Evaluación de la toxicidad de chalconas sintéticas con potencial anti-Leishmania en ratones BALB/c / Toxicity assessment of synthetic chalcones with antileishmanial potential in BALB/c mice

RESUMEN Objetivo: Evaluar la toxicidad de tres chalconas sintéticas administradas por vía intraperitoneal en ratones BALB/c. Materiales y métodos: La dosis letal media (DL50) se estimó por el método Up-and-Down de Dixon. La toxicidad subcrónica de las chalconas se evaluó a 20 y 40 mg/kg por 21 días. Se evaluó el efecto tóxico a nivel de comportamiento, fisiológico, bioquímico e histológico. Resultados: La chalcona 43 generó moco en las heces, daño visceral (hígado) y alteración en el coeficiente de órganos (riñón, p = 0,037 y cerebro, p = 0,008) en comparación con el grupo control. Además, en el análisis histológico se observó que esta chalcona produjo edema, inflamación y necrosis en los órganos evaluados, aunque no hubo diferencia significativa con el control. Todos los parámetros bioquímicos no difirieron significativamente entre los grupos de tratamiento a dosis de 40 mg/kg y el control. Conclusiones: La DL50 para las tres chalconas fue superior a 550 mg/kg de peso corporal. Las chalconas 40 y 42 son relativamente no tóxicas. Ambas pueden considerarse seguras para la aplicación vía intraperitoneal en ratones BALB/c y, en consecuencia, son posibles candidatas para ser usadas en el tratamiento contra las leishmaniosis.

ABSTRACT Objective: To evaluate the toxicity of three synthetic chalcones administered intraperitoneally to BALB/c mice. Materials and methods: The median lethal dose (LD50) was estimated by Dixon's Up-and-Down method. Subchronic toxicity of chalcones was evaluated at 20 and 40 mg/kg for 21 days. Behavioral, physiological, biochemical, and histological toxic effects were evaluated. Results: Chalcone 43 produced mucus in feces, visceral damage (liver) and alterations in organ coefficient (kidney, p = 0.037 and brain, p = 0.008) when compared to the control group. In addition, histological analysis showed that this chalcone produced edema, inflammation and necrosis in the evaluated organs, although there was no significant difference with the control. None of the biochemical parameters differed significantly between the treatment groups at 40 mg/kg dose and the control. Conclusions: The LD50 for all three chalcones was greater than 550 mg/kg of body weight. Chalcones 40 and 42 were found to be relatively non-toxic. Both can be considered safe for intraperitoneal application in BALB/c mice and, consequently, are potential candidates for use in the treatment of leishmaniasis.

Hydroxysafflor yellow A acutely attenuates blood-brain barrier permeability, oxidative stress, inflammation and apoptosis in traumatic brain injury in rats1

Abstract Purpose: To investigate the therapeutic benefits of Hydroxysafflor yellow A (HSYA) on blood-brain barrier (BBB) vulnerability after traumatic brain injury (TBI) and identify its potential action of mechanisms on TBIinduced injuries. Methods: The rat TBI model was performed by using a controlled cortical impact device. The BBB permeability induced by TBI was measured through Evans Blue dye superflux and western blotting or polymerase chain reaction (PCR) for tight junctional proteins (TJPs). The post-TBI changes in oxidative stress markers, inflammatory response and neuron apoptosis in brain tissue were also tested. Results: Herein, the results showed that HSYA acutely attenuated BBB permeability via increasing the production of the TJPs, including occludin, claudin-1 and zonula occludens protein 24 h after TBI. Additionally, HSYA could suppress the secretion of proinflammatory factors, such as interleukin-1β, interleukin-6, and tumor necrosis factor-α (IL-1β, IL-6, and TNF-α), and also concurrently down-regulate the expression of inflammation-related Toll-like receptor 4/nuclear factor kappa-B (TLR4/NF-kB) protein. These HSYA challenged changes were accompanied by the decreased TBI induced oxidative stress markers and inhibited the expression of apoptosis proteins Bax, caspase-3 and caspase-9. Conclusions: Taken together, all findings suggested that HSYA (30 mg/kg) are against TBI through improving the integrity in BBB, which are associated with the antioxidant, anti-inflammation and antiapoptosis via the probable mechanism of down-regulation of the TLR4/NF-kB pathway, and its in-detail protective mechanisms are under study.

Evaluation of direct pulp capping with a synthetic chalcone: a preliminary histological study / Evaluación del recubrimiento pulpar directo con una chalcona sintética: estudio histológico preliminar

The aim of this study is to evaluate the action of the synthetic chalcone 1-phenyl-3-(4-chlorophenyl)-2-propen-1-one to induce pulp healing in rats. Material and Methods: Sixty lower first molars of male Wistar rats were divided into 3 groups (n=20): control (no treatment); calcium hydroxide and chalcone. After relative isolation, the cavities were prepared using a sterile low-speed » round dental bur. After controlling the hemorrhaging, all the pulp exposures were capped with the capping material, by groups. The cavities were sealed with glass ionomer cement and the repair process was assessed at 21 days of procedure. The data were statistically analyzed using the Fisher exact test (p<0.05). Results: Moderate inflammation was observed in all the experimental groups and significant (p<0.05) reparative dentin (tertiary) formation in the calcium hydroxide and chalcone groups. The chalcone group showed dentinal tubules and a low number of cellular inclusions (p<0.05). Conclusion: The chalcone used in this study indicates potential as an inducer of reparative dentine (tertiary) in a rat model...

El objetivo de este estudio es evaluar la acción de la chalcona sintética 1-fenil-3- (4-clorofenil) -2-propen-1-ona para inducir la reparación de la pulpa dentaria en ratas. Materiales y métodos: Sesenta primeros molares inferiores de ratas Wistar machos se dividieron en 3 grupos (n = 20): control (sin tratamiento); hidróxido de calcio y chalcona. Después del aislamiento relativo, las cavidades se prepararon usando una fresa dental redonda de » estéril a baja velocidad. Después de controlar la hemorragia, todas las exposiciones pulpares se taparon con el material de recubrimiento de acuerdo con los grupos del experimiento. Las cavidades fueron selladas con cemento de ionómero de vidrio y el proceso de reparación se evaluó a los 21 días del procedimiento. Los datos fueron analizados estadísticamente mediante la prueba exacta de Fisher (p<0,05). Resultados: Se observó inflamación moderada en todos los grupos experimentales y significativa (p <0,05) formación de dentina reparadora (terciaria) en los grupos de hidróxido de cálcio y chalcona. El grupo de chalcona mostró túbulos dentinarios y un bajo número de inclusiones celulares (p <0,05). Conclusión: La chalcona utilizada en este estudio indica potencial como un inductor de la dentina reparadora (terciaria) en ratas...

Presencia del elemento genético transportable dTdic1 en Dianthus caryophyllus con flores variegadas y no variegadas / Presence of the transposable genetic element dTdic1 in Dianthus caryophyllus with variegated and no variegated flowers

El objetivo de este trabajo era la búsqueda del EGT (Elemento Genético Transponible) dTdic1 que ha sido asociado con la variegación del color de las flores de clavel y su relación con dos genes que codifican para enzimas involucradas en la biosíntesis de antocianinas, Chalcona isomerasa (CHI) y Dihidroflavonol reductasa (DFR). Su presencia y expresión se evaluó en siete genotipos con flores variegadas (líneas híbridas) y en cuatro genotipos de flores no variegadas (una línea híbrida y tres cultivares comerciales). Un alto número (indefinido) de copias del elemento dTdic1 se detectó en todas las líneas variegadas y no variegadas. En consecuencia, la sola presencia de este EGT no pudo asociarse directamente con la variegación de los pigmentos florales de flores de clavel. Adicionalmente, dTdic1 se encontró interrumpiendo el gen CHI en cuatro genotipos variegados y uno no variegado. No se observó evidencia de inserción de dTdic1 en el gen DFR en ninguno de los genotipos.

The objective of this work was to search for the EGT (Transposable Genetic Element) dTdic1 that has been associated with color variegation of carnation flowers and its relationship with two genes that code for enzymes involved in the synthesis of anthocyanins, Chalcona isomerase (CHI) and Dihidroflavonol reductase (DFR). Its presence and expression was evaluated in seven genotypes of variegated flowers and four no variegated flower genotypes (one hybrid line and three commercial cultivars). A high number of copies (undefined) of copies of the dTdic1 element was detected in variegaated and no variegated lines. Therefore, the main presence of this EGT was not associated directly with variegation of floral pigments. Additionally, dTdic1 was found interrupting the CHI gene in four variegated and one no variegated phenotypes. No evidence was observed of insertion of dTdic1 in the DFR gene in any of the genotypes.

In vitro anti-inflammatory, cytotoxic and antioxidant activities of boesenbergin A, a chalcone isolated from Boesenbergia rotunda (L.) (fingerroot)

The current in vitro study was designed to investigate the anti-inflammatory, cytotoxic and antioxidant activities of boesenbergin A (BA), a chalcone derivative of known structure isolated from Boesenbergia rotunda. Human hepatocellular carcinoma (HepG2), colon adenocarcinoma (HT-29), non-small cell lung cancer (A549), prostate adenocarcinoma (PC3), and normal hepatic cells (WRL-68) were used to evaluate the cytotoxicity of BA using the MTT assay. The antioxidant activity of BA was assessed by the ORAC assay and compared to quercetin as a standard reference antioxidant. ORAC results are reported as the equivalent concentration of Trolox that produces the same level of antioxidant activity as the sample tested at 20 µg/mL. The toxic effect of BA on different cell types, reported as IC50, yielded 20.22 ± 3.15, 10.69 ± 2.64, 20.31 ± 1.34, 94.10 ± 1.19, and 9.324 ± 0.24 µg/mL for A549, PC3, HepG2, HT-29, and WRL-68, respectively. BA displayed considerable antioxidant activity, when the results of ORAC assay were reported as Trolox equivalents. BA (20 µg/mL) and quercetin (5 µg/mL) were equivalent to a Trolox concentration of 11.91 ± 0.23 and 160.32 ± 2.75 µM, respectively. Moreover, the anti-inflammatory activity of BA was significant at 12.5 to 50 µM and without any significant cytotoxicity for the murine macrophage cell line RAW 264.7 at 50 µM. The significant biological activities observed in this study indicated that BA may be one of the agents responsible for the reported biological activities of B. rotunda crude extract.

Actividad del (2E)-3-(2, 3-dimetoxifenil)-1-(4-metilfenil) prop-2-en-1-ona en presencia del poli(ácido maleico-co-2-vinil-pirrolidona) sobre un aislamiento clínico de Staphylococcus aureus / Activity of (2E)-3-(2, 3-dimetoxifenil)-1-(4-metilfenil) prop-2-en-1-ona in the presence of poli(maleic acid-co-2-vinyl-pyrrolidone)

Introducción: debido a la problemática actual de fármaco-resistencia hacia los antibióticos b-lactámicos, se ha hecho necesario, en busca de una solución, trabajar con nuevas moléculas con potencial farmacológico, así como utilizar novedosos sistemas poliméricos como matrices o excipientes farmacéuticos. Objetivo: evaluar la actividad antibiótica de la ampicilina, combinada con un compuesto sintético de tipo chalcona, denominado (2E)-3-(2,3-dimetoxifenil)-1-(4-metilfenil)prop-2-en- 1-ona, sobre un aislamiento clínico de Staphylococcus aureus resistente a penicilinas, en presencia de una matriz polimérica hidrosoluble denominada poli(ácido maleico-co-2-vinilpirrolidona). Materiales y métodos: el compuesto sintético y la matriz polimérica se obtuvieron por métodos descritos en la literatura. Se usó un aislamiento clínico de Staphylococcus aureus resistente a penicilinas y se hicieron ensayos de actividad antibiótica por la técnica de macrodilución en caldo, de la cual se obtuvieron las concentraciones inhibidoras mínimas de los compuestos evaluados. Resultados: la mezcla ampicilina-chalcona muestra un efecto antibiótico menor que el de su referente ampicilina-sulbactam. No obstante, cuando se utiliza la matriz polimérica en combinación con la ampicilina-chalcona se aprecia un incremento significativo de la actividad antibiótica, evidenciado en que la concentración inhibidora mínima es la mitad de la del referente comercial.

Introduction: Due to the current problem of resistance to b-lactam antibiotics, it has become necessary, in search of a solution, to work with new molecules with pharmacological potential, and to use novel polymeric systems as matrices or pharmaceutical excipients. Objective: To evaluate the antibiotic activity of ampicillin combined with a synthetic chalcone-type compound, the (2E)-3-(2,3-dimethoxyphenyl)-1-(4- methylphenyl) prop-2-en-1-one, on a clinical isolate of penicillin-resistant Staphylococcus aureus in the presence of a water soluble polymer matrix known as poly(maleic acid-co-2-vinyl-pyrrolidone). Materials and methods: The synthetic compound and the polymeric matrix were obtained by previously described methods. Tests for antibiotic activity against the strain of penicillin-resistant Staphylococcus aureus were done by the broth dilution technique which provided the minimal inhibitory concentrations of the compounds tested. Results: The chalcone-ampicillin mix shows lesser antibiotic effect than the ampicillin-sulbactam used as referent. However, when such mix is combined with the polymer matrix, antibiotic activity significantly increases as evidenced by decrease in the minimal inhibitory concentration with respect to the ampicillin-sulbactam referent.

Bacteriostatic action of synthetic polyhydroxylated chalcones against Escherichia coli

In previous work the bacteriostatic action of trihydroxylated chalcones against Staphylococcus aureus ATCC 25 923 was investigated. In this work the action of 2',4',2-(OH)3-chalcone, 2',4',3-(OH)3-chalcone and 2',4',4-(OH)3-chalcone against Escherichia coli ATCC 25 922 was evaluated. Growth kinetic curves of E. coli were made in nutritive broth added with increasing drug concentrations. The specific growth rates of the microorganisms were calculated by a kinetic turbidimetric method, which was previously probed and the minimal inhibitory concentrations (MIC's) were evaluated by a mechanism of action proposed. The MICs of 2',4',3-(OH)3-chalcone and 2',4',2-(OH)3-chalcone were 46 microg/ml and 122 microg/ml, respectively. The 2',4',4-(OH)3-chalcone was inactive. The MIC value of 2',4',3-(OH)3-chalcone (46 microg/ml), more active than 2',3-(OH)2-chalcone (72.2 microg/ml) may be due to the introduction of an electron donating group (-OH) at position 4' in the aromatic A-ring, which activates the region that includes the 2'-hydroxyl neighbor group and the alpha,beta-unsaturated carbonyl group.

Análise clínica e morfológica da conjuntivite alérgica induzida por ovalbumina e tratada com chalcona em cobaias / Clinical and morphologic analysis of allergic conjunctivitis induced by ovalbumin and treated with chalcona in guinea pigs

OBJETIVO: Verificar, do ponto de vista clínico e morfológico, o efeito da chalcona na conjuntivite alérgica induzida por ovalbumina em cobaias. MÉTODOS: Utilizaram-se 54 cobaias, albinos, machos pesando aproximadamente 400 g. Os animais foram sensibilizados por injeção intraperitoneal de ovalbumina suspensa em solução adjuvante completa de Freund. Posteriormente, a conjuntivite alérgica foi induzida por instilação de ovalbumina no saco conjuntival do olho direito. Os animais foram distribuídos em 3 grupos, conforme o tratamento proposto: chalcona, corticóide e salina. A avaliação clínica foi realizada com 5, 10 e 40 min, 7 e 24 h da indução e diariamente até o dia 7 da indução. A avaliação morfológica consistiu em avaliar edema, necrose, vascularização e exocitose nos dias 1, 3 e 7 da indução. RESULTADOS: Em todos os grupos a resposta inflamatória foi mais intensa 24 h após a indução. No grupo chalcona evidenciou-se menos sinais inflamatórios que no grupo salina. O grupo corticóide apresentou menos sinais inflamatórios quando comparados aos grupos chalcona e controle. A análise morfológica evidenciou-se que os grupos chalcona e corticóide apresentaram efeitos terapêuticos semelhantes. CONCLUSÃO: A chalcona teve efeito terapêutico na conjuntivite alérgica induzida por ovalbumina.

A new member of the chalcone synthase (CHS) family in sugarcane

Seqüências do banco de dados SUCEST foram analisadas baseado em suas identidades com genes relacionados que codificam enzimas chalcone sintase (CHS). A seqüência da proteína CHS de sorgo (gi-12229613), foi usada para a busca de seqüências no banco de dados do SUCEST, que foram mais similares à CHS. Baseado na similaridade das seqüências de aminoácidos deduzidas, quatorze conjuntos formados por 121 seqüências, foram divididos em dois grupos. O primeiro grupo é mais similar à CHS de sorgo (EC 2.3.1.74) e apresenta a seqüência consenso do sítio ativo de chalcone e stilbene sintase. Análises da expressäo gênica, baseada no número de seqüências de uma dada biblioteca presente em cada grupo, indicaram que neste caso, a maioria das seqüências säo de bibliotecas preparadas de raiz e flores de cana-de-açúcar. O segundo grupo é mais similar à seqüência de aminoácidos deduzida de uma proteína, näo caracterizada, induzida por patógeno (PIl, gi-9855801-) do banco de dados de EST de Sorghum bicolor. Estas duas seqüências de proteínas säo 90 por cento idênticas e tem duas mudanças de aminoácidos no consenso padräo de chalcone e stilbene sintase, e conservam o resíduo de cisteína na posiçäo do sítio ativo. Esta EST näo foi associada a chalcone sintase antes, e apresenta diferenças na seqüência consenso da CHS previamente descrita de sorgo. A maioria das seqüências do segundo grupo säo de bibliotecas de cana-de-açúcar preparadas de raiz e plantas infectadas com Herbaspirillum rubrisubalbicans e Gluconacetobacter diazotroficans. Os resultados indicam que nós identificamos uma chalcone sintase, tal como a encontrada no banco de cDNA de sorgo em uma biblioteca induzida por patógeno, expressa em plantas de cana-de-açúcar, e que ambas as proteínas säo novos membros da super família chalcone e stilbene sintase.

Structure-biological activity relationship of synthetic trihydroxilated chalcones

The bacteriostatic activity of 2',4',2'-trihydroxychalcone; 2',4',3'-trihydroxychalcone and 2',4',4'-trihydroxychalcone, prepared by condensation of 2,4-dihydroxyacetophenone and benzaldehyde substituted, against "Staphylococcus aureus" ATCC 25923 was assayed by agar plate method. The three compounds presented important inhibition halos. In order to elucidate structure-activity relationships, the minimal inhibitory concentrations against "S. aureus"were determined by the broth dilution method and the results obtained were compared to that of 2',4'-(OH)2>MIC 2',4',4'-(OH)3>>MIC 2',4',2-(OH)3. these results showed that the introduction of an electron donating group (-OH) in the aromatic B-ring causes an increase in bioactivity, and that the intensity of action depends on the position of the OH substitute.

Actividad bacteriostatica de 2', 4'- dihidroxi 3'-metoxichalcona / Bacteriostatic activity of 2', 4'- dihydroxy 3'-methoxychalcone

Continuando la realización de ensayos microbiológicos con sustancias naturales de propiedades desconocidas, se investigó y cuantificó el efecto ejercido por 2',4' -dihidroxi-3' -metoxichalcona (aislada de la Zuccagnia Punctata Cav., San Luis, Argentina), sobre el crecimiento de cepas de Staphylococcus aureus y Escherichia coli. Utilizando un método cinétido turbidimétrico se determinó la CMI (58,6 microng/ml) y se interpretó la actividad bacteriostática del compuesto mediante un mecanismo de inhibición que implica la complejación de metales indispensables para el metabolismo del microorganismo

Cinética de la acción bacteriostática de chalconas naturales y de síntesis sobre una cepa de Staphylococcus aureus / Kinetics of the bacteriostatic action of synthetic and natural chalcones on a Staphylococcus aureus strain

Se estudió la acción bacteriostática ejercida por chalconas naturales (2',4'-dihidroxichalcona y 2'-hidroxi-4'-metoxichalcona) y de síntesis (chalcona, 2'-hidroxicalcona, 2'4-dihidroxichalcona y 2'-hidroxi-4-metoxichalcona) sobre Staphylococcus aureus (cepa ATCC 25 923). Se determinó la influencia de la concentración de la natureza y posición de los sustituyentes de las drogas empleadas sobre la tasa de crecimiento específica del germen. Los ensayos cualitativos se hicieron en placas de agar nutritivo y mostraron la acción inhibitoria de chalcona y sus derivados dihidroxilados. Los resultados obtenidos distiguen el potente efecto bacteriostático de 2',4'-dihidroxichalcona y 2',4'-dihidrochalcona que en bajas concentraciones provocaron inhibición total en el crecimiento del microorganismo, de las otras chalconas estudiadas que solamente disminuyeron la tasa de crecimiento específica del germe hasta un valor límite. Se observa que la presencia de un grupo oxihidrilo en el anillo A o B de la 2'-hidroxichalcona potencia su actividad bacteriostática siendo este efecto más pronunciado en la posición 4'(anillo A) respecto de la posición 4 (anillo B). La introducción de un grupo metoxilo en la estructura de la 2'-hidroxichalcona produce un decrecimiento de su potencia inhibitoria