclodextrina (INS:DM-beta-CD) foram caracterizados utilizando técnicas de titulação calorimétrica isotérmica e espalhamento dinâmico de luz. Por meio da titulação calorimétrica foram determinados os parâmetros termodinâmicos de interação entre a insulina e as CDs utilizadas, sugerindo que o mecanismo de complexação ocorre com aumento de entropia para ambos os sistemas. Os experimentos de espalhamento dinâmico de luz não indicaram diminuição do diâmetro hidrodinâmico das espécies moleculares de insulina após a complexação com as CDs. Os complexos INS:HP-beta-CD e INS:DM-beta-CD foram encapsulados em microesferas (MEs) de PLGA 50:50. A caracterização das MEs obtidas revelou aumento considerável na taxa de encapsulamento de insulina quando complexada com as CDs sem que ocorresse diferença significativa no diâmetro das partículas em função da complexação.

The main stage in the linking and activation of the specific receptors by the insulin is the dissociation of this peptide hexamers, normally present in pharmaceutical formulations, in the monomeric active form. Because of this, the use of different cyclodextrins as adjuvants in the formulations containing insulin has been explored and the realized studies have demonstrated that the cyclodextrins can increase the absorption of the insulin mainly by reducing the ability of insulin oligomerization in aqueous media. In this work, complexes of INS:HP-beta-CD and INS:DM-beta-CD have been characterized by the use of isothermal calorimetry titration (ICT) and dynamic scattering of light. By means of ICT, the thermodynamic parameters of interaction between insulin and the cyclodextrins have been determined, and it was observed that the complexation occurs with an increase of entropy for both systems. The experiments of dynamic scattering of light have not showed reduction in the size of insulin particles, which could indicate the dissociation of insulin hexamers after the complexation with cyclodextrins. Then, the INS: HP-beta-CD and INS:DM-beta-CD complexes were encapsulated in PLGA microspheres. These systems were characterized and it was not observed any significant difference in the microspheres diameter, but a considerable increase in the hormone loading after the complexation with HP-beta-CD and DM-beta-CD was shown.

Agentes antitumorais inibidores da angiogênese: modelos farmacofóricos para inibidores da integrina alfa nu beta3 / Angiogenesis inhibitors antitumor agents: pharmacophore models to alfuh noo baytuh3 antagonists

O câncer é, atualmente, uma das principais causas de morte no mundo. A angiogênese, formação de novos vasos capilares a partir de células endoteliais, é essencial para vários processos fisiopatológicos, tais como o desenvolvimento e a disseminação dos tumores. As integrinas são uma família de receptores de superfície que estão envolvidos na angiogênese, na qual a integrina alfa nu beta3 exerce papel importante. Os antagonistas da integrina alfa nu beta3 têm efeitos diretos na prevenção do crescimento, angiogênese e metástase tumorais. A avaliação in vitro frente à integrina alfa nu beta3 de coleções de ciclopeptídeos levou a compostos muito ativos e seletivos. Antagonistas não-peptídicos da integrina alfa nu beta3 também foram planejados e sintetizados. A partir da determinação da estrutura tridimensional da integrina alfa nu beta3 complexada com um inibidor, tornou-se possível o planejamento racional de ligantes com alta afinidade. Além disto, estes estudos permitiram a validação e o refinamento de modelo farmacofórico para os inibidores da integrina alfa nu beta3.

Cancer is one of the leading causes of death. Angiogenesis, the growth of new blood vessels, is essential for tumor development and spreading. Integrins are a family of surface receptors that are involved in angiogenesis. The alfuh noo baytuh3 integrin plays an important role in tumor angiogenesis. Alfuh noo baytuh3 inhibitors have direct effects to prevent tumor metastases, growth and angiogenesis. In vitro screening of cyclic peptide libraries led to highly active and alfuh noo baytuh3-selective compounds. Non-peptidic alfuh noo baytuh3 antagonists were also designed and synthesized. The crystal structure of the alfuh noo baytuh3 integrin in complex with RGD ligant allowed structure-based rational design of ligands and validation of pharmacophore model to alfuh noo baytuh3 antagonists.

Síntese e propriedades farmacológicas do p-Benziloxialilbenzeno (O-benzilchavicol) / Synthesis and pharmacological properties of p-Benzyloxyallylbenzene (O-benzylchavicol

O p-benziloxialilbenzeno (O-benzilchavicol) foi obtido por síntese envolvendo oito etapas e submetido a testes farmacológicos. Apresentou efeito anticonvulsivante e potenciou fortemente o tempo de sono induzido pelo pentobarbital.