Synthesis and antimycobacterial activities of non-purine analogs of 6-aryl-9-benzylpurines; imidazopyridines, pyrrolopyridines, benzimidazoles and indoles

6,9-Disubstituted purines and 7-deazapurines are known to be powerful inhibitors of Mycobacterium tuberculosis (Mtb) in vitro. Analogs modified in the six-membered ring (imidazopyridines, pyrrolopyridines, benzimidazoles, and indoles) were synthesized and evaluated as Mtb inhibitors. The targets were prepared by functionalization on the bicyclic heterocycle or from simple pyridines. The results reported herein, indicate that the purine N-1, but not N-3, is important for binding to the unknown target. The 3-deazapurines appears to be slightly more active compared to the parent purines and slightly less active than their 7-deazapurine isomers. Removal of both the purine N-3 and N-7 did not result in further enhanced antimycobacterial activity but the toxicity towards mammalian cells was increased. Both 3-deaza and 3,7-dideazapurines exhibited a modest activity against of the Mtb isolate in the state of non-replicating persistence

Synthesis of non-purine analogs of 6-aryl-9-benzylpurines, and their antimycobacterial activities : compounds modified in the imidazole ring

Purine analogs modified in the five-membered ring have been synthesized and examined for antibacterial activity against Mycobacterium tuberculosis H37Rv in vitro employing the microplate alamar blue assay (MABA). The 9-deaza analogs were only found to be weak inhibitors, but the 8-aza-, 7-deaza- and 8-aza-7-deazapurine analogs studied displayed excellent antimycobacterial activities, some even substantially better than the parent purine. In the 7-deazapurine series, MIC values between 0.08 and 0.35 lM, values comparable or better than the reference drugs used in the study (MIC rifampicin 0.09 lM, MIC isoniazid 0.28 lM and MIC PA-824 0.44 lM). The five most active compounds were also examined against a panel of drug-resistant Mtb strain, and they all retained their activity. The compounds examined were significantly less active against M. tuberculosis in a state of non-replicating persistence (NRP). MIC in the low-oxygen-recovery assay (LORA)P60 lM. The 7-deazapurines were somewhat more toxic towards mammalian cells, but still the selectivity indexes were excellent. The non-purine analogs exhibit a selective antimycobacterial activity. They were essentially inactive against Staphylococcus aureus and Escherichia coli

2,6‐hexadecadiynoic acid and 2,6‐nonadecadiynoic acid: Novel synthesized acetylenic fatty acids as potent antifungal agents

The hitherto unknown 2,6‐hexadecadiynoic acid, 2,6‐nonadecadiynoic acid, and 2,9‐hexadecadiynoic acid were synthesized in two steps and in 11–18% overall yields starting from either 1,5‐hexadiyne or 1,8‐nonadiyne. Among all the compounds 2,6‐hexadecadiynoic acid displayed the best overall antifungal activity against both the fluconazole‐resistant Candida albicans strains ATCC 14053 and ATCC 60193, with a minimum inhibitory concentration (MIC of 11 μM), and against Cryptococcus neoformans ATCC 66031 (MIC\u3c5.7 μM). 2,9‐Hexadecadiynoic acid did not display any significant cytotoxicity against the fluconazole‐resistant C. albicans strains, but it showed fungitoxicity against C. neoformans ATCC 66031 with a MIC value of \u3c5.8 μM. Other FA, such as 2‐hexadecynoic acid, 5‐hexadecynoic acid, 9‐hexadecynoic acid, and 6‐nonadecynoic acid were also synthesized and their antifungal activities compared with those of the novel acetylenic FA, 2‐Hexadecynoic acid, a known antifungal FA, exhibited the best antifungal activity (MIC=9.4 μM) against the fluconazole‐resistant C, albicans ATCC 14053 strain, but it showed a MIC value of only 100 μM against C. albicans ATCC 60193. 2,6‐Hexadecadiynoic acid and 2‐hexadecynoic acid also displayed a MIC of 140–145 μM toward Mycobacterium tuberculosis H37Rv in Middlebrook 7H12 medium. In conclusion, 2,6‐hexadecadiynoic acid exhibited the best fungitoxicity profile compared with other analogues. This diynoic FA has the potential to be further evaluated for use in topical antifungal formulations

Attenuation of Mycobacterium species through direct and macrophage mediated pathway by unsymmetrical diaryl urea

Tuberculosis is a major threat for mankind and the emergence of resistance strain of Mycobacterium tuberculosis (Mtb) against first line antibiotics makes it lethal for human civilization. In this study, we have synthesized different diaryl urea derivatives targeting the inhibition of mycolic acid biosynthesis. Among the 39 synthesized molecules, compounds 46, 57, 58 and 86 showed MIC values ≤ 10 μg/ml against H37Rv and mc26030 strains. The best molecule with a methyl at ortho position of the first aromatic ring and prenyl group at the meta position of the second aromatic ring showed the MIC value of 5.2 μg/ml and 1 μg/ml against H37Rv and mc26030 respectively, with mammalian cytotoxicity of 163.4 μg/ml. The effective compounds showed selective inhibitory effect on mycolic acid (epoxy mycolate) biosynthesis in14C-radiolabelled assay. At the same time these molecules also executed their potent immunomodulatory activity by up-regulation of IFN-γ and IL-12 and down-regulation of IL-10.Fil: Velappan, Anand Babu. Sastra University; IndiaFil: Charan Raja, Mamilla R.. Sastra University; IndiaFil: Datta, Dhrubajyoti. Indian Institute of Science Education and Research Pune; IndiaFil: Tsai, Yi Ting. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Halloum, Iman. Université de Montpellier; Francia. Centre National de la Recherche Scientifique; FranciaFil: Wan, Baojie. University of Illinois; Estados UnidosFil: Kremer, Laurent. Université de Montpellier; Francia. Inserm; Francia. Centre National de la Recherche Scientifique; FranciaFil: Gramajo, Hugo Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Franzblau, Scott G.. University of Illinois; Estados UnidosFil: Kar Mahapatra, Santanu. Sastra University; IndiaFil: Debnath, Joy. Sastra University; Indi

Countercurrent Chromatography Fractions of Plant Extracts with Anti-Tuberculosis Activity

Samples of numerous plant species were received from the southwestern part of the USA, from Richard Spjut, and plant samples were collected here in Illinois. All were extracted with typical solvents, giving crude residues, some of which were subjected to chromatographic methods. Some of the crude residues and some of the fractions were tested for anti-tuberculosis activity and/or antibacterial activity. In a general way, bioactive natural products are dealt with very well by Liang & Fang. More specifically, the southwestern part of the United States has a large variety of indigenous plants many of which have not been investigated for their medicinal potential, and only very few have had their extracts separated into the individual compounds they may contain. But, some information is available for Native American herbal uses (Moerman,2003)

Repositioning Antitubercular 6-Nitro-2,3-dihydroimidazo[2,1-b][1,3]oxazoles for Neglected Tropical Diseases: Structure-Activity Studies on a Preclinical Candidate for Visceral Leishmaniasis.

6-Nitro-2,3-dihydroimidazo[2,1-b][1,3]oxazole derivatives were initially studied for tuberculosis within a backup program for the clinical trial agent pretomanid (PA-824). Phenotypic screening of representative examples against kinetoplastid diseases unexpectedly led to the identification of DNDI-VL-2098 as a potential first-in-class drug candidate for visceral leishmaniasis (VL). Additional work was then conducted to delineate its essential structural features, aiming to improve solubility and safety without compromising activity against VL. While the 4-nitroimidazole portion was specifically required, several modifications to the aryloxy side chain were well-tolerated e.g., exchange of the linking oxygen for nitrogen (or piperazine), biaryl extension, and replacement of phenyl rings by pyridine. Several less lipophilic analogues displayed improved aqueous solubility, particularly at low pH, although stability toward liver microsomes was highly variable. Upon evaluation in a mouse model of acute Leishmania donovani infection, one phenylpyridine derivative (37) stood out, providing efficacy surpassing that of the original preclinical lead

Development of (6 R)-2-Nitro-6-[4-(trifluoromethoxy)phenoxy]-6,7-dihydro-5 H-imidazo[2,1- b][1,3]oxazine (DNDI-8219): A New Lead for Visceral Leishmaniasis.

Discovery of the potent antileishmanial effects of antitubercular 6-nitro-2,3-dihydroimidazo[2,1- b][1,3]oxazoles and 7-substituted 2-nitro-5,6-dihydroimidazo[2,1- b][1,3]oxazines stimulated the examination of further scaffolds (e.g., 2-nitro-5,6,7,8-tetrahydroimidazo[2,1- b][1,3]oxazepines), but the results for these seemed less attractive. Following the screening of a 900-compound pretomanid analogue library, several hits with more suitable potency, solubility, and microsomal stability were identified, and the superior efficacy of newly synthesized 6 R enantiomers with phenylpyridine-based side chains was established through head-to-head assessments in a Leishmania donovani mouse model. Two such leads ( R-84 and R-89) displayed promising activity in the more stringent Leishmania infantum hamster model but were unexpectedly found to be potent inhibitors of hERG. An extensive structure-activity relationship investigation pinpointed two compounds ( R-6 and pyridine R-136) with better solubility and pharmacokinetic properties that also provided excellent oral efficacy in the same hamster model (>97% parasite clearance at 25 mg/kg, twice daily) and exhibited minimal hERG inhibition. Additional profiling earmarked R-6 as the favored backup development candidate

Actividad antimicobacteriana de algunas plantas de la flora colombiana

La incidencia actual de la tuberculosis a nivel mundial y la aparición de cepas de Mycobacterium tuberculosis multirresistentes a los agentes quimioterapeuticos hace necesaria la búsqueda de nuevas sustancias que puedan ser usadas para el control de la enfermedad. Las familias Myristicaceae, Magnoliaceae, Lauraceae y Piperaceae presentan lignanos, compuestos que pueden ser potenciales agentes antimicobacterianos. En esta investigación extractos y fracciones de Virola calophylla, V. flexuosa, Piper sp., P. hispidum, y Dugandiodendron sp. presentan un buena actividad antibacterial in vitro frente a M. tuberculosis H37Rv. También se reporta el aislamiento de compuestos del tipo lignano y de un flavonoide

O sistema PBL, problem-based learning, no ensino de medicina no Brasil : análise bibliográfica sobre a sua execução

Introdução: Entre as estratégias de ensino e aprendizagem utilizadas nas práticas pedagógicas, a Problem Based Learning (PBL) (Aprendizagem Baseada em Problemas) é utilizada desde 1960, em especial nos cursos de Medicina. Mesmo sendo uma estratégia valiosa, um dos seus obstáculos é a pouca prática dos alunos em atividades autodirigidas, pesquisa e construção coletiva do conhecimento. Objetivo: Rastrear elementos constitutivos da PBL através de dados colhidos em artigos pesquisados em sítios de divulgação científica; Avaliar, nos estudos selecionados, os aspectos positivos e negativos que estejam relacionados com a metodologia do Sistema PBL aplicada ao ensino médico no Brasil. Metodologia: Estudo bibliográfico de 13 textos utilizando um modelo de desconstrução, denominada Análise Textual Discursiva (ATD) que consiste em: transformação dos artigos em pedaços menores; análise textual; identificação de padrões convergentes e divergentes em relação a PBL; organização e síntese dos dados, culminando com a elaboração de estratégia adaptativa da PBL para o curso de Medicina. Resultados: Foram encontradas 116 citações que convergiam para referências positivos acerca da metodologia PBL e 40 citações que divergiam acerca dos pontos positivos. Os aspectos positivos como o desenvolvimento de atitudes e habilidades; desenvolvimento de competências anteriores ao curso; efeitos positivos depois de terminada a graduação, como autonomia de estudo e a articulação entre currículo e realidade profissional, representam pontos a serem reforçados na aula. Em contraponto, foi observado que dentre os negativos a não compreensão do papel do professor como tutor; necessidade de conteúdo formal tradicional pelos alunos e a expectativa que o professor retire as suas dúvidas são pontos a serem evitados. Conclusões: A metodologia PBL deverá servir como metodologia ativa para aproveitar ao máximo as habilidades que os alunos já apresentam, potencializando o aprendizado na educação médica em sala de aula. Palavras-Chave: PBL; curso de medicina; metodologia ativa; educação médica.ABSTRACT Introduction: Among the teaching and learning strategies used in teaching practices, the Problem Based Learning (PBL) (Problem Based Learning) has been used since 1960, especially in medical courses. Although a valuable strategy, one of its obstacles is the lack of practice of students in self-directed activities, research and collective construction of knowledge. Objective: Tracking constitutive elements of PBL through data collected on items surveyed in science communication sites and arrange them in order to develop a student's adaptation strategy to this methodological way. Evaluate the selected studies, the positive and negative aspects that are related to the methodology of PBL system applied to medical education in Brazil. Methodology: bibliographic study of 13 texts using a deconstruction model, called Discursive Textual Analysis (DTA) consisting of: transforming items into smaller pieces; textual analysis; identifying convergent and divergent patterns in relation to PBL; organization and synthesis of data, culminating with in the development of adaptive strategy of PBL to Medical Course. Results: It has been found 116 quotes that converged into positive notes about the PBL methodology and 40 quotes that differed about the positive ones. These quotations are placed in lines of analysis, based on a model of adaptation of the PBL student body. The positive aspects represent points to be reinforced in the classroom and the negative ones to be avoided. Conclusions: The PBL methodology should serve as active methodology to make the most of the skills that students already have, enhancing learning in medical education in the classroom Keywords: PBL; medical schools; active methodology; medical education