Compostos carbonílicos α, ß-insaturados e hidrazonas sintéticas como antiparasitários / α, ß-Unsaturated carbonyl compounds and Synthetic hydrazones as antiparasitics

Apesar da grande relevância médica e social, e por serem responsáveis por grande parte das mortes em países subdesenvolvidos e em desenvolvimento as doenças negligenciadas (DN), ainda, não apresentam terapêutica eficaz. Dentre as diversas DN, doenças como a doença de Chagas, a Leishmaniose visceral e a malária, se destacam no cenário nacional, por terem alta incidência e prejuízos sociais. Os fármacos disponíveis para o tratamento destas parasitoses, apresentam alta toxicidade e, em alguns casos, resistência por parte dos parasitas. Assim sendo, faz-se necessário o planejamento e desenvolvimento de novos agentes quimioterápicos mais seguros e eficazes. Dentre as diferentes estratégias de planejamento de fármacos, selecionamos o planejamento de fármacos baseado na estrutura do ligante - LBDD (Ligand-Based Drug Design) - como base para desenvolvimento deste trabalho. Nesta estratégia, utiliza-se o conhecimento de moléculas (ligantes) e de suas atividades biológicas conhecidas previamente determinadas experimentalmente, como protótipos para a busca de novas entidades químicas com atividade biológica semelhante ou melhorada. Sendo assim, o presente trabalho teve como objetivo a síntese e avaliação biológica de moléculas bioativas para o tratamento de doenças parasitárias. Baseando-se no conhecimento prévio da atividade antiparasitária de compostos carbonílicos α,ß-insaturados e hidrazonas, foram sintetizados séries de compostos destas classes químicas na busca de novos agentes quimioterápicos. Os compostos obtidos foram avaliados contra a forma epimastigota de Trypanosoma cruzi, promastigota de Leishmania donovani, amastigota de Leishmania infantum e, também, determinou-se o seu grau de citotoxicidade (CC50) frente a células de macrófago humanos diferenciado (THP-1). As 31 moléculas obtidas foram caracterizadas por técnicas de ponto de fusão, RMN 1H e RMN 13C e avaliada sua pureza por HPLC. Os compostos da classe da cinamoil-hidrazonas apresentaram-se como promissores antiparasitários, mostrando atividade frente a forma promastigota (Leishmania donovani), 4 dos 12 compostos foram ativos (IC50= 1,27 - 13,68 µM) e frente a forma amastigota (Leishmania infantum), 10 dos 12 compostos apresentaram atividade (9,09 - 63,5 µM). Mesmo apresentando citotoxicidade moderada (CC50 = 8,83 - 87,47 µM), os compostos obtiveram valores inferiores ao fármaco de referência (doxorubicina: CC50 = 0,26 µM). Diante do exposto, o planejamento de fármacos realizado por LBDD mostrou-se bem-sucedido, pois a classe de cinamoil-hidrazonas mostrou-se promissora como antiparasitários, visto sua atividade na escala de baixo micromolar e moderada citotoxicidade em células humanas. Esses resultados assinalam que a classe de compostos descrita está passível a continuar sendo investigada no intuito de aprimorar os protótipos obtidos na busca de novos agentes quimioterápicos antiparasitários e desvendar os mecanismos de ação leishmanicida

Despite to the great medical and social relevance and the amount of deaths in underdeveloped and developing countries, neglected diseases (ND) still do not have an effective therapy. Among the various ND, illnesses such as Chagas disease, visceral leishmaniasis and malaria holds a great importance in the Brazilian scenario due to high incidence and social damage. The drugs available for the treatment of these parasitosis present high toxicity and, in some cases, resistance by the pathogens. Thus, the planning and development of new, safer and more effective chemotherapeutic substances are urgent needed. Among the different drug planning strategies, we selected ligand-based drug design (LBDD) as the basis for the development of this work. In this strategy, we use the knowledge of molecules (ligands) and their known biological activities previously determined experimentally, as prototypes to search for new chemical entities with similar or improved biological activity. Therefore, the present work aimed the synthesis and biological evaluation of bioactive molecules for the treatment of parasitic diseases. Based on previous knowledge of the antiparasitic activity of α,ß-unsaturated and hydrazone carbonyl compounds, series of compounds of these chemical classes were synthesized in search of new chemotherapeutic agents. The compounds obtained were evaluated against the epimastigote form of Trypanosoma cruzi, Leishmania donovani promastigote, Leishmania infantum amastigote and their cytotoxicity (CC50) against differentiated human macrophages (THP-1). The 31 molecules obtained were characterized by melting point, 1 H NMR and 13C NMR techniques and their purity were characterized by HPLC. The cinnamoyl hydrazone class compounds showed promising antiparasitic activity, showing activity against promastigote form (L. donovani), 4 of 12 compounds were active (IC50 = 1.27 - 13.68 µM) and amastigote form (L. infantum), 10 of the 12 compounds showed activity (9.09 - 63.5 µM). Even presenting moderate cytotoxicity (CC50 = 8.83 - 87.47 µM), the compounds had values below the reference drug (doxorubicin: CC50 = 0.26 µM). Considering the results, LBDD drug planning proved to be successful and the class of cinnamoyl hydrazones were promising as antiparasitics due to its activity in low micromolar scale and moderate cytotoxicity in human cells. These results indicate that the described class of compounds can be further investigated in order to improve the prototypes obtained in the search for new antiparasitic chemotherapeutic agents and to unravel the mechanisms of action of leishmanicidal molecules

Synthesis and physicochemical studies of vanillin chalcones / Síntesis y estudios fisicoquímicos de vainillin-chalconas

SUMMARY Some chalcone compounds are synthesized and their characterization was done by spectroscopic techniques such as IR, NMR and mass spectrometry. Some physicochemical properties such as acoustical properties, refractive index, conductance and partition coefficient have been studied for these synthesized compounds in N, N-dimethyl formamide and chloroform at 303.15 K. The studied properties are useful in QSAR studies and applications of these compounds in various other fields. It is observed that these parameters are affected by solvent and substitutions present in compounds.

RESUMEN Se sintetizaron algunos compuestos del tipo chalcona y su caracterizaron mediante técnicas espectroscópicas tales como IR, RMN y espectrometría de masa. Algunas propiedades fisicoquímicas tales como propiedades acústicas, índice de refracción, conductancia y coeficiente de reparto se estudiaron, para los compuestos sintetizados, en N,N-dimetil formamida y cloroformo a 303,15 K. Las propiedades estudiadas son útiles en estudios QSAR y en aplicaciones de estos compuestos en otros campos. Se observa que estos parámetros se ven afectados por el disolvente y las sustituciones presentes en los compuestos.

1-Octanol-water partition coefficient of some cyanopyridine and chalcone compounds / Coeficientes de reparto 1-octanol-agua de algunos compuestos derivados de cianopiridina y chalcona

SUMMARY The partition coefficients (P) of some synthesized cyanopyridine and chalcone compounds have been studied in 1-octanol-water system at different pH. It is observed that log P depends on pH and nature of substitution group present in the compounds. The central moiety also play important role to affect hydrophilic/ hydrophobic nature of compounds. There is no regular trend for the variation of log P with different pH.

RESUMEN Los coeficientes de reparto (P) de algunos compuestos sintetizados derivados de cianopiridina y chalcona se estudiaron en el sistema 1-octanol-agua a diferentes valores de pH. Se observa que log P depende del pH y de la naturaleza del grupo sustituyente presente en los compuestos. El grupo central también desempeña un papel importante en la naturaleza hidrofílica/hidrofóbica de los compuestos. No hay una tendencia regular para la variación de log P con el pH.

Ultrasonic behavior of various chalcones in some solvents at different temperatures / Comportamiento ultrasónico de varias chalconas en algunos disolventes a diferentes temperaturas

Ultrasonic velocity, density and viscosity of some synthesized chalcones were measured in N,N-dimethyl formamide and chloroform at different temperatures (298.15 to 318.15 K). From these experimental data, various acoustical parameters such as specific impedance (Z), adiabatic compressibility (k s), Rao's molar sound function (Rm), intermolecular free path length (Lf), solvation number (Sn), internal pressure (Π) have been calculated in order to understand the molecular interactions in the studied solutions. The results are interpreted in terms of molecular interactions occurring in the solutions.

La velocidad ultrasónica, la densidad y la viscosidad de soluciones de algunas chalconas sintéticas se midieron en N, N-dimetilformamida y cloroformo a diferentes temperaturas (desde 298,15 hasta 318,15 K). A partir de estos datos experimentales, se calcularon diversos parámetros acústicos tales como la impedancia específica (Z), la compresibilidad adiabática (k s), la función de sonido molar de Rao (Rm), la longitud de trayecto libre intermolecular (Lf), el número de solvatación (Sn) y la presión interna (Π), para comprender las interacciones moleculares en las soluciones estudiadas. Los resultados se interpretan en términos de las posibles interacciones moleculares que ocurren en las soluciones.

Biological activities of polyphenols from Polygonum lapathifolium / Actividades biológicas de polifenoles de Polygonum lapathifolium

Polygonum lapathifolium is an invasive plant spread worldwide, which has been used in traditional medicine for its biological activities. We studied chemical profile of the aerial part using HPLC/DAD/ESI-MS. Eight flavonoids, two chalcones and gallic acid were isolated, identified nad tested for their activity in seven experimental models (for antioxidant, alpha/beta-glucosidase inhibitory, antimicrobial, anticholineserase activity). Our results showed that P. lapathifolium is a valuable source of compounds with perspective biological activities...

Polygonum lapathifolium es una planta invasora cuya presencia se extiende por todo el mundo y que ha sido utilizada en la medicina tradicional por sus actividades biológicas. Analizamos el perfil químico de la parte superficial utilizando HPLC/DAD/ESI-MS. Ocho flavonoides, dos chalconas y ácido gálico fueron aislados, identificados y analizados en relación a sus actividades en siete modelos experimentales (de actividad antioxidante, alfa/beta-glucosidasa inhibitoria, antimicrobiana, anticholineserasa). Nuestros resultados demuestran que P. lapathifolium es una valiosa fuente de compuestos con actividades biológicas prometedoras...

Actividad inhibitoria de dihidroxifenil propenona sobre betalactamasas de Enterobacter cloacae: estudio preliminar en el desarrollo de fármacos para enfrentar la resistencia bacteriana / Inhibitory activity of dihydroxy-phenyl-propenone on betalactamase of Enterobacter cloacae : Preliminary study for drug development to overcome bacterial resistance

Introducción . Los microorganismos patógenos como Enterobacter cloacae producen betalactamasas que les confieren resistencia frente a los antibióticos betalactámicos; se ha identificado, además, la actividad limitada de los inhibidores enzimáticos, de modo que la única posibilidad de enfrentar la resistencia es el diseño de nuevos fármacos y su uso racional. Objetivo. Evaluar el efecto de la chalcona dihidroxifenil propenona sobre un aislamiento clínico de E. cloacae y sobre la betalactamasa aislada a partir de este microorganismo resistente como un aporte en la búsqueda de compuestos inhibidores de las betalactamasas. Materiales y métodos. Se sintetizó la chalcona dihidroxifenil propenona y se evaluó su efecto sobre el aislamiento clínico de E. cloacae para determinar la concentración inhibitoria mínima mediante el método de microdilución en caldo y con la betalactamasa purificada mediante cromatografía de afinidad se realizaron estudios espectrofotométricos de cinética enzimática. Resultados. La concentración inhibitoria mínima de la dihidroxifenil propenona sobre E. cloacae fue de 35 µg/ml; el porcentaje de recuperación de la betalactamasa a partir del microorganismo fue de 31,75 %; en el estudio cinético se evidenció actividad inhibitoria de acuerdo con los parámetros cinéticos de V max =1,7 x 10 -3 µM/minuto y K M´ =2330 µM. Conclusión. La chalcona dihidroxifenil propenona ejerce su actividad inhibitoria por medio de la interacción con la betalactamasa y, de esta manera, protege la integridad estructural de los antibióticos betalactámicos; dicho efecto sinérgico la convierte en un compuesto promisorio en la búsqueda de alternativas para enfrentar la resistencia bacteriana.

Introduction: Enterobacter cloacae is a pathogenic microorganism with the ability to produce betalactamase enzymes, which makes them resistant to betalactamic antibiotics. Additionally, the limited activity of enzymatic inhibitors has been identified, and, therefore, the design of new drugs and the promotion of their rational use are the only possibilities to overcome this problem. Objective: The aim of this research was to evaluate the effect of dihydroxy-phenyl-propenone on a clinical isolate of E. cloacae , as well as its activity on a betalactamase isolated from this resistant microorganism in order to contribute to the search for new betalactamase inhibitors. Materials and methods: Dihydroxy-phenyl-propenone chalcone was synthesized and evaluated on a clinical isolate of E. cloacae to determine the minimum inhibitory concentration by broth microdilution; once the betalactamase enzyme was purified by affinity chromatography, a spectrophotometric analysis was done to evaluate its kinetic activity. Results: The minimum inhibitory concentration value of dihydroxy-phenyl-propenone on E. cloacae was 35 µg/ml; the recovery percentage of the betalactamase from the microorganism was 31.75% and the kinetic parameters were V max =1.7 x 10 -3 µM/min and K M = 2330 µM, which show an important inhibitory activity. Conclusion: Dihydroxy-phenyl-propenone has shown inhibitory activity on betalactamase enzymes and the ability to protect the chemical integrity of betalactamic antibiotics; this synergistic effect turns it into a promising compound in the search for new alternatives to overcome bacterial resistance.

Avaliação das atividades antiproliferativa e antioxidante em frutos de Campomanesia pubescens / Evaluation of antioxidant and antiproliferative activities in fruits of Campomanesia pubescens

A investigação química dos extratos bioativos dos frutos de Campomanesia pubescens (Myrtaceae)resultou no isolamento de duas chalconas. Os compostos isolados foram identificados pelas análises espectroscópicas (1H, 13C e 2D RMN) e, por comparação com os dados descritos na literatura. A capacidade antioxidante dos extratos e frações foi determinada utilizando-se os ensaios de capacidade de absorção de oxigênio radical (ORAC-FL) e de DPPH; e os teores de fenólicos solúveis foram medidos utilizando-seo reagente de Folin-Ciocalteau. Os efeitos antiproliferativos dos extratos e de isolados de chalconas 1 e2 foram determinados in vitro contra as seguintes células cancerosas humanas U251 (glioma), UACC-62 (melanoma), MCF-7 (mama), NC1-ADR/RES (ovário resistente), 786,0 (rim), NCI-H460 (pulmão),PC-3 (próstata), OVCAR-3 (ovário), HT-29 (cólon) e K562 (leucemia), e contra linhagem celular não cancerígena VERO. O extrato hexânico e os compostos isolados de chalconas 1 e 2 demonstraram efeito antiproliferativo potente contra linhagens de células cancerosas com valores de inibição de crescimento total (TGI) menores dos aqueles observados na linhagem celular controle. A atividade mais elevada das chalconas 1 e 2 foi detectada nas células MCF-7, PC-3 e HT-29.

Chemical investigation on the bioactive extracts from fruits of Campomanesia pubescens (Myrtaceae)resulted in the isolation of two chalcones. The isolated compounds were identified by means of spectroscopicanalysis (1H, 13C and 2D NMR), and by comparing with the data reported in the specific literature.Antioxidant capacity of extracts and fractions was determined using the oxygen radical absorbancecapacity (ORAC-FL) and DPPH assays; and the total soluble phenolic contents were measured by usingFolin-Ciocalteau reagent. The anti-proliferative effects of the extracts and of the chalcone isolates 1 and2 were determined in vitro against human cancer cells lineages U251 (glioma), UACC-62 (melanoma),MCF-7 (breast), NC1-ADR/RES (ovarian-resistant), 786.0 (kidney), NCI-H460 (lung), PC-3 (prostate),OVCAR-3 (ovarian), HT-29 (colon) and K562 (leukemia), and against non-cancerous cell line VERO.Hexanic extract and chalcone isolated compounds 1 and 2 showed potent antiproliferative effect againstcancer cell lineages with lower total growth inhibition (TGI) values than those found in control cell line.The highest activity of the chalcones 1 and 2 was observed against the MCF-7, PC-3 and HT-29 cell lines.

Chalcones and N-acylhydrazones: direct analogues?: exploratory data analysis applied to potential novel antileishmanial agents

Leishmaniasis is an important health and social problem for which there is limited effective therapy. Chalcones and N-acylhydrazones have been studied as promising antileishmanial agents in enzymatic inhibition and in vitro assays. Since these chemical classes of compounds also resemble each other structurally, it would be useful to investigate whether they share direct analogy. Exploratory data analysis was applied to a library of chalcones and nitrated N-acylhydrazones assayed against Leishmania donovani to investigate their similarity. Under the conditions applied in the present study, the two classes did not present functional or structural analogy.

As leishmanioses são importantes problemas sociais e de saúde pública para os quais a terapia farmacológica atual é, ainda, limitada. Chalconas e N-acilidrazonas têm sido estudadas como promissores agentes leishmanicidas tanto em ensaios in vitro quanto em ensaios de inibição de cisteíno-proteases importantes para o parasito. Uma vez que estas classes de compostos apresentam similaridade bidimensional, seria interessante estudar se estes compostos guardariam relação de analogia direta entre si. Análise exploratória de dados foi aplicada, então, à biblioteca de chalconas e N-acilidrazonas nitradas ensaiadas contra Leishmania donovani para investigar suas relações de similaridade. Os resultados mostraram que, ao menos sob as condições consideradas neste estudo, as duas classes de compostos não apresentam analogia estrutural e funcional simultaneamente, embora elas apresentem alguma similaridade estrutural.