Synthesis, antimicrobial evaluation and in silico studies of the (E)-3-(aryl)-5-styryl-1,2,4-oxadiazoles

In recent years, investigations in the field of oxadiazoles have been intensified due to their numerous therapeutic uses. Oxadiazoles are a class of compounds that exhibit several biological applications, citing antimicrobial, anti-inflammatory, anti-diabetic, anthelmintic, anti-tumor, among others. Encouraged by the biological potential of oxadiazoles, were carried out synthesis, antimicrobial evaluation and in silica studies of five (E)-3-(aryl)-5-styryl-1,2,4-oxadiazoles. In this way, (Z)-aryl-N'-hydroxybenzimidamides and ethyl (E)-cinnamate were synthesized, which were subjected to an O-acylamidoxime reaction after by dehydration using microwave irradiation to form the oxadiazole nucleus. The compounds were characterized by spectroscopic techniques, while in vitro antimicrobial activity was evaluated against S. aureus, E. faecalis, E. coli, P. aeruginosa, and against the fungus C. utilis using the microplate microdilution method. Thus, (Z)-aryl-N'-hydroxybenzimidamides, ethyl (E)-cinnamate, and (E)-3-(aryl)-5-styryl-1,2,4-oxadiazoles were synthesized with yields ranging from moderate to good. The (E)-3-(aryl)-5-styryl-1,2,4-oxadiazoles exhibited a reduced spectrum of action, which were active against the bacterium P. aeruginosa and for the fungus C. utilis.

Synthesis, spectral analysis and pharmacological study of N'- substituted-2-(5-((2,4-dimethylphenoxy)methyl)-1,3,4-oxadiazol-2-ylthio)acetohydrazides

ABSTRACT A series of molecules bearing multiple functional groups were synthesized to study their antibiotic effect against Gram-positive and Gram-negative bacteria and lipoxygenase activity as well. 2,4-Dimethylcarbolic acid (1) was refluxed with ethyl 2-bromoacetate to synthesize ethyl 2-(2,4-dimethylphenoxy)acetate (2). Compound 2 was converted to the corresponding hydrazide 3, again on refluxing with hydrazine. The compound 5-((2,4-dimethylphenoxy)methyl)-1,3,4-oxadiazol-2-thiol (4) was synthesized by the reaction of 3 and CS2 in the presence of KOH. Compound 4 was further converted to the corresponding ester 5 and then 2-(5-((2,4-dimethylphenoxy)methyl)-1,3,4-oxadiazol-2-ylthio)acetohydrazide (6). The final molecules N'-substituted-2-(5-((2,4-dimethylphenoxy)methyl)-1,3,4-oxadiazol-2-ylthio)acetohydrazide, 8a-m, bearing ether, 1,3,4-oxadiazole, thioether, hydrazone and azomethine functional groups were synthesized by stirring the aryl carboxaldehydes 7a-m with 6 in methanol at room temperature. The depicted structures of all synthesized molecules were corroborated by IR, 1H-NMR and EIMS spectral data analysis. 8m and 8i showed substantial antibacterial activity and lipoxygenase inhibitory activity, respectively.

Seguridad y eficacia de ataluren en pacientes con diagnóstico de distrofia muscular de duchenne portadores de una mutación sin sentido en el gen de distrofina / Safety and efficacy of ataluren in patients diagnosed with duchenne muscular dystrophy who carry a nonsense mutation in the dystrophin gene

INTRODUCCIÓN: Antecedentes: El Instituto de Evaluación de Tecnologías en Salud e Investigación ha recibido la solicitud de evaluar el uso de Ataluren para su uso en Pacientes ambulantes mayores de 5 años con diagnóstico de distrofia muscular de Duchenne debida a una mutación sin sentido en el gen de la distrofina dentro del sistema de EsSalud, indicación actualmente no contemplada en el petitorio de medicamentos. Esta acción sigue lo estipulado en la Directiva N° 002-IETSI-ESSALUD-2015 y el objetivo final es determinar el estado del arte sobre la eficacia y seguridad de ataluren. Tecnología Sanitaria de Interés: Ataluren: La PTC124 (3-(5-(2-fluorofeni)-1, 2,4-oxadiazol-3-y1)-ácido benzoico), también conocida como Ataluren (TranslarnaTM) es una molécula pequeña de oxadiazol cuyo mecanismo de acción consiste en cominuar la traducción de ARNm sobre los codones de terminación prematuros causados por la mutación sin sentido, permitiendo la síntesis de distrofina completa y funcional. METODOLOGIA: Estrategia de Busqueda: Se realizó una búsqueda de la literatura con respecto a la eficacia y seguridad de Ataluren para el tratamiento de la DMD en las bases de datos de MEDLINE, EMBASE, CENTRAL, DARE y TRIPDATABASE. Se hizo una búsqueda adicional en www.clinicaltrials.gov, para poder identificar ensayos clínicos aún en elaboración o que no hayan sido publicados. Adicionalmente, se hizo una búsqueda dentro de la información generada por las principales instituciones internacionales oncológicas y agencias de tecnologías sanitarias que realizan revisiones sistemáticas (RS), evaluación de tecnologías sanitarias (ETS) y guías de práctica clínica (GPC). RESULTADOS:Sinopses de la Evidencia: Se realizó la búsqueda bibliográfica y de evidencia científica que sustente el uso de ataluren en DMD según la pregunta PICO establecida. Para el presente documento se seleccionó el siguiente cuerpo de evidencia que es resumido a continuación: Guías Clínicas: Se identificó una única guía práctica realizada en Colombia que hizo mención a este tratamiento. Evaluaciones de tecnología sanitaria: Se identificó una ETS del Reino Unido. Revisiones sistemáticas: No se identificaron revisiones sistemáticas. Estudios de calidad de vida: No se identificaron estudios que evaluaran calidad de vida. Ensayos clínicos: Se identificaron dos ECAs correspondientes a las fases 2a y fase 2 b. Ensayos clínicos en curso: se identificó el registro correspondiente a un estudio de fase III pendiente de publicar sus resultados. CONCLUSIONES: se evidencia que ataluren es un medicamento aún en estudio que no ha demostrado al momento ser diferente a placebo en el tratamiento de la DMD con mutación sin sentido. De hecho, la evidencia disponible que el ataluren no es mejor que el placebo en mejorar indicadores clínicos importantes en el manejo de esta enfermedad, como la DC6M, considerada como desenlace principal en enfermedades raras con compromiso neuromuscular. Ataluren tampoco mostró ser diferente al placebo en mejorar la calidad de vida de los pacientes, ni disminuye los tiempos para realizar tareas motoras como subir o bajar escalones, correr o caminar 10 metros y levantarse desde la posición supina. El Instituto de Evaluación de Tecnología en Salud e investigación ­ IETSI, no aprueba el uso de ataluren para el tratamiento de la DMD con mutación sin sentido del gen de la distrofina.

Synthesis of some novel enzyme inhibitors and antibacterial agents derived from 5-(1-(4-tosyl)piperidin-4-yl)-1, 3, 4-oxadiazol-2-thiol

ABSTRACT Keeping in mind the pharmacological importance of the 1,3,4-oxadiazole moiety, a series of new S-substituted derivatives, 5a-h, of 5-(1-(4-tosyl)piperidin-4-yl)-1,3,4-oxadiazol-2-thiol (3) were synthesized. The reaction of p-toluenesulfonyl chloride (a) and ethyl isonipecotate (b) produced ethyl 1-(4-tosyl)piperidin-4-carboxylate (1) which was further transformed into 1-(4-tosyl)piperidin-4-carbohydrazide (2) by hydrazine hydrate in methanol. Compound 2 was refluxed with CS2 in the presence of KOH to synthesize 5-(1-(4-tosyl)piperidin-4-yl)-1,3,4-oxadiazol-2-thiol (3). The desired compounds, 5a-h, were synthesized by stirring 3 with aralkyl halides, 4a-h, in DMF using NaH as an activator. The structures of synthesized compounds were elucidated by 1H-NMR, IR and EI-MS spectral studies. These compounds were further evaluated for enzyme inhibitory activity against lipoxygenase and alpha-glucosidase, along with antibacterial activity against Gram-negative and Gram-positive bacteria.

RESUMO Tendo em vista a importância farmacológica da porção 1,3,4-oxadiazol, sintetizou-se uma série de novos derivados S-substituídos, 5a-h, de 5-(1-(4-tosi)piperidin-4-il)-1,3,4-oxadiazol-2-tiol (3). A reação do cloreto de p-toluenossulfonila (a), com isonipecotato de (b) etila forneceu 1-(4-tosil)piperidin-4-carboxilato de metila (1), que foi, em seguida, transformado em 1-(4-tosil)piperidin-4-carbo-hidrazida (2) por reação com hidrato de hidrazina em metanol. O composto 2 foi submetido a refluxo com CS2 na presença de KOH para se obter 5-(1-(4-tosil)piperidin-4-il)-1,3,4-oxadiazol-2-tiol (3). Os compostos desejados, 5a-h, foram obtidos por agitação de 3 com haletos de aralquila, 4a-h, em DMF, na presença de NaH. As estruturas dos compostos sintetizados foram elucidadas através de análise dos espectros de 1H-MNR, IR e EI-MS. Estes compostos foram, ainda, avaliados quanto à inibição das enzimas lipoxigenase e alfa-glucosidase, juntamente com a atividade antibacteriana contra bactérias Gram positivas e Gram negativas.

Acute stress-induced antinociception is cGMP-dependent but heme oxygenase-independent

Endogenous carbon monoxide (CO), which is produced by the enzyme heme oxygenase (HO), participates as a neuromodulator in physiological processes such as thermoregulation and nociception by stimulating the formation of 3′,5′-cyclic guanosine monophosphate (cGMP). In particular, the acute physical restraint-induced fever of rats can be blocked by inhibiting the enzyme HO. A previous study reported that the HO-CO-cGMP pathway plays a key phasic antinociceptive role in modulating noninflammatory acute pain. Thus, this study evaluated the involvement of the HO-CO-cGMP pathway in antinociception induced by acute stress in male Wistar rats (250-300 g; n=8/group) using the analgesia index (AI) in the tail flick test. The results showed that antinociception induced by acute stress was not dependent on the HO-CO-cGMP pathway, as neither treatment with the HO inhibitor ZnDBPG nor heme-lysinate altered the AI. However, antinociception was dependent on cGMP activity because pretreatment with the guanylate cyclase inhibitor 1H-[1,2,4] oxadiazolo [4,3-a] quinoxaline-1-one (ODQ) blocked the increase in the AI induced by acute stress.

Participation of the NO/cGMP/K+ATP pathway in the antinociception induced by Walker tumor bearing in rats

Implantation of Walker 256 tumor decreases acute systemic inflammation in rats. Inflammatory hyperalgesia is one of the most important events of acute inflammation. The L-arginine/NO/cGMP/K+ATP pathway has been proposed as the mechanism of peripheral antinociception mediated by several drugs and physical exercise. The objective of this study was to investigate a possible involvement of the NO/cGMP/K+ATP pathway in antinociception induced in Walker 256 tumor-bearing male Wistar rats (180-220 g). The groups consisted of 5-6 animals. Mechanical inflammatory hypernociception was evaluated using an electronic version of the von Frey test. Walker tumor (4th and 7th day post-implantation) reduced prostaglandin E2- (PGE2, 400 ng/paw; 50 µL; intraplantar injection) and carrageenan-induced hypernociception (500 µg/paw; 100 µL; intraplantar injection). Walker tumor-induced analgesia was reversed (99.3% for carrageenan and 77.2% for PGE2) by a selective inhibitor of nitric oxide synthase (L-NAME; 90 mg/kg, ip) and L-arginine (200 mg/kg, ip), which prevented (80% for carrageenan and 65% for PGE2) the effect of L-NAME. Treatment with the soluble guanylyl cyclase inhibitor ODQ (100% for carrageenan and 95% for PGE2; 8 µg/paw) and the ATP-sensitive K+ channel (KATP) blocker glibenclamide (87.5% for carrageenan and 100% for PGE2; 160 µg/paw) reversed the antinociceptive effect of tumor bearing in a statistically significant manner (P < 0.05). The present study confirmed an intrinsic peripheral antinociceptive effect of Walker tumor bearing in rats. This antinociceptive effect seemed to be mediated by activation of the NO/cGMP pathway followed by the opening of KATP channels.

Atropine and ODQ antagonize tetanic fade induced by L-arginine in cats

Although it has been demonstrated that nitric oxide (NO) released from sodium nitrite induces tetanic fade in the cat neuromuscular preparations, the effect of L-arginine on tetanic fade and its origin induced by NO have not been studied in these preparations. Furthermore, atropine reduces tetanic fade induced by several cholinergic and anticholinergic drugs in these preparations, whose mechanism is suggested to be mediated by the interaction of acetylcholine with inhibitory presynaptic muscarinic receptors. The present study was conducted in cats to determine the effects of L-arginine alone or after pretreatment with atropine or 1H-[1,2,4]oxadiazole [4,3-a]quinoxalin-1-one (ODQ) on neuromuscular preparations indirectly stimulated at high frequency. Drugs were injected into the middle genicular artery. L-arginine (2 mg/kg) and S-nitroso-N-acetylpenicillamine (SNAP; 16 µg/kg) induced tetanic fade. The Nw-nitro-L-arginine (L-NOARG; 2 mg/kg) alone did not produce any effect, but reduced the tetanic fade induced by L-arginine. D-arginine (2 mg/kg) did not induce changes in tetanic fade. The tetanic fade induced by L-arginine or SNAP was reduced by previous injection of atropine (1.0 µg/kg) or ODQ (15 µg/kg). ODQ alone did not change tetanic fade. The data suggest that the NO-synthase-GC pathway participates in the L-arginine-induced tetanic fade in cat neuromuscular preparations. The tetanic fade induced by L-arginine probably depends on the action of NO at the presynaptic level. NO may stimulate guanylate cyclase increasing acetylcholine release and thereby stimulating presynaptic muscarinic receptors

Analgesic and anti-inflammatory effects of 3-3-(phenyl)-1, 2, 4-oxadiazol-5-yl propionic acid

Significant local analgesic and anti-inflammatory activity has been observed after oral administration of 3-[3-(phenyl)-1,2,4-oxadiazol-5-yl] propionic acid (POPA). Doses of 150 and 300 mg/kg body weight administered orally by gavage to adult (25-35 g) albino mice of both sexes can inhibit acetic acid-induced writhing by 31.0 and 49.5, respectively (mean +/- SEM writhing numbers during 20 min were 52.0 +/- 6.0 and 38.3 +/- 7.2 vs 75.8 +/- 6.6 for control group which received saline; N = 6). Carrageenin-induced inflammation in the female Wistar rat (200-250 g) can be reduced by 43.3 and 42.2 3 h after oral administration (gavage) of 75 and 150 mg/kg of POPA (mean +/- SEM, 30.0 +/- 1.3 and 30.6 +/- 2.4 vs 52.9 +/- 3.7 for control group which received saline; N = 5). In the hot plate test on adult albino mice (25-35 g) of both sexes, POPA (150 and 300 mg/kg, po) was totally ineffective (N = 10). Our results indicate that POPA appears to offer potential safety and efficacy as a local analgesic and anti-inflammatory agent with no central nervous system involvement

Effectos de la nitroglicerina y SIN-1 sobre la frecuencia espontanea y los niveles de GMPe en la auricula aislada de rata. / Effects of nitroglycerin and SIN-1 on spontaneous rate and cGMP levels in the isolated rat atria

En auriculas aisladas de rata latiendo espontaneamente se estudiaron los efectos sobre la frecuencia espontanea y el contenido de GMPc intracelular del SIN-1 y la nitroglicerina. La frecuencia basal de las preparaciones fue de 254 +/- 5 lat. m(-1) en el grupo de experimentos con SIN-1 y de 276 +/- 8 lat.m(-1) en el nitroglicerina. La adminstracion de SIN-1 o nitroglicerina en un rango de concentraciones de 10(-11) a 10(-4)M no produjo cambios significativos de la frecuencia, siendo los valores de 253 +/- 9 lat.m(-1) y de 277+/- 8 lat. m(-1) luego de administrar la ultima dosis de SIN-1 o nitroglicerina respectivamente. Las determinaciones de GMPc indicaron que el contenido de este nucleotico aumento desde un valor control de 46.98 +/- 12.1 fmoles. mg(-1) a 86.4 +/- 3.2 fmoles. mg(-1) con 10(-5)M de SIN-1 y a 107.6 +/- 12.2 fmoles. mg(-1) con 10(-5)M de nitroglicerina. Los resultados obtenidos permiten concluir que, a pesar del incremento en los niveles de GMPc, el cronotropismo no se altera, tal vez como expresion de desacople entre la guanilato ciclasa estimulada por estos vasodilatadores y la proteina quinasa GMPc dependiente