919 resultados para ethyl carbamate
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Mestrado em Engenharia Química
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The fungicidal action of sodium hypochlorite (0.3, 1, 2.5, 5 and 10%); formaldehyde (2, 5, and 10%); and ethyl alcohol (70%) on yeast forms of Paracoccidioides brasiliensis Pb 18 and a newly-isolated Goiana strain was described. Contact between the fungus and the disinfectants was maintained for 1, 2, 24, 48 and 72 hours at room temperature. Viability was evaluated by the fluorescein diacetate-ethidium bromide treatment, culture in solid and liquid media (36ºC and 26ºC); yeast to mycelial germination at room temperature; and radiometric study of metabolic activity. All concentrations of disinfectants were found to be effective in inactivating Pb 18 and Goiana strains, except for the 1-hour contact with 2% formaldehyde, in which fluorescein diacetate-ethidium bromide treatment was found to reveal 40 and 27% of viable cells, respectively. The yeast to mycelial germination method was considered to reveal faster and similar results as compared to culture in solid and liquid media.
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Aminocarb is a widely applied carbamate insecticide with action of controlling pests such as Lepidoptera and Coleoptera. In this study, subchronic effects on Wistar rats were investigated using hematological, biochemical, and histological techniques. Rats were exposed orally at sublethal levels of 10, 20, or 40 mg/kg body weight (groups A, B, and C, respectively) for 14 d. Hematological results revealed no statistical differences after 1 d of exposure but significant reduction in white blood cells detected after 7 d of exposure in group C, as well as, in all treated groups after 14 d of exposure. Biochemical data showed a decrease of acetylcholinesterase activity in all groups after 1 d of exposure with a return to normal after 7 and 14 d. Significant increase in alkaline phosphatase activity of rats exposed to aminocarb was noted after 7 d of treatment. The levels of triglycerides were also significantly decreased. The present investigation also showed a significant increase in content of serum urea and creatinine in animals from group A (14 d), and from groups B and C (7 and 14 d). Histological results demonstrated hemorrhagic focus on hepatic and renal parenchyma in all exposed groups. Taken together, the attained results were dose dependent and indicated adverse effects of aminocarb on hepatic and renal functions, as well as on immune responsiveness at sublethal tested doses.
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The ready biodegradability of four chelating agents, N,N -(S,S)-bis[1-carboxy-2-(imidazol-4-yl)ethyl]ethylenediamine (BCIEE), N - ethylenedi-L-cysteine (EC), N,N -bis (4-imidazolymethyl)ethylenediamine (EMI) and 2,6-pyridine dicarboxylic acid (PDA), was tested according to the OECD guideline for testing of chemicals. PDA proved to be a readily biodegradable substance. However, none of the other three compounds were degraded during the 28 days of the test. Chemical simulations were performed for the four compounds in order to understand their ability to complex with some metal ions (Ca, Cd, Co, Cu, Fe, Mg, Mn, Ni, Pb, Zn) and discuss possible applications of these chelating agents. Two different conditions were simulated: (i) in the presence of the chelating agent and one metal ion, and (ii) in the simultaneous presence of the chelating agent and all metal ions with an excess of Ca. For those compounds that were revealed not to be readily biodegradable (BCIEE, EC and EMI), applications were evaluated where this property was not fundamental or even not required. Chemical simulations pointed out that possible applications for these chelating agents are: food fortification, food process, fertilizers, biocides, soil remediation and treatment of metal poisoning. Additionally, chemical simulations also predicted that PDA is an efficient chelating agent for Ca incrustations removal, detergents and for pulp metal ions removal process.
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As ligações adesivas têm sido cada vez mais utilizadas nos últimos anos em detrimento de outros métodos tais como a soldadura, ligações aparafusadas e ligações rebitadas. Os plásticos de Engenharia têm um papel cada vez mais preponderante na indústria, devido às suas excelentes propriedades. Neste trabalho foram considerados três polímeros diferentes, o Policloreto de Vinilo (PVC) e o Polipropileno (PP) dado o seu baixo custo e peso e a superfície quimicamente inerte e o Politetrafluoretileno (PTFE) devido às suas boas propriedades químicas e excelentes propriedades de deslizamento. No entanto, estes materiais possuem uma baixa energia de superfície e, por isso, são muito difíceis de colar com mais relevância para o PTFE. Assim, após um estudo preliminar foi escolhido, para realizar as colagens necessárias, um adesivo da Tamarron Technology “Tam Tech Adhesive”, próprio para este tipo de substratos difíceis de colar. Posteriormente foi efetuada a sua caraterização através de ensaios de provetes maciços à tração. O principal objetivo deste trabalho foi estudar juntas de sobreposição simples de materiais poliméricos difíceis de colar tais como o PTFE, PP e PVC com recurso a um adesivo que não necessitasse de preparação de superfície. Foram fabricadas juntas de sobreposição simples (JSS) segundo os métodos Lap Shear (LS) e Block Shear (BS) dos três materiais referidos anteriormente e realizados os respetivos ensaios para avaliar o comportamento mecânico das ligações adesivas. Os materiais utilizados como substratos foram também submetidos a ensaios de tração com a finalidade de obter o módulo de elasticidade e as suas propriedades de resistência. Os substratos envolvidos nas juntas adesivas não sofreram qualquer preparação especial das superfícies. Na maioria dos casos consistiu apenas numa limpeza das superfícies com álcool etílico. Contudo, para o PTFE também se experimentou a preparação por abrasão com lixa e por chama. Foi também efetuado um trabalho de simulação numérica por elementos finitos utilizando um modelo de dano coesivo triangular. As resistências ao corte obtidas são superiores em BS comparativamente a LS, exceção feita aos substratos de PTFE aonde os resultados são similares. O tratamento por chama melhorou a resistência mecânica das juntas. Verificou-se também que o modelo numérico simulou adequadamente o comportamento das juntas principalmente das LS.
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Thesis submitted to Faculdade de Ciências e Tecnologia from Universidade Nova de Lisboa in partial fulfillment of the requirements for the obtention of the degree of Master of Science in Biotechnology
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Human cryptosporidiosis is an infection caused by Cryptosporidium spp, a coccidial protozoan of emergencial pathogenicity and responsible for severe and prostrating watery diarrhea, mainly in immunocompromised patients. Smears of stools submitted to concentration and staining by carbol fuchsin technique has been used in our laboratory as a diagnostic procedure for cryptosporidiosis. The long time observing the smears in the microscope due to the small size of the forms and the low contrast of the staining led us to introduce some modifications in the original protocol for the acid-fast staining. The smears were treated with the carbol fuchsin solution for 3 minutes as recommended by LENNETTE et al., 1985 and the solution of the ethyl alcohol 70%-chloride acid 0.5% was used instead of the ethyl alcohol-sulfuric acid 5% recommended by HENRIKSEN & POHLENZ, 1981. Smears were treated with the discoloration solution for 2 minutes. These modifications promoted a better washing out of the excess of carbol fuchsin therefore increasing the dye efficiency. In such conditions, the visualization of protozoan oocysts on the slides examined became easier. They were observed by the contrast of their intense pink-reddish pigmentation against the blue background. It's worthwhile to emphasize that these modifications offer advantages when time and accuracy are concerned.
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Increased levels of plasma oxLDL, which is the oxidized fraction of Low Density Lipoprotein (LDL), are associated with atherosclerosis, an inflammatory disease, and the subsequent development of severe cardiovascular diseases that are today a major cause of death in modern countries. It is therefore important to find a reliable and fast assay to determine oxLDL in serum. A new immunosensor employing three monoclonal antibodies (mAbs) against oxLDL is proposed in this work as a quick and effective way to monitor oxLDL. The oxLDL was first employed to produce anti-oxLDL monoclonal antibodies by hybridoma cells that were previously obtained. The immunosensor was set-up by selfassembling cysteamine (Cyst) on a gold (Au) layer (4 mm diameter) of a disposable screen-printed electrode. Three mAbs were allowed to react with N-hydroxysuccinimide (NHS) and ethyl(dimethylaminopropyl)carbodiimide (EDAC), and subsequently incubated in the Au/Cys. Albumin from bovine serum (BSA) was immobilized further to ensure that other molecules apart from oxLDL could not bind to the electrode surface. All steps were followed by various characterization techniques such as electrochemical impedance spectroscopy (EIS) and square wave voltammetry (SWV). The analytical operation of the immunosensor was obtained by incubating the sensing layer of the device in oxLDL for 15 minutes, prior to EIS and SWV. This was done by using standard oxLDL solutions prepared in foetal calf serum, in order to simulate patient's plasma with circulating oxLDL. A sensitive response was observed from 0.5 to 18.0 mg mL 1 . The device was successfully applied to determine the oxLDL fraction in real serum, without prior dilution or necessary chemical treatment. The use of multiple monoclonal antibodies on a biosensing platform seemed to be a successful approach to produce a specific response towards a complex multi-analyte target, correlating well with the level of oxLDL within atherosclerosis disease, in a simple, fast and cheap way.
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Carbamate compounds are an important group of cholinesterase inhibitors. There is a need for creating awareness regarding the risks of the inadequate carbamate use in the residential areas due to potential adverse human effects. Carbaryl is a commonly used pesticide worldwide. A simple, fast, and high throughput method was developed employing liquid chromatography with fluorescence detector to determine carbaryl residues in rat feces. The extraction was performed by using a rapid, easy, cheap, effective, reliable, and safe (QuEChERS) method, using acetonitrile as the extracting solvent. The parameters for the performance of the extraction method were optimized, such as ratio of mass of sample per volume of extraction solvent, QuEChERS content, and cleanup columns. Linear response was obtained for all calibration curves (solven and matrix-matched) over the established concentration range (5 500 mg/L) with a correlation coefficients higher than 0.999. The achieved recovery was 97.9% with relative standard deviation values of 1.1% (n D 4) at 167 mg/kg fortified concentration level and the limits of detection and quantification were 27.7 and 92.3 mg/kg respectively.
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Guava leaf tea of Psidium guajava Linnaeus is commonly used as a medicine against gastroenteritis and child diarrhea by those who cannot afford or do not have access to antibiotics. This study screened the antimicrobial effect of essential oils and methanol, hexane, ethyl acetate extracts from guava leaves. The extracts were tested against diarrhea-causing bacteria: Staphylococcus aureus, Salmonella spp. and Escherichia coli. Strains that were screened included isolates from seabob shrimp, Xiphopenaeus kroyeri (Heller) and laboratory-type strains. Of the bacteria tested, Staphylococcus aureus strains were most inhibited by the extracts. The methanol extract showed greatest bacterial inhibition. No statistically significant differences were observed between the tested extract concentrations and their effect. The essential oil extract showed inhibitory activity against S. aureus and Salmonella spp. The strains isolated from the shrimp showed some resistance to commercially available antibiotics. These data support the use of guava leaf-made medicines in diarrhea cases where access to commercial antibiotics is restricted. In conclusion, guava leaf extracts and essential oil are very active against S. aureus, thus making up important potential sources of new antimicrobial compounds.
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This research aimed to describe the frequency of parasites in stool samples in the environment of Ilha da Marambaia, Rio de Janeiro, Brazil. One hundred and five stool samples were collected and processed by the coproparasitological techniques ethyl acetate sedimentation and centrifuge-flotation using saturated sugar solution. Parasites were detected in 81.9% of the samples, hookworm being the most prevalent, followed by Trichuris vulpis. Ascaris sp. eggs were also found. A high level of evolutive forms of parasites with public health risk was found in stool samples of the environment studied. We propose that health education programs, allied to an improvement of human and animal health care, must be employed to reduce the environmental contamination.
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Pyrethroids are pesticides very used in agriculture, which tend to replace organophosfate and carbamate insecticides. These pesticides have shown to exhibit cardiotoxicity. The aim of this study was to assess if cardiotoxicity is due to direct or indirect effects (metabolites) of permethrin on hearts. There were studies 8 rats; three of them were sacrificed after 24 of the end of treatment with permethrin and the other four were sacrificed after 14 days of the end of treatment. Afterwards hearts and urines were collected. The amounts of permethrin and its main metabolite (3-PBA) were evaluated on hearts and urines of female rats which were treated with permethrin and sacrificed the day after and 14 days after the treatment. Moreover has been highlighted the difference of amount of permethrin and its metabolite between rats sacrificed immediately at the end of treatment and those sacrificed after 14 days. The study of permethrin was accomplished by liquid-liquid extraction and GC-ECD. The evaluation of 3-PBA was performed by SPE procedure with 2-PBA as internal standard and gas-chromatography GC-MS. The concentration of permethrin in hearts is basically the same in 24h and 14 days. The 3-PBA concentration in urines decreased 50 times from 24h to 14 days. In hearts the 3-PBA level also decrease but only 2.24 times and a high variation of results were achieved in rats after 14 days.
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Introduction Sporothrix schenckii is a thermal dimorphic pathogenic fungus causing a subcutaneous mycosis, sporotrichosis. Nitrocoumarin represents a fluorogenic substrate class where the microbial nitroreductase activity produces several derivatives, already used in several other enzyme assays. The objective of this study was the analysis of 6-nitrocoumarin (6-NC) as a substrate to study the nitroreductase activity in Sporothrix schenckii. Methods Thirty-five samples of S. schenckii were cultivated for seven, 14 and 21 days at 35 °C in a microculture containing 6-nitrocoumarin or 6-aminocoumarin (6-AC) dissolved in dimethyl sulfoxide or dimethyl sulfoxide as a negative control, for posterior examination under an epifluorescence microscope. The organic layer of the seven, 14 and 21-day cultures was analyzed by means of direct illumination with 365 nm UV light and by means of elution on G silica gel plate with hexane:ethyl acetate 1:4 unveiled with UV light. Results All of the strains showed the presence of 6-AC (yellow fluorescence) and 6-hydroxylaminocoumarin (blue fluorescence) in thin layer chromatography, which explains the green fluorescence observed in the fungus structure. Conclusion The nitroreductase activity is widely distributed in the S. schenckii complex and 6-NC is a fluorogenic substrate of easy access and applicability for the nitroreductase activity detection.
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RESUMO Tratando-se a asma de uma doença respiratória, desde há várias décadas que tem sido abordada a hipótese de que factores ambientais, nomeadamente os relacionados com a qualidade do ar inalado, possam contribuir para o seu agravamento. Para além dos aeroalergenos, outros factores ambientais como a poluição atmosférica estarão associados às doenças respiratórias. O ar respirado contém uma variedade de poluentes atmosféricos, provenientes quer de fontes naturais quer de origem antropogénica, nomeadamente de actividades industriais, domésticas ou das emissões de veículos. Estes poluentes, tradicionalmente considerados como um problema de foro ambiental, têm sido cada vez mais encarados como um problema de saúde pública. Também a qualidade do ar interior, tem sido associada a queixas respiratórias, não só em termos ocupacionais mas também em exposições domésticas. Dentro dos principais poluentes, encontramos a matéria particulada (como as PM10), o O3, NO2, e os compostos orgânicos voláteis (COVs). Se é verdade que os três primeiros têm como principais fontes de exposição a combustão fóssil associada aos veículos automóveis, já os COVs (como o benzeno, tolueno, xileno, etilbenzeno e formaldeído) são poluentes mais característicos do ar interior. Os mecanismos fisiopatológicos subjacentes à agressão dos poluentes do ar não se encontram convenientemente esclarecidos. Pensa-se que após a sua inalação, induzam um grau crescente de stress oxidativo que será responsável pelo desenvolvimento da inflamação das vias aéreas. A progressão do stress oxidativo e da inflamação, associarse- ão posteriormente a lesão local (pulmonar) e sistémica. Neste trabalho pretendeu-se avaliar os efeitos da exposição individual a diversos poluentes, do ar exterior e interior, sobre as vias aéreas, recorrendo a parâmetros funcionais, inflamatórios e do estudo do stress oxidativo. Neste sentido, desenvolveu-se um estudo de painel na cidade de Viseu, em que foram acompanhadas durante 18 meses, 51 crianças com história de sibilância, identificadas pelo questionário do estudo ISAAC. As crianças foram avaliadas em quatro Visitas (quatro medidas repetidas), através de diversos exames, que incluíram execução de espirometria com broncodilatação, medição ambulatória do PEF, medição de FENO e estudo do pH no condensado brônquico do ar exalado. O estudo dos 8-isoprostanos no condensado brônquico foi efectuado somente em duas Visitas, e o do doseamento de malonaldeído urinário somente na última Visita. Para além da avaliação do grau de infestação de ácaros do pó do colchão, para cada criança foi calculado o valor de exposição individual a PM10, O3, NO2, benzeno, tolueno, xileno, etilbenzeno e formaldeído, através de uma complexa metodologia que envolveu técnicas de modelação associadas a medições directas do ar interior (na casa e escola da criança) e do ar exterior. Para a análise de dados foram utilizadas equações de estimação generalizadas com uma matriz de correlação de trabalho uniforme, com excepção do estudo das associações entre poluentes, 8-isoprostanos e malonaldeído. Verificou-se na análise multivariável a existência de uma associação entre o agravamento dos parâmetros espirométricos e a exposição aumentada a PM10, NO2, benzeno, tolueno e etilbenzeno. Foram também encontradas associações entre diminuição do pH do EBC e exposição crescente a PM10, NO2, benzeno e etilbenzeno e associações entre valores aumentados de FENO e exposição a etilbenzeno e tolueno. O benzeno, o tolueno e o etilbenzeno foram associados com maior recurso a broncodilatador nos 6 meses anteriores à Visita e o tolueno com deslocações ao serviço de urgência. Os resultados dos modelos de regressão que incluíram o efeito do poluente ajustado para o grau de infestação de ácaros do pó foram, de uma forma geral, idênticos ao da análise multivariável anterior, com excepção das associações para com o FENO. Nos modelos de exposição com dois poluentes, com o FEV1 como variável resposta, somente o benzeno persistiu com significado estatístico. No modelo com dois poluentes tendo o pH do EBC como variável resposta, somente persistiram as PM10. Os 8-isoprostanos correlacionaram-se com alguns COVs, designadamente etilbenzeno, xileno, tolueno e benzeno. Os valores de malonaldeído urinário não se correlacionaram com os valores de poluentes. Verificou-se no entanto que de uma forma geral, e em particular mais uma vez para os COVs, as crianças mais expostas a poluentes, apresentaram valores superiores de malonaldeído na urina. Verificou-se que os poluentes do ar em geral, e os COVs em particular, se associaram com uma deterioração das vias aéreas. A exposição crescente a poluentes associou-se não só com obstrução brônquica, mas também com FENO aumentado e maior acidez das vias aéreas. A exposição crescente a COVs correlacionou-se com um maior stress oxidativo das vias aéreas (medido pelos 8-isoprostanos). As crianças com exposição superior a COVs apresentaram maiores valores de malonaldeído urinário. Este trabalho sugere uma associação entre exposição a poluentes, inflamação das vias aéreas e stress oxidativo. Vem reforçar o interesse dos poluentes do ar, nomeadamente os associados a ambientes interiores, frequentemente esquecidos e que poderão ser explicativos do agravamento duma criança com sibilância.-----------ABSTRACT: Asthma is a chronic respiratory disease that could be influenced by environmental factors, as allergens and air pollutants. The air breathed contains a diversity of air pollutants, both from natural or anthropogenic sources. Atmospheric pollution, traditionally considered an environmental problem, is nowadays looked as an important public health problem. Indoor air pollutants are also related with respiratory diseases, not only in terms of occupational exposures but also in domestic activities. Particulate matter (such as PM10), O3, NO2 and volatile organic compounds (VOCs) are the main air pollutants. The main source for PM10, O3, NO2 exposure is traffic exhaust while for VOCs (such as benzene, toluene, xylene, ethylbenzene and phormaldehyde) the main sources for exposure are located in indoor environments. The pathophysiologic mechanisms underlying the aggression of air pollutants are not properly understood. It is thought that after inhalation, air pollutants could induce oxidative stress, which would be responsible for airways inflammation. The progression of oxidative stress and airways inflammation, would contribute for the local and systemic effects of the air pollutants. The present study aimed to evaluate the effects of individual exposure to various pollutants over the airways, through lung function tests, inflammatory and oxidative stress biomarkers. In this sense, we developed a panel study in the city of Viseu, that included 51 children with a history of wheezing. Those children that were identified by the ISAAC questionnaire, were followed for 18 months. Children were assessed four times (four repeated measures) through the following tests: spirometry with bronchodilation test, PEF study, FENO evaluation and exhaled breath condensate pH measurement. 8-isoprostane in the exhaled breath condensate were also measured but only in two visits. Urinary malonaldehyde measurement was performed only in the last visit. Besides the assessment of the house dust mite infestation, we calculated for each child the value of individual exposure to a wide range of pollutants: PM10, O3, NO2, benzene, toluene, xylene, ethyl benzene and formaldehyde. This strategy used a complex methodology that included air pollution modelling techniques and direct measurements indoors (homes and schools) and outdoors. Generalized estimating equations with an exchangeable working correlation matrix were used for the analysis of the data. Exceptions were for the study of associations between air pollutants, malonaldehyde and 8-isoprostanes. In the multivariate analysis we found an association between worsening of spirometric outcomes and increased exposure to PM10, NO2, benzene, toluene and ethylbenzene. In the multivariate analysis we found also negative associations between EBC pH and exposure to PM10, NO2, benzene, ethylbenzene and positive associations between FENO and exposure to ethylbenzene and toluene. Benzene, toluene and ethylbenzene were associated with increased use of bronchodilator in the 6 months prior to the visit and toluene with emergency department visits. Results of the regression models that included also the effect of the pollutant adjusted for the degree of infestation to house dust mites, were identical to the previous models. Exceptions were for FENO associations. In the two-pollutant models, with the FEV1 as dependent variable, only benzene persisted with statistical significance. In the two pollutant model with pH of EBC as dependent variable, only PM10 persisted. 8-isoprostanes were well correlated with some VOCs, namely with ethylbenzene, xylene, toluene and benzene. Urinary malonaldehyde did not present any correlation with air pollutants exposure. However, those children more exposed to air pollutants (namely to VOCs), presented higher values of malonaldehyde. It was found that air pollutants in general, and namely VOCs, were associated with deterioration of the airways. The increased exposure to air pollutants was associated not only with airways obstruction, but also with increased FENO and higher acidity of the airways. The increased exposure to VOCs was correlated with increased airways oxidative stress (measured by 8-isoprostane). Children with higher levels of exposure to VOCs had higher values of urinary malonaldehyde. This study suggests a relation between air pollution, airways inflammation and oxidative stress. It suggests also that attention should be dedicated to air quality as air pollutants could cause airways deterioration.
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SUMMARY In this study, the bioactivity of Talinum paniculatum was evaluated, a plant widely used in folk medicine. The extract from the T. paniculatum leaves (LE) was obtained by percolation with ethanol-water and then subjecting it to liquid-liquid partitions, yielding hexane (HX), ethyl acetate (EtOAc), butanol (BuOH), and aqueous (Aq) fractions. Screening for antimicrobial activity of the LE and its fractions was evaluated in vitro through broth microdilution method, against thirteen pathogenic and non-pathogenic microorganisms, and the antimycobacterial activity was performed through agar diffusion assay. The cytotoxic concentrations (CC90) for LE, HX, and EtOAc were obtained on BHK-21 cells by using MTT reduction assay. The LE showed activity against Serratia marcescens and Staphylococcus aureus, with Minimum Inhibitory Concentration (MIC) values of 250 and 500 µg/mL, respectively. Furthermore, HX demonstrated outstanding activity against Micrococcus luteus and Candida albicans with a MIC of 31.2 µg/mL in both cases. The MIC for EtOAc also was 31.2 µg/mL against Escherichia coli. Conversely, BuOH and Aq were inactive against all tested microorganisms and LE proved inactive against Mycobacterium tuberculosisand Mycobacterium bovisas well. Campesterol, stigmasterol, and sitosterol were the proposed structures as main compounds present in the EF and HX/EtOAc fractions, evidenced by mass spectrometry. Therefore, LE, HX, and EtOAc from T. paniculatumshowed potential as possible sources of antimicrobial compounds, mainly HX, for presenting low toxicity on BHK-21 cells with excellent Selectivity Index (SI = CC90/MIC) of 17.72 against C. albicans.