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Toxoplasmosis is a parasitic disease caused by the protozoan Toxoplasma gondii that is highly prevalent worldwide. Although the infection is asymptomatic in immunocompetent individuals, it severely affects immunocompromised individuals, causing conditions such as encephalitis, myocarditis, or pneumonitis. The limited therapeutic efficacy of drugs currently used to treat toxoplasmosis has prompted the search for new therapeutic alternatives. The aim of this study was to determine the anti-Toxoplasma activity of extracts obtained from two species of the genus Tabebuia. Twenty-six extracts, 12 obtained from Tabebuia chrysantha and 14 from Tabebuia rosea, were evaluated by a colorimetric technique using the RH strain of T. gondii that expresses ß-galactosidase. Additionally, the activity of the promising extracts and their active compounds was evaluated by flow cytometry. ß-amyrin was isolated from the chloroform extract obtained from the leaves of T. rosea and displayed important anti-Toxoplasma activity. The results show that natural products are an important source of new molecules with considerable biological and/or pharmacological activity.

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Obesity is characterized by the excessive accumulation of fat, which triggers a low-grade chronic inflammatory process. Currently, the search for compounds with anti-obesogenic effects that help reduce body weight, as well as associated comorbidities, continues. Among this group of compounds are plant extracts and flavonoids with a great diversity of action mechanisms associated with their beneficial effects, such as anti-inflammatory effects and/or as signaling molecules. In the bark of Tabebuia rosea tree, there are different classes of metabolites with anti-inflammatory properties, such as quercetin. Therefore, the present work studied the effect of the ethanolic extract of T. rosea and quercetin on the mRNA of inflammation markers in obesity compared to the drugs currently used. Total RNA was extracted from epididymal adipose tissue of high-fat diet-induced obese Wistar rats treated with orlistat, phentermine, T. rosea extract, and quercetin. The rats treated with T. rosea and quercetin showed 36 and 31% reductions in body weight compared to the obese control, and they likewise inhibited pro-inflammatory molecules: Il6, Il1b, Il18, Lep, Hif1a, and Nfkb1 without modifying the expression of Socs1 and Socs3. Additionally, only T. rosea overexpressed Lipe. Both T. rosea and quercetin led to a reduction in the expression of pro-inflammatory genes, modifying signaling pathways, which led to the regulation of the obesity-inflammation state.

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Background: A large number of chemical compounds exert their antioxidant effects by activation of key transcriptional regulatory mechanisms, such as the transcription factor Nrf2. The aim of this study was to evaluate the activation of the Keap1-Nrf2 pathway by both the n-butanol extract obtained from the inner bark of Tabebuia rosea (Bertol) DC and specioside isolated from this extract. Methods: The antioxidant activity of the extract and specioside isolated from the inner bark of T. rosea were evaluated using the oxygen radical absorbance capacity (ORAC) and the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH) techniques, whereas their effects on the viability of HepG2 cells was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. The effects of the compound and the extract on activating the Keap1-Nrf2 pathway were evaluated using a Nrf2 Transcription Factor Assay kit. Induction of the Nrf2-mediated antioxidant response genes HMOX-1 and NQO1 was evaluated by real-time PCR. The protective effects against H 2O 2-induced oxidative stress in HepG2 cells was determined as the percent protection using the MTT method. Results: Both the n-butanol extract and specioside exhibited activity at low concentrations without affecting cellular viability, since the cell viability was greater than 80% after 24 hours of exposure at each tested concentration. In addition, Nrf2 dissociated from Keap1 after treatment with the n-butanol extract at a concentration of 0.25 µg/mL after 4 hours of exposure. An increase in the Nrf2 level in the cytoplasm after 4 hours of exposure to 2 µM specioside was observed. Nrf2 levels stabilized in the nucleus 12 hours after stimulation with both specioside and the extract. After 6 hours of stimulation, both the extract and specioside induced the expression of HMOX-1 and NQO1. Conclusion: The n-butanol extract from the inner bark of T. rosea and specioside produced protective effects against H 2O 2-induced oxidative stress in HepG2 cells.

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Introducción. Las susceptibilidades de las plantaciones al ataque de organismos dañinos pueden ocasionar efectos nocivos para su desarrollo, cuando se considera que el nivel de daños ocasionado no se puede tolerar, es indispensable determinar acertadamente la naturaleza del agente causal, sea éste tipo biótico o abiótico; la acertada determinación del agente de un problema fitosanitario en un vivero o plantaciones forestale, se fundamenta en un análisis detallado de los factores que la pueden estar afectando. Tabebuia rosea o Guayacán rosado es una especie forestal nativa de amplia aceptación en el mercado, que presenta durante su etapa de vivero, limitantes en las fases de germinación, emergencia y sobrevivencia, por lo anterior el objetivo de esta investigación era la de Identificar morfológicamente los posibles agentes patógenos asociados a Tabebuia rosea en etapa de vivero y comprobar su patogenicidad. Metodología. Se tomaron plántulas de vivero, las cuales se les realizo un análisis de los signos y los síntomas para el aislamiento y siembra de zonas afectadas en agar papa dextrosa. En el cultivo mixto se identificó los posibles agentes patógenos, los cuales fueron sembrados para obtener cultivos puros, y utilizados en la prueba de patogenicidad, para la inoculación de las estructuras sanas (hojas, peciolos y tallos) y su respectivo control. Resultados. Se identificaron tres géneros de hongos Colletotrichum, Mucor, y Candida, y un género de nematodo denominado Meloidogyne. La prueba de patogenicidad para Colletotrichum y Candida mostraron relaciones significativas en el proceso de infección principalmente en estructuras foliares. Se concluye en este trabajo dos nuevos posibles géneros patógenos para Tabebuia rosea evidenciados en la prueba de patogenicidad. Y se corrobora que el género Meloidogyne es un patógeno severo en el guayacán rosado que ocasiona anomalías morfológicas en la raíz; cabe resaltar que es el primer reporte para el departamento de Risaralda

Introduction. The susceptibilities of plantations to attack by harmful organisms can cause harmful effects for their development, when it is considered that the level of damage caused cannot be tolerated, it is essential to correctly determine the nature of the causal agent, be it biotic or abiotic; The correct determination of the agent of a phytosanitary problem in a nursery or forest plantations is based on a detailed analysis of the factors that may be affecting it. Tabebuia rosea or pink Guayacán is a native forest species widely accepted in the market, which presents, during its nursery stage, limitations in the germination, emergence and survival phases, therefore the objective of this research was to morphologically identify the possible pathogens associated with Tabebuia rosea in the nursery stage and check its pathogenicity. Methodology. Nursery seedlings were taken, which were analyzed for signs and symptoms for the isolation and sowing of affected areas on potato dextrose agar. In the mixed culture, possible pathogens were identified, which were sown to obtain pure cultures, and used in the pathogenicity test, for the inoculation of healthy structures (leaves, petioles and stems) and their respective control. Results. Three fungal genera Colletotrichum, Mucor, and Candida, and a nematode genus named Meloidogyne were identified. The pathogenicity test for Colletotrichum and Candida showed significant relationships in the infection process mainly in leaf structures. Two new possible pathogenic genera for Tabebuia rosea evidenced in the pathogenicity test are concluded in this work. And it is corroborated that the genus Meloidogyne is a severe pathogen in the pink guayacán that causes morphological anomalies in the root; It should be noted that it is the first report for the department of Risaralda

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Background: Several ethnobotanical and ethnopharmacological studies have shown the therapeutic potential of plants from the genus Tabebuia, which have long been used in traditional medicine in rural areas of South America, for the treatment of several human diseases. This study aimed to evaluate the Nrf2-mediated antioxidant activity of the inner bark extracts obtained from Tabebuia rosea and Tabebuia chrysantha. Methods: The antioxidant activity of extracts obtained from the inner bark of T. rosea and T. chrysantha was evaluated using the Oxygen radical absorbance capacity (ORAC) technique. The effect of extracts on the viability of HepG2 cells was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method. The translocation of Nrf2 to the nucleus after exposure of HepG2 cells to the extracts and controls (α-lipoic acid, curcumin and hydrogen peroxide) was evaluated using the Nrf2 transcription factor kit. Induction of the Nrf2-mediated antioxidant response gene ( NQO1) was evaluated by real-time PCR. Results: The ethyl acetate extract obtained from both species displayed the highest ORAC activity (12,523 and 6,325 µmoles Eq Trolox/g extract). In addition, the extracts had the ability to activate and to translocate Nrf2 to the nucleus, as well as to induce the expression of NQO1. Conclusion: These results indicate that the ethyl acetate extracts obtained from the inner bark of T. chrysantha and T. rosea have an important antioxidant effect mediated by Nrf2 activation, and could be used as a new source of natural antioxidants.

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BACKGROUND AND AIMS: Conifers dominated wet lowland tropical forests 100 million years ago (MYA). With a few exceptions in the Podocarpaceae and Araucariaceae, conifers are now absent from this biome. This shift to angiosperm dominance also coincided with a large decline in atmospheric CO2 concentration (ca). We compared growth and physiological performance of two lowland tropical angiosperms and conifers at ca levels representing pre-industrial (280 ppm), ambient (400 ppm) and Eocene (800 ppm) conditions to explore how differences in ca affect the growth and water-use efficiency (WUE) of seedlings from these groups. METHODS: Two conifers (Araucaria heterophylla and Podocarpus guatemalensis) and two angiosperm trees (Tabebuia rosea and Chrysophyllum cainito) were grown in climate-controlled glasshouses in Panama. Growth, photosynthetic rates, nutrient uptake, and nutrient use and water-use efficiencies were measured. KEY RESULTS: Podocarpus seedlings showed a stronger (66 %) increase in relative growth rate with increasing ca relative to Araucaria (19 %) and the angiosperms (no growth enhancement). The response of Podocarpus is consistent with expectations for species with conservative growth traits and low mesophyll diffusion conductance. While previous work has shown limited stomatal response of conifers to ca, we found that the two conifers had significantly greater increases in leaf and whole-plant WUE than the angiosperms, reflecting increased photosynthetic rate and reduced stomatal conductance. Foliar nitrogen isotope ratios (δ15N) and soil nitrate concentrations indicated a preference in Podocarpus for ammonium over nitrate, which may impact nitrogen uptake relative to nitrate assimilators under high ca SIGNIFICANCE: Podocarps colonized tropical forests after angiosperms achieved dominance and are now restricted to infertile soils. Although limited to a single species, our data suggest that higher ca may have been favourable for podocarp colonization of tropical South America 60 MYA, while plasticity in photosynthetic capacity and WUE may help account for their continued persistence under large changes in ca since the Eocene.

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The ecological restoration strategies for highly threatened ecosystems such as the tropical dry forest, depend on the knowledge of limiting factors of biological processes for the different species. Some of these include aspects such as germination and seed longevity of typical species present in those forests. In this study, we evaluated the effect of light and temperature on seed germination of two Fabaceae (Samanea saman and Jacaranda caucana) and two Bignoniaceae (Pithecellobium dulce and Tabebuia rosea) species having potential use in restoration, and we analyzed the seed storage behavior of these species for a three months period. To study the light effect, four levels of light quality on seeds were used (photoperiod of 12 hours of white light, darkness and light enriched in red and far-red, both for an hour each day), and we combined them with three levels of alternated temperatures (20/25, 20/30 and 25/30°C-16/8h). For the storage behavior, two levels of seed moisture content particular for each species were used (low: 3.5-6.1% and high: 8.3-13.8%), with three storage temperatures (20, 5 and -20°C) and two storage times (one and three months). The criterion for germination was radicle emergence which was measured in four replicates per treatment, and was expressed as percentage of germination (PG). There were significant differences in germination of Samanea saman and Jacaranda caucana among light and temperature treatments, with the lowest value in darkness treatments, whereas germination of Pithecellobium dulce and Tabebuia rosea did not differ between treatments (PG>90%). The most suitable temperature regime to promote germination in all species was 25/30°C. These four species showed an orthodox seed storage behavior. We concluded that seeds of P. dulce, J. caucana and T. rosea did not have an apparent influence of all light conditions tested in their germination response, which might confer advantages in colonization and establishment processes, while S. saman did not germinate well in darkness. We suggest the use of seeds of P. dulce, J. caucana and T. rosea in ecological restoration processes, due to their tolerance and germination under a wide range of temperature and light conditions. Futhermore, seeds of S. saman might be used in open areas such as forest gaps.

Las estrategias de restauración ecológica en ecosistemas altamente amenazados como el bosque seco tropical, dependen del conocimiento de factores limitantes de procesos biológicos, como la germinación y la longevidad de semillas de especies típicas de los mismos. En este estudio se evaluó el efecto de la luz y la temperatura en la germinación de semillas de dos especies de Fabaceae y dos de Bignoniaceae potencialmente útiles para restauración, y se determinó su comportamiento en el almacenamiento. Para el primer objetivo, se utilizaron cuatro niveles de calidad lumínica (fotoperiodo con 12 horas de luz, oscuridad y estímulos de luz enriquecida en rojo y luz enriquecida en rojo lejano, ambas por una hora), combinados con tres niveles de temperaturas alternadas (20/25, 20/30 y 25/30°C - 16/8h). Para el segundo objetivo, se utilizaron dos niveles de contenido de humedad de las semillas, con tres niveles de temperatura de almacenamiento (20, 5 y -20°C) y dos tiempos de almacenamiento (1 y 3 meses). La variable de respuesta para ambos experimentos fue el número de semillas germinadas, expresado en porcentaje (PG). Samanea saman y Jacaranda caucana presentaron un PG significativamente diferente entre los tratamientos lumínicos, con el valor menor en la oscuridad, mientras Pithecellobium dulce y Tabebuia rosea no presentaron diferencias significativas entre tratamientos (PG>90%). La respuesta a la temperatura mostró que 25/30°C es el régimen más adecuado para promover la germinación de la mayoría de las especies. Las semillas de las cuatro especies evaluadas presentaron un comportamiento ortodoxo en el almacenamiento. Se concluye que las semillas de P. dulce, J. caucana y T. rosea son indiferentes a las condiciones de luz y temperatura probadas, confiriéndoles ciertas ventajas en procesos de colonización y establecimiento frente a S. saman, cuya germinación no se ve favorecida en la oscuridad. Se sugiere el uso de semillas de P. dulce, J. caucana y T. rosea en proyectos de restauración ecológica del bosque seco Tropical, debido a su tolerancia y germinación en condiciones ambientales con intervalos amplios de temperatura y luminosidad. Mientras que, semillas de S. saman podrían ser usadas en sitios abiertos como claros de bosques.

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Este estudio tuvo por objetivo relacionar la estructura anatómica foliar con las características ecofisiológicas de Cordia thaisiana (Boraginaceae), Cedrela odorata y Swietenia macrophylla (Meliaceae) y Tabebuia rosea (Bignoniaceae) durante la fase de establecimiento (<2 años), cultivadas en una región al Sur del Lago de Maracaibo, Venezuela. Se realizaron cortes transversales de las láminas foliares, tinciones, mediciones de intercambio gaseoso (CO2 y H2O) y mediciones de crecimiento. Todas las especies presentaron hojas hipoestomáticas, con epidermis uniestratificada en ambas caras, mesófilo bifacial, parénquima esponjoso medianamente laxo y estomas anomocíticos. Se detectaron diferencias significativas para las variables número de estomas/mm², espesores de lámina foliar, parénquima en empalizada, parénquima esponjoso y epidermis. La mayor tasa de asimilación (A) de CO2 ocurrió en C. odorata y la menor en C. thaisiana. Esta última especie presentó los mejores rendimientos en crecimiento diametral y longitudinal, y, en consecuencia, es la especie más apta para integrar plantaciones agroforestales en el sitio estudiado.

The aim of the study was to compare anatomical structure of the leaves and ecophysiological traits of the species Cordia thaisiana (Boraginaceae), Cedrela odorata, Swietenia macrophylla (Meliaceae) and Tabebuia rosea (Bignoniaceae) cultivated in the South of the Maracaibo Lake, Venezuela. Transverse leaf sections were prepared and stained, and gas exchange (CO2 and H2O) and growth were measured. All the species had hypostomatics leaves with monostratified epidermis at both surfaces, bifacial mesophyll moderately lax spongy parenchyma, and anomocytic stomata. Significant differences were found for the number of stomata/mm² and leaf thickness, as well as palisade, spongy parenchyma and epidermis thicknesses. The gas exchange parameters showed that C. odorata has the highest photosynthetic rate (A) and C. thaisiana the lowest rate. The latter species presented better yields, with higher diametrical and length growth, being thus recommended for agroforestry plantations in the studied site.

Este estudo teve por objetivo relacionar a estrutura anatômica foliar com as características ecofisiológicas de Cordia thaisiana (Boraginaceae), Cedrela odorata e Swietenia macrophylla (Meliaceae) e Tabebuia rosea (Bignoniaceae) durante a fase de estabelecimento (<2 anos), cultivadas em uma região ao Sul do Lago de Maracaibo, Venezuela. Realizaram-se cortes transversais das lâminas foliares, tinção, medições de intercâmbio gasoso (CO2 e H2O) e medições de crescimento. Todas as espécies apresentaram folhas hipoestomáticas, com epiderme uniestratificada em ambas caras, mesófilo bifacial, parênquima esponjoso medianamente laxo e estomatos anomocíticos. Detectaram-se diferenças significativas para as variáveis número de estomas/mm², espessores de lâmina foliar, parênquima em empalizada, parênquima esponjoso e epiderme. A maior taxa de assimilação (A) de CO2 ocorreu em C. odorata e a menor em C. thaisiana. Esta última espécie apresentou os melhores rendimentos em crescimento diametral e longitudinal, e, em consequência, é a espécie mais apta para integrar plantações agroflorestais na área estudada.

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We evaluated the effect of soil "scarification" and vegetation clearing treatments on the natural regeneration and initial development of Tabebuia rosea (Bertold) DC. seedlings in a moderate sized semideciduous tropical forest subjected to wood harvesting on the coast of Jalisco, Mexico. The treatments were applied under "seed" trees, and the number of germinated seedlings and their development were evaluated for nine months. Soil "scarification" promoted seed germination and initial seedling development, while the control of the competing vegetation increased the seedling growth and reduced their mortality. These results should be taken into account for the natural regeneration of this species, after clearing, to improve wood production, and should be incorporated into the silvicultural techniques currently developed in the region.

Evaluamos el efecto de los tratamientos de remoción de suelo y roza de vegetación sobre el establecimiento y desarrollo inicial de la regeneración natural de Tabebuia rosea (Bertold) DC. en una selva mediana subcaducifolia sometida a aprovechamiento maderable en la costa de Jalisco, México. Los tratamientos se aplicaron bajo la copa de árboles “semilleros” y se evaluó el número de plántulas emergidas y su desarrollo durante nueve meses. El tratamiento de remoción de suelo favoreció la emergencia de plántulas y su desarrollo inicial, mientras que el control de la vegetación competidora promovió un mayor crecimiento y menores porcentajes de mortalidad. Estos aspectos deben tomarse en cuenta para la regeneración natural de la especie después de la aplicación de las cortas con fines de aprovechamiento maderable y se sugiere incorporarlos a las técnicas silvícolas que actualmente se desarrollan en la zona.

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El presente trabajo tuvo por objetivo multiplicar y mantener in vitro plantas de Tabebuia rosea y de Cordia alliodora, a partir de semillas de cinco árboles plus de la primera especie y uno de la segunda. A partir de este material se seleccionaron plantas núcleo (PN), Yemas apicales de las plantas núcleo obtenidas, fueron removidas y cultivadas bajo condiciones in vitro hasta producir 1480 plantas de las dos especies. El proceso de aclimatización del material vegetal se llevó a cabo bajo condiciones de invernadero, en cámaras húmedas ubicadas en la estación experimental "Bambusa" en Pacho, Cundinamarca. Para el manejo de la información, se diseñó una base de datos en el programa Access, Microsoft Office®, con el fin de monitorear y evaluar el comportamiento de cada uno de los individuos durante el desarrollo in vitro, por medio del cálculo de tasas de velocidad de multiplicación (TVM), tasa de pérdida (TP) y tasa de eficiencia del proceso (TE). Este material será entregado a Conif para el establecimiento de la primera plantación de origen in vitro, que será utilizada posteriormente para ensayos de propagación vegetativa, análisis de pruebas clonales y moleculares.

This work was aimed at multiplying and maintaining in vitro plants from seedlings from five Tabebuia rosea (large spreading cedar tree) from and one Cordia alliodora (walnut tree used for providing shade for coffee plantations). Apical leaf buds were excised from mother plants (MP) and cultured in vitro until 1480 plants had been produced from the two species. The hardening process was carried out in greenhouse conditions using humid flow-chambers at Geoambiente Ltda’s Bambusa experimental station in Pacho, Cundinamarca. A database was created using Microsoft Office Access software for handling information required for monitoring and evaluating each plant’s behaviour during the in vitro culture process by calculating the rates of multiplication (RM) and loss(RL). The plants so produced will be used by Conif for field trials and evaluation purposes. This material will then be multiplied by vegetative propagation and used for clone and molecular testing analysis.

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