In Vitro Anti-Toxoplasma Activity of Extracts Obtained from Tabebuia rosea and Tabebuia chrysantha: The Role of ß-Amyrin.

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.

Anti-Inflammatory Effect of Ethanolic Extract from Tabebuia rosea (Bertol.) DC., Quercetin, and Anti-Obesity Drugs in Adipose Tissue in Wistar Rats with Diet-Induced Obesity.

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.

Anticancer potential and toxicity of the genus Handroanthus Mattos (Bignoniaceae): A systematic review.

The genus Handroanthus Mattos (Bignoniaceae) is widely used for the treatment of cancer in traditional medicine in Brazil and other South American countries. The anticancer potential of species of this genus has been reported in the literature, indicating that their chemical compounds may be effective against different tumor cell lines. In this perspective, the present study aimed to conduct a systematic review of ethnobotanical, pharmacological, phytochemical and toxicological information on Handroanthus species related to cancer treatment. Searches were conducted in the Google Scholar, PubMed®, ScienceDirect® and SciELO databases. A total of 78 articles published in the last thirty-two years (1990-2022) were eligible and included in the review. According to the scientific documents analyzed, five species of Handroanthus are widely used for the treatment of cancer in the traditional medicine of Brazil and other South American countries, including Bolivia and Argentina. The bark (88%) is the main part used in traditional preparations. Extracts and fractions from Handroanthus showed cytotoxicity against the following tumor cell lines: HL-60, MDA-MB-435, MDA-MB-231, MCF-7, HT-29, HCT-8, HCT-116, HEp-2, HepG2, CACO-2, SF-295, NCI-H292, NCI-H460, HeLa, and OVCAR-8. ß-Lapachone, a naphthoquinone isolated from some species of this genus, is the most investigated compound for anticancer potential and has proved effective against some lung cancer cell lines (CL1-1, CL1-5 and A549). Results related to toxicological studies were not conclusive, considering that some extracts and compounds isolated from plants of this genus may present some degree of toxicity depending on the time of use and the concentration/dose used. Thus, despite the promising effects against various cancer cell lines, caution is needed when making use of these products.

RNA-Seq reveals different responses to drought in Neotropical trees from savannas and seasonally dry forests.

BACKGROUND: Water is one of the main limiting factors for plant growth and crop productivity. Plants constantly monitor water availability and can rapidly adjust their metabolism by altering gene expression. This leads to phenotypic plasticity, which aids rapid adaptation to climate changes. Here, we address phenotypic plasticity under drought stress by analyzing differentially expressed genes (DEG) in four phylogenetically related neotropical Bignoniaceae tree species: two from savanna, Handroanthus ochraceus and Tabebuia aurea, and two from seasonally dry tropical forests (SDTF), Handroanthus impetiginosus and Handroanthus serratifolius. To the best of our knowledge, this is the first report of an RNA-Seq study comparing tree species from seasonally dry tropical forest and savanna ecosystems. RESULTS: Using a completely randomized block design with 4 species × 2 treatments (drought and wet) × 3 blocks (24 plants) and an RNA-seq approach, we detected a higher number of DEGs between treatments for the SDTF species H. serratifolius (3153 up-regulated and 2821 down-regulated under drought) and H. impetiginosus (332 and 207), than for the savanna species. H. ochraceus showed the lowest number of DEGs, with only five up and nine down-regulated genes, while T. aurea exhibited 242 up- and 96 down-regulated genes. The number of shared DEGs among species was not related to habitat of origin or phylogenetic relationship, since both T. aurea and H impetiginosus shared a similar number of DEGs with H. serratifolius. All four species shared a low number of enriched gene ontology (GO) terms and, in general, exhibited different mechanisms of response to water deficit. We also found 175 down-regulated and 255 up-regulated transcription factors from several families, indicating the importance of these master regulators in drought response. CONCLUSION: Our findings show that phylogenetically related species may respond differently at gene expression level to drought stress. Savanna species seem to be less responsive to drought at the transcriptional level, likely due to morphological and anatomical adaptations to seasonal drought. The species with the largest geographic range and widest edaphic-climatic niche, H. serratifolius, was the most responsive, exhibiting the highest number of DEG and up- and down-regulated transcription factors (TF).

In vivo effects of exposure to Golden trumpet Handroanthus chrysotrichus in mice.

The Golden trumpet Handroanthus chrysotrichus is a tree that presents beneficial health properties against various diseases. Thus, this study aims to verify the toxicity of H. chrysotrichus bark extract, observing the effects of exposure to this extract in mice. For this, mice were separated in groups: saline (sterile solution .9%); H. chrysotrichus crude extract (HCCE) 10; HCCE 50, and HCCE 100 mg. kg-1 (p.o.). We analyzed HCCE effects on acute (single exposure) and subchronic protocol (14 days exposure). After both exposures, acute, and subchronic, we collected samples from blood, brain, liver, and kidney tissues for biochemical evaluation. In addition, after subchronic exposure, we performed behavioral tests. Acute exposure caused an increase of lipid peroxidation in liver tissue. Moreover, we observed a significant carbonyl increase in liver and brain tissues from HCCE 50 mg. kg-1. Kidneys presented carbonyl increase in mice treated with the highest concentration. Besides, creatinine increased in the group of the acute exposure at HCCE 100 mg. kg-1. Total leukocyte count decreased in all concentrations tested. Sub-chronic exposure at HCCE 100 mg. kg-1 caused a decrease in the number of crossing and an increase in its self-grooming frequency in the open field test. In this exposure, the brain and liver had a significant increase in carbonyl levels in all concentrations. We concluded that H. chrysotrichus cause behavioral and biochemical alterations in mice. HCCE primary targets seem to be the liver, kidneys, and white cells.

Cytotoxicity assessment of beta-lapachone in endothelial cells

The selective activity of an antineoplastic drug is related to its ability to promote cytotoxic action on tumor cells and preserve the integrity of non-neoplastic cells. Beta-lapachone is extracted from the sawdust of Ipe wood, a thick bark tree from the Ipe wood found in the Brazilian Cerrado biome. This study aimed to evaluate the cytotoxic action of beta-lapachone in an endothelial cell line. The EA.hy926 cells were seeded in two groups, G1 and G2, cultured and exposed to beta-lapachone at concentrations of 0.0, 0.01, 0.03, 0.1, 0.3, 1 and 3 & 956;M for 24 hours. G1 remained under normal cultivation conditions and G2 was subjected to oxidative stress through an ischemia and reperfusion assay, in a deoxygenated sealed chamber. The cytotoxicity assay was performed using the tetrazolium reduction method. In G1, the cytotoxicity ranged from 0.0 to 10.0%; and in G2 between 0.0 and 6.3%. No statistically significant difference was observed between the obtained values. Moreover, we found no cytotoxic action of beta-lapachone on endothelial cells, and the results point out that the drug might have preserved the cells integrity against oxidative stress under the conditions of this experiment. This promising result suggests the possibility of beta-lapachone as a chemotherapy drug with selective activity.(AU)

Cytotoxicity assessment of beta-lapachone in endothelial cells

The selective activity of an antineoplastic drug is related to its ability to promote cytotoxic action on tumor cells and preserve the integrity of non-neoplastic cells. Beta-lapachone is extracted from the sawdust of Ipe wood, a thick bark tree from the Ipe wood found in the Brazilian Cerrado biome. This study aimed to evaluate the cytotoxic action of beta-lapachone in an endothelial cell line. The EA.hy926 cells were seeded in two groups, G1 and G2, cultured and exposed to beta-lapachone at concentrations of 0.0, 0.01, 0.03, 0.1, 0.3, 1 and 3 & 956;M for 24 hours. G1 remained under normal cultivation conditions and G2 was subjected to oxidative stress through an ischemia and reperfusion assay, in a deoxygenated sealed chamber. The cytotoxicity assay was performed using the tetrazolium reduction method. In G1, the cytotoxicity ranged from 0.0 to 10.0%; and in G2 between 0.0 and 6.3%. No statistically significant difference was observed between the obtained values. Moreover, we found no cytotoxic action of beta-lapachone on endothelial cells, and the results point out that the drug might have preserved the cell’s integrity against oxidative stress under the conditions of this experiment. This promising result suggests the possibility of beta-lapachone as a chemotherapy drug with selective activity.

Activation of the Keap1-Nrf2 pathway by specioside and the n-butanol extract from the inner bark of Tabebuia rosea (Bertol) DC.

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.

Multi-Scale Landscape Influences on Genetic Diversity and Adaptive Traits in a Neotropical Savanna Tree.

Changes in landscape structure can affect essential population ecological features, such as dispersal and recruitment, and thus genetic processes. Here, we analyze the effects of landscape metrics on adaptive quantitative traits variation, evolutionary potential, and on neutral genetic diversity in populations of the Neotropical savanna tree Tabebuia aurea. Using a multi-scale approach, we sampled five landscapes with two sites of savanna in each. To obtain neutral genetic variation, we genotyped 60 adult individuals from each site using 10 microsatellite loci. We measured seed size and mass. Seeds were grown in nursery in completely randomized experimental design and 17 traits were measured in seedlings to obtain the average, additive genetic variance (V a ) and coefficient of variation (CV a %), which measures evolvability, for each trait. We found that habitat loss increased genetic diversity (He) and allelic richness (AR), and decreased genetic differentiation among populations (F ST ), most likely due to longer dispersal distance of pollen in landscapes with lower density of flowering individuals. Habitat amount positively influenced seed size. Seeds of T. aurea are wind-dispersed and larger seeds may be dispersed to short distance, increasing genetic differentiation and decreasing genetic diversity and allelic richness. Evolvability (CV a %) in root length decreased with habitat amount. Savanna trees have higher root than shoot growth rate in the initial stages, allowing seedlings to obtain water from water tables. Landscapes with lower habitat amount may be more stressful for plant species, due to the lower plant density, edge effects and the negative impacts of agroecosystems. In these landscapes, larger roots may provide higher ability to obtain water, increasing survival and avoiding dying back because of fire. Despite the very recent agriculture expansion in Central Brazil, landscape changes are affecting neutral and adaptive variation in T. aurea. Several populations have low additive genetic variation for some traits and thus, may have limited evolvability, which may jeopardize species long-term persistence. The effect of habitat loss on highly variable neutral loci may only be detected after a certain threshold of population size is attained, that could become dangerously small masking important losses of heterozygosity endangering species conservation.

Identificación morfológica y comprobación de patogenicidad de agentes biológicos asociados Tabebuia rosea (Bertol) en etapa de vivero en Morelia (Risaralda) / Morphological identification of pathogenic agents associated with Tabebuia rosea (Bignoniaceae) in nursery stage in morelia (Risaralda)

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

Beta Lapachone blocks the cell cycle and induces apoptosis in canine osteosarcoma cells / Beta Lapachona bloqueia o ciclo celular e induz apoptose em células de osteossarcoma canino

Osteosarcoma is a malignant tumor of primitive bone cells with a high incidence in dogs and humans. The need for more effective drugs with less adverse consequences has pushed the development of chemotherapeutic agents from plants and other natural sources. The aim of this study was to verify the cytotoxic effects of beta-lapachone, a compound present in the sawdust of Tabebuia sp. (popularly known as ipê) wood, on canine osteosarcoma cells subcultured and treated in different concentrations (0.1µm, 0.3µm e 1.0µm) and exposure times (24h, 48h e 72h). Results were obtained through Trypan blue dye exclusion, tetrazolium reducing method, cell survival assay, Annexin V-FITC and Propidium Iodine labeling, JC-1 dye labeling and cell cycle kinetics e analysis. The group treated with 0.3µm beta-lapachone presented higher decrease in cell viability (80.27%, 24h, 47.41%, 48h and 35.19%, 72h) and greater progression of cytotoxicity (19.73%, 24h, 52.59%, 48h and 64.81%, 72h). The lower IC50 (0.180µm) was verified in the group treated for 72 hours. Cell growth after treatment decreased as concentration and time of exposure increased, with 0.50% survival fraction at the concentration of 1.0µm. Initial apoptosis was the most frequent type of cell death in all groups, reaching bottom in the 24-hour group treated with 0.1µm (4.26%) and peaking in the 72-hour group treated with 1.0µm (85.89%). Mitochondrial depolarization demonstrated a dose-dependent phenomenon, indicating the intrinsic apoptosis. Cell growth inhibition by blocking cell cycle in the G0/G1 phase related to the exposure the time. β-lapachone is cytotoxic for canine osteosarcoma cells, induces apoptosis and promotes cell cycle arrest in G0/G1 phase.(AU)

O osteossarcoma é o tumor maligno das células ósseas primitivas, com alta incidência em cães e humanos. A necessidade de medicamentos mais efetivos, com menor consequência adversa, tem gerado esforços para o desenvolvimento de agentes quimioterápicos compostos por plantas e outras fontes naturais. O objetivo deste estudo foi verificar os efeitos citotóxicos da beta lapachona, um composto presente na serragem da madeira do ipê, sobre células de osteossarcoma canino subcultivadas e submetidas ao tratamento, de acordo com as diferentes concentrações (0.1µm, 0.3µm e 1.0µm) e tempo de exposição (24h, 48h e 72h). Os resultados foram obtidos por meio dos métodos de exclusão do corante azul de Tripan e de redução do tetrazólio, além dos ensaios de sobrevivência celular, de dupla marcação com Anexina V-FITC e Iodeto de Propídio, de marcação com o corante JC-1 e pela análise da cinética do ciclo celular. O grupo tratado com 0.3µm de beta lapachona apresentou melhor regressão da viabilidade celular (80,27%, 24h; 47,41%, 48h e 35,19%, 72h) e maior progressão da citotoxicidade (19,73%, 24h; 52,59%, 48h e 64,81%, 72h). O menor IC50 (0.180µm) ocorreu no grupo tratado por 72 horas. O crescimento celular após o tratamento foi menor, de acordo com o aumento da concentração e tempo de exposição, apresentando 0,50% de fração de sobrevivência na concentração de 1.0µm. A apoptose inicial foi o tipo de morte celular mais frequente em todos os grupos, menor no grupo de 24 horas tratado com 0.1µm (4,26%) e maior no grupo de 72 horas tratado com 1.0µm (85,89%). A despolarização mitocondrial ocorreu de maneira dose dependente, indicando a ocorrência de apoptose intrínseca. A β lapachona possui efeitos citotóxicos em células de osteossarcoma canino, induz apoptose e promove o bloqueio do ciclo celular na fase G0/G1.(AU)

Beta Lapachone blocks the cell cycle and induces apoptosis in canine osteosarcoma cells / Beta Lapachona bloqueia o ciclo celular e induz apoptose em células de osteossarcoma canino

Osteosarcoma is a malignant tumor of primitive bone cells with a high incidence in dogs and humans. The need for more effective drugs with less adverse consequences has pushed the development of chemotherapeutic agents from plants and other natural sources. The aim of this study was to verify the cytotoxic effects of beta-lapachone, a compound present in the sawdust of Tabebuia sp. (popularly known as ipê) wood, on canine osteosarcoma cells subcultured and treated in different concentrations (0.1µm, 0.3µm e 1.0µm) and exposure times (24h, 48h e 72h). Results were obtained through Trypan blue dye exclusion, tetrazolium reducing method, cell survival assay, Annexin V-FITC and Propidium Iodine labeling, JC-1 dye labeling and cell cycle kinetics e analysis. The group treated with 0.3µm beta-lapachone presented higher decrease in cell viability (80.27%, 24h, 47.41%, 48h and 35.19%, 72h) and greater progression of cytotoxicity (19.73%, 24h, 52.59%, 48h and 64.81%, 72h). The lower IC50 (0.180µm) was verified in the group treated for 72 hours. Cell growth after treatment decreased as concentration and time of exposure increased, with 0.50% survival fraction at the concentration of 1.0µm. Initial apoptosis was the most frequent type of cell death in all groups, reaching bottom in the 24-hour group treated with 0.1µm (4.26%) and peaking in the 72-hour group treated with 1.0µm (85.89%). Mitochondrial depolarization demonstrated a dose-dependent phenomenon, indicating the intrinsic apoptosis. Cell growth inhibition by blocking cell cycle in the G0/G1 phase related to the exposure the time. β-lapachone is cytotoxic for canine osteosarcoma cells, induces apoptosis and promotes cell cycle arrest in G0/G1 phase.(AU)

O osteossarcoma é o tumor maligno das células ósseas primitivas, com alta incidência em cães e humanos. A necessidade de medicamentos mais efetivos, com menor consequência adversa, tem gerado esforços para o desenvolvimento de agentes quimioterápicos compostos por plantas e outras fontes naturais. O objetivo deste estudo foi verificar os efeitos citotóxicos da beta lapachona, um composto presente na serragem da madeira do ipê, sobre células de osteossarcoma canino subcultivadas e submetidas ao tratamento, de acordo com as diferentes concentrações (0.1µm, 0.3µm e 1.0µm) e tempo de exposição (24h, 48h e 72h). Os resultados foram obtidos por meio dos métodos de exclusão do corante azul de Tripan e de redução do tetrazólio, além dos ensaios de sobrevivência celular, de dupla marcação com Anexina V-FITC e Iodeto de Propídio, de marcação com o corante JC-1 e pela análise da cinética do ciclo celular. O grupo tratado com 0.3µm de beta lapachona apresentou melhor regressão da viabilidade celular (80,27%, 24h; 47,41%, 48h e 35,19%, 72h) e maior progressão da citotoxicidade (19,73%, 24h; 52,59%, 48h e 64,81%, 72h). O menor IC50 (0.180µm) ocorreu no grupo tratado por 72 horas. O crescimento celular após o tratamento foi menor, de acordo com o aumento da concentração e tempo de exposição, apresentando 0,50% de fração de sobrevivência na concentração de 1.0µm. A apoptose inicial foi o tipo de morte celular mais frequente em todos os grupos, menor no grupo de 24 horas tratado com 0.1µm (4,26%) e maior no grupo de 72 horas tratado com 1.0µm (85,89%). A despolarização mitocondrial ocorreu de maneira dose dependente, indicando a ocorrência de apoptose intrínseca. A β lapachona possui efeitos citotóxicos em células de osteossarcoma canino, induz apoptose e promove o bloqueio do ciclo celular na fase G0/G1.(AU)

Endophytic fungi isolated from medicinal plants: future prospects of bioactive natural products from Tabebuia/Handroanthus endophytes.

Medicinal plants are a rich source of natural products used to treat many diseases; therefore, they are the basis for a new drug discovery. Plants are capable of generating different bioactive secondary metabolites, but a large amount of botanical material is often necessary to obtain small amounts of the target substance. Nowadays, many medicinal plants are becoming rather scarce. For this reason, it is important to point out the interactions between endophytic microorganisms and the host plant, because endophytes are able to produce highly diverse compounds, including those from host plants that have important biological activities. Thence, this review aims at presenting the richness in bioactive compounds of the medicinal plants from Tabebuia and Handroanthus genera, as well as important aspects about endophyte-plant interactions, with emphasis on the production of bioactive compounds by endophytic fungi, which has been isolated from various medicinal plants for such a purpose. Furthermore, bio-prospection of natural products synthesized by endophytes isolated from the aforementioned genera used in traditional medicine could be used to treat illnesses.

Nrf2-Mediated Antioxidant Activity of the inner bark extracts obtained from Tabebuia rosea (Bertol) DC and Tabebuia chrysantha (JACQ) G. Nicholson.

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.

The Antinociceptive Effect of the Leaves and Flowers Ethanolic Extracts of Tabebuia aurea (Silva Manso) Benth & Hook. F. ex S. Moore

ABSTRACT In view of the traditional use of Tabebuia aurea for treating pain and inflammation, the antinociceptive pharmacological potential of T. aurea ethanolic extracts (TAEE) was investigated through in vivo experimental models. First, the MTT assay was conducted to determine the potential cytotoxicity of the TAEEs. Afterwards, the acetic acid-induced writhing test and the formalin-, and glutamate-induced nociception tests were performed on Swiss adult mice treated with TAEEs (100 and 200 mg/kg doses, p.o.), or saline solution (control groups, 10mL/kg, p.o.), or standard drugs: dipyrone 40 mg/kg (p.o.), and morphine 5,7 mg/kg (i.p). In the MTT assay, none of the tested concentrations demonstrated signals of cytotoxicity. In the in vivo experimental models of acetic acid-induced writhing and glutamate-induced nociception, all TAEEs doses were able to statistically reduce the nociceptive response. However, the TAEEs did not show significant decrease in the amount of time that the animals spent licking the stimulated paw in the neurogenic phase of formalin-induced nociception test, differently of what was observed in the inflammatory phase. The results showed that T. aurea species induce an antinociceptive effect in rodents, which encourages the study of new drugs and contributes to the research on natural products.

Evaluation of antipyretic, sedative and hypnotic activities of methanol extract of Tabebuia hypoleuca (C. Wright ex Sauvalle) Urb. stems / [Evaluación de la actividad antipirética, sedante e hipnótica del extracto metanólico de los tallos de Tabebuia hypoleuca (C. Wright ex Sauvalle) Urb

Species of the genus Tabebuia are used in traditional medicine and are reported in the literature for their properties against various diseases. The objective of this study was to evaluate the antipyretic, sedative and hypnotic activities of methanol extract of Tabebuia hypoleuca stems (THME) using the Brewer's yeast induced pyrexia, Open field and Sodium thiopental-induced sleeping time tests, respectively. In the Brewer's yeast induced pyrexia test, THME at 500 mg/kg produced a significant (p<0.001) decrease of the fever as from the first hour after administration and was sustained for 4 h. In the Open-field test, THME did not cause any significant change in the number of crossings, rearing, preening and defecation, and either in the time of immobility. Moreover, THME did not produce changes in neither the sleeping latency nor the sleeping time induced by sodium thiopental. These results showed that THME administered orally at 500 mg/kg exerts antipyretic activity, probably mediated by the inhibition of the enzyme cyclooxygenase-2. This study also showed that THME does not exert sedative and hypnotic effects at the doses tested.

Especies del género Tabebuia se utilizan en la medicina tradicional y se reportan en la literatura por sus propiedades contra diversas enfermedades. El objetivo de este estudio fue evaluar la actividad antipirética, sedante e hipnótica del extracto metanólico de los tallos de Tabebuia hypoleuca (THME) utilizando las pruebas de pirexia inducida por levadura de cerveza, campo abierto y tiempo de sueño inducido por tiopental sódico respectivamente. En el ensayo de pirexia inducida por levadura de cerveza, THME a 500 mg/kg produjo una reducción significativa (p<0.001) de la fiebre a partir de la primera hora después de la administración y se mantuvo durante cuatro horas. En el ensayo de campo abierto, THME no causó ningún cambio significativo en el número de cruces, levantamientos, acicalamientos y defecación, ni en el tiempo de inmovilidad. Además, THME no produjo cambios ni en la latencia de sueño, ni en el tiempo de sueño inducido por tiopental sódico. Estos resultados mostraron que THME administrado oralmente en dosis de 500 mg/kg posee actividad antipirética, mediado probablemente a la inhibición de la enzima ciclooxigenasa-2. Este estudio también demostró que THME no posee actividad sedante e hipnótica en las dosis ensayadas.

Effects of changes in micro-weather conditions on structural features, total protein and carbohydrate content in leaves of the Atlantic rain forest tree golden trumpet (Tabebuia chrysotricha) / Efeito de alterações nas condições micro-climáticas sobre características estruturais, e proteína e carboidratos histoquimicamente marcados, de folhas da árvore da floresta Atlântica ipê amarelo

Abstract Golden trumpet, Tabebuia chrysotricha, is a native tree from the Brazilian Atlantic rain forest, with a broad latitudinal distribution. In this study, we investigated the potential effects of short-term changes in micro-weather conditions on structural features, and total protein and carbohydrate content of golden trumpet leaves, using structural and histochemical approaches. Leaves were harvested in four different micro-weather conditions: 1. Afternoon, after a hot, sunny day; 2. at dawn, after a previously hot, sunny day; 3. at noon, of a hot, sunny day; and 4. at noon, of a cold, cloudy day. Leaflets exposed to low light irradiance showed flattened chloroplasts, uniformly distributed within the cells, throughout the palisade parenchyma. Conversely, leaflets exposed to high light irradiance presented flattened and rounded chloroplasts, in the upper and lower palisade parenchyma cells, respectively. The strongest protein staining was found for leaves harvested at the coldest period, whereas the weakest protein staining was found for leaves harvested after a hot, sunny day. The largest and most numerous starch grains were found for leaves harvested in the afternoon, after a hot, sunny day. Conversely, the smallest and less numerous starch grains were found for leaves harvested at dawn. Analysis of the data reported herein suggests that the leaflet responses to transient changes in micro-weather conditions are likely to contribute to the golden trumpet successful establishment in the broad latitudinal distribution in which the species is found.

Resumo Ipê amarelo é uma árvore nativa da floresta Atlântica brasileira, encontrada em uma ampla distribuição latitudinal. Neste estudo, nós investigamos os efeitos potenciais de alterações de curto prazo nas condições micro-climáticas sobre características estruturais, proteína e carboidratos histoquimicamente marcados, de folhas de ipê amarelo, usando estratégias de análise estrutural e histoquímicas. As folhas foram marcadas em quatro condições microclimáticas distintas: 1. Tarde, após um dia quente e ensolarado; 2. Amanhecer, após um dia quente e ensolarado; 3. Ao meio-dia, de um dia quente e ensolarado; e 4. Ao meio-dia, de um dia frio e nublado. Folíolos expostos à baixa irradiância luminosa apresentaram cloroplastos achatados, uniformemente distribuídos no interior das células, por todo o parênquima paliçádico, enquanto que folíolos expostos à alta irradiância apresentaram cloroplastos achatados e arredondados, nas células superiores e inferiores do parênquima paliçádico, respectivamente. A marcação mais intensa para proteína foi observada para folhas coletadas no momento mais frio de coleta, enquanto que a marcação mais fraca foi observada para folhas coletadas após um dia quente e ensolarado. Os grãos de amido maiores e mais numerosos foram observados em folhas coletadas durante a tarde de dia quente e ensolarado, enquanto que os menores e menos numerosos grãos de amido foram observados em folhas coletadas ao amanhecer.

Antinociceptive Activity of Methanol Extract of Tabebuia hypoleuca (C. Wright ex Sauvalle) Urb. Stems.

OBJECTIVE: The aim of this study was to evaluate the antinociceptive activity of the methanol extract of Tabebuia hypoleuca stems (THME). MATERIALS AND METHODS: The animals were divided into 5 groups of 8 mice for each test (negative controls, positive controls, and 3 groups treated with THME at doses of 150, 300, and 500 mg/kg, p.o.). The antinociceptive effect of THME was evaluated using the writhing, formalin, tail flick, and hot plate models in mice. RESULTS: In the writhing test, THME (150, 300, and 500 mg/kg) produced significantly (p < 0.001) fewer writhes induced by acetic acid than in the control group. In the formalin test, the licking time for THME at doses of 300 and 500 mg/kg was significantly shorter (p < 0.001) compared to the control group in the first phase of the formalin test, whereas in the second phase only the dose of 500 mg/kg showed an antinociceptive effect. In addition, THME at doses of 300 and 500 mg/kg significantly increased the latency time in the tail flick test (p < 0.05 and p < 0.001, respectively) and in the hot plate test (p < 0.01 and p < 0.001, respectively) compared to the control group. CONCLUSIONS: These results show that THME had antinociceptive activity using several models of nociception, and they suggest that the effect is mediated by the participation of both peripheral and central antinociceptive mechanisms.

Effects of changes in micro-weather conditions on structural features, total protein and carbohydrate content in leaves of the Atlantic rain forest tree golden trumpet (Tabebuia chrysotricha)

Abstract Golden trumpet, Tabebuia chrysotricha, is a native tree from the Brazilian Atlantic rain forest, with a broad latitudinal distribution. In this study, we investigated the potential effects of short-term changes in micro-weather conditions on structural features, and total protein and carbohydrate content of golden trumpet leaves, using structural and histochemical approaches. Leaves were harvested in four different micro-weather conditions: 1. Afternoon, after a hot, sunny day; 2. at dawn, after a previously hot, sunny day; 3. at noon, of a hot, sunny day; and 4. at noon, of a cold, cloudy day. Leaflets exposed to low light irradiance showed flattened chloroplasts, uniformly distributed within the cells, throughout the palisade parenchyma. Conversely, leaflets exposed to high light irradiance presented flattened and rounded chloroplasts, in the upper and lower palisade parenchyma cells, respectively. The strongest protein staining was found for leaves harvested at the coldest period, whereas the weakest protein staining was found for leaves harvested after a hot, sunny day. The largest and most numerous starch grains were found for leaves harvested in the afternoon, after a hot, sunny day. Conversely, the smallest and less numerous starch grains were found for leaves harvested at dawn. Analysis of the data reported herein suggests that the leaflet responses to transient changes in micro-weather conditions are likely to contribute to the golden trumpet successful establishment in the broad latitudinal distribution in which the species is found.

Resumo Ipê amarelo é uma árvore nativa da floresta Atlântica brasileira, encontrada em uma ampla distribuição latitudinal. Neste estudo, nós investigamos os efeitos potenciais de alterações de curto prazo nas condições micro-climáticas sobre características estruturais, proteína e carboidratos histoquimicamente marcados, de folhas de ipê amarelo, usando estratégias de análise estrutural e histoquímicas. As folhas foram marcadas em quatro condições microclimáticas distintas: 1. Tarde, após um dia quente e ensolarado; 2. Amanhecer, após um dia quente e ensolarado; 3. Ao meio-dia, de um dia quente e ensolarado; e 4. Ao meio-dia, de um dia frio e nublado. Folíolos expostos à baixa irradiância luminosa apresentaram cloroplastos achatados, uniformemente distribuídos no interior das células, por todo o parênquima paliçádico, enquanto que folíolos expostos à alta irradiância apresentaram cloroplastos achatados e arredondados, nas células superiores e inferiores do parênquima paliçádico, respectivamente. A marcação mais intensa para proteína foi observada para folhas coletadas no momento mais frio de coleta, enquanto que a marcação mais fraca foi observada para folhas coletadas após um dia quente e ensolarado. Os grãos de amido maiores e mais numerosos foram observados em folhas coletadas durante a tarde de dia quente e ensolarado, enquanto que os menores e menos numerosos grãos de amido foram observados em folhas coletadas ao amanhecer.

Two tropical conifers show strong growth and water-use efficiency responses to altered CO2 concentration.

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.