Heber dos Santos Abreu

Leishmanicidal effect of LLD-3 (1), a nor-triterpene isolated from Lophanthera lactescens

Leishmanicidal activity of 6alpha, 7alpha, 15beta, 16beta, 24-pentacetoxy-22alpha-carbometoxy-21beta,22beta-epoxy-18beta-hydroxy-27,30-bisnor-3,4-secofriedela-1,20 (29)-dien-3,4 R-olide (LLD-3 (1)) isolated from Lophanthera lactescens Ducke, a member of the Malpighiaceae, was demonstrated against intramacrophage amastigote forms (IC(50) of 0.41mug/mL). The in vitro leishmanicidal effect of Glucantime, the first choice drug for leishmaniasis treatment, was increased by LLD-3 (1) association. The leishmanicidal effect of LLD-3 (1) was not due to stimulation of nitric oxide production by macrophages. LLD-3 (1) was also not cytotoxic for mouse peritoneal macrophages or B cells as assessed by the XTT and Trypan blue exclusion assays. LLD-3 (1) was unable to affect proliferation of naïve or activated B and T cells, as well as the B cells immunoglobulin synthesis. Cellularity of different tissues, liver and kidney functions were not altered in mice treated with LLD-3 (1), as well as the histology pattern of different organs. Our results add LLD-3 (1) as a potential drug candidate for treatment of leishmaniasis.

A supramolecular proposal of lignin structure and its relation with the wood properties

In spite of the great importance of cellulose the lignin is considered the second most abundant substance of the wood. However, little attention has been given it, mainly to wood properties. The lignin as well as other structural compounds (cellulose and hemicelluloses), has obviously an important role on the wood properties, probably due its composition and existent bonds. In general lignins have beta-O-4 (Alkyl Aril Ether) as majoritary bond. This bond in a continued structure form big molecules with spiral conformation as virtual model. Based on this idea, lignins that have high/low beta-O-4 content may have differentiated spiraled structures,suggesting different behaviors on the wood properties,which shows that the lignins (Guaicyl:Syringyl (GS)) of angiosperms, for example, which have higher beta-O-4 content would present higher spiral conformation than gymnosperms lignins(HG). On the other hand HG lignins have chance of being more anchored on the matrix compound than GS lignins. In this context, the beta-O-4 bonds of lignins possibly affect the wood properties, therefore, it is considered relevant for wood technology science discussion.

A nor-triterpenoid from Lophanthera lactescens☆

Abstract A benzene extract of Lophanthera lactescens wood was shown to contain stigmasta-4, 22-dien-3-one, ergost-en-3-one, stigmasterol, ergost-5-en-3-ol, β-amyrenone and a new nor-triterpene. Structural determinations were made from spectrometric data, including 2D NMR experiments.

Efeito da termorretificação nas propriedades físicas e químicas da madeira de Pinus caribaea

Conduziu-se este estudo, com o objetivo de avaliar o efeito da termorretificacao nas propriedades fisicas (densidade aparente, teor de umidade de equilibrio, perda de massa, contracao e inchamento lineares e volumetricos) e na composicao quimica da madeira normal (lado oposto) e de compressao de Pinus caribaea Morelet. Amostras de 25 x 25 x 50 mm foram termorretificadas sob duas temperaturas: 200 e 220 oC. Os resultados indicaram uma reducao no teor de umidade de equilibrio e nos inchamentos e contracoes apos a termorretificacao, independente do tipo de lenho. A madeira de compressao apresentou maior inchamento longitudinal que a madeira normal, entretanto, apos a termorretificacao, as melhorias foram similares entre os dois tipos de lenho. As madeiras termorretificadas a 200 e 220 oC apresentaram perdas de massa de 9,94 e 21,03 %, respectivamente. A termorretificacao promoveu um aumento relativo no teor de lignina e uma reducao nos teores de holocelulose e α-celulose, indicando a ocorrencia de degradacao termica desses componentes.

VARIAÇÃO LIGNO-ANATÔMICA EM MUDAS DE Eucalyptus grandis (Hill ex Maiden) TRATADAS COM REGULADORES DE CRESCIMENTO

Neste trabalho, objetivou-se analisar a relacao dos reguladores de crescimento GA3 e BAP na lignificacao e, consequentemente no diâmetro das fibras de plantas de Eucalyptus grandis aos seis meses de idade. Estudos anatomicos, bioquimicos e geneticos em decorrencia da aplicacao exogena de reguladores de crescimento na fase de desenvolvimento do vegetal, tem sido cada vez mais enfatizados. Alguns desses estudos tem obtido avanco no que se refere a interacao dos hormonios vegetais em relacao a anatomia e ao processo de lignificacao. A aplicacao dos reguladores de crescimento GA3 e BAP foi realizada isoladamente ou combinados nas respectivas concentracoes: GA3 (49,13 µM e 98,26 µM); BAP (111 µM e 222 µM), em mudas de Eucalyptus grandis ate seis meses de idade. Analises quimicas e anatomicas foram realizadas com o segmento caulinar das plantas tratadas. Para quantificar o teor de lignina pelo metodo Klason, as amostras foram livres para a retirada de extrativos e proteinas. Para a mensuracao do diâmetro das fibras, as amostras, apos sua dissociacao, foram analisadas por microscopia otica. O teor de lignina variou entre 23,37 a 29,64% e o diâmetro de fibra variou entre 13,33 a 20,39 µm. Tambem, pelos resultados, foi possivel visualizar, com o tratamento G[1] (49,13 de GA3 com 111µM de BAP) que o teor de lignina reduziu em 21,2% em relacao ao controle, e o C[1] diâmetro de fibra obteve o menor aumento em relacao aos outros tratamentos.

Alterações ligno-anatômicas em Solanum gilo Raddi por aplicação de cálcio e boro como estratégia de defesa

As plantas lenhosas, de maneira geral, possuem alto teor de lignina, podendo alcancar valores entre 25 a 35% em relacao a massa seca. Valores normalmente encontrados nas plantas arboreas. Algumas plantas jovens ou de habitos de crescimentos inferiores aos arbustivos possuem baixo teor de lignina, neste sentido, buscando superar os atuais niveis de lignificacao, foram testados em plantas fatores exogenos de estimulacao. Um sistema enzimatico complexo e responsavel pela formacao biossintetica dos precursores intermediarios da lignina, entretanto as peroxidases sao responsaveis pela fase determinante da polimerizacao na parede celular, cuja atividade foi pressupostamente modificada atraves da aplicacao de calcio e boro, visando aumentar a resistencia da planta aos fatores bioticos e abioticos, entre outros. Para tal, utilizou-se a especie Solanum gilo (familia Solanaceae) cultivar Portugues como planta experimental sob varios tratamentos, monitorando as aplicacoes quinzenal e semanalmente, nas formas simples e multiplas de aplicacao de CaSO4, H3BO3, CaCl2 e H3BO3/CaSO4, CaSO4/CaCl2, CaCl2/ H3BO3 e CaSO4/H3BO3/CaCl 2. O tratamento CaSO4/CaCl2, estatisticamente avaliado, induziu as plantas a uma taxa de lignificacao equivalente ao teor de lignina de 19%, superando a testemunha que apresentou 14 %. Modificacoes anatomicas foram tambem observadas nos elementos de vaso e fibras no que tange ao comprimento, diâmetro e espessura da parede celular. A quantificacao da lignina foi realizada segundo o metodo de Klason. A espectroscopia no infravermelho foi utilizada para analise composicional, revelando a existencia de modificacao da composicao de lignina guaiacilica da planta testemunha (G:S), 1,2:1 para lignina siringilica (G:S), 0,8:1 nas plantas que receberam o tratamento (CaSO4/CaCl2) quinzenal e semanalmente, respectivamente.

Estimativa por Infravermelho da Concentração da Unidade Estrutural β-O-4 em Ligninas de Angiospermas Tropicais

Five Bjorkman lignins, codified as AM, LL, GG, PP and AP, were isolated from wood species of Aspidosperma macrocarpum Mart., Lophanthera lactescens Ducke, Gallesia gorazema (Vell.) Miq., Peltogyne paniculata Bth. and Aspidosperma polyneuron Muell. Arg., respectively. Analyses of the lignins were carried out by Fourier transformed infrared spectroscopy using an experimental technique, Diffusely Reflected Infrared Fourier Transformed (DRIFT), admitting in the original spectra a band at 1500 cm-1 as an internal reference. Application of a deconvolution technique made possible to estimate the percentage per mol of b-O-4 unit content around 65.5% to AM, 68.0% to LL, 71.0% to GG. 73.4% to PP and 75.0% to AP, toward AM

Approach on the integument lignin profile of seeds of Araucaria angustifolia

El objetivo de esta investigacion fue identificar y cuantificar los tipos de lignina, y caracterizar su funcion segun la resistencia fisica aparente de cada capa de la testa de la semilla de Araucaria angustifolia. Cada capa de la semilla (exotesta, mesotesta e endotesta) se molio, homogeneizo y sometio a un ciclo de pre-extraccion con solventes (ciclohexano, acetato de etilo y metanol) para preparar el material para cuantificar la lignina. Tambien se realizo en cada capa de la semilla un pre-tratamiento con NaOH 1 % para cuantificar la lignina y para aplicar espectroscopia infrarroja. El contenido de lignina en la testa fue 32,43 % para las tres capas juntas. Despues del tratamiento alcalino, el contenido de lignina fue de 31,52 % en exotesta, 16,88 % en mesotesta y 15,32 % en endotesta. Lignina dioxano se aislo del tegumento de la semilla y la misma se redujo quimicamente con NaHB4 . Los espectros infrarrojos se registraron a partir de lignina dioxano, lignina dioxano reducida y de lignina de Klason de cada capa con tratamiento alcalino. Se realizaron analisis microscopicos de las capas de exotesta y mesotesta de la testa de la semilla al natural, por prueba histoquimica (prueba Wiesner) y por microscopia de fluorescencia. El analisis infrarrojo permitio observar la presencia de terminales aldehido en lignina dioxano y trazar el perfil estructural de las ligninas de Klason en capas diferentes. En el analisis microscopico con fluorescencia se identifico en la exotesta la presencia de macroesclereidas altamente lignificadas

Antinociceptive and Anti-inflammatory Activities of the Methanolic Extract from the Stem Bark of Lophanthera lactescens.

Lophanthera lactescens is a medicinal plant commonly used in traditional medicine to relieve fever and pain in inflammatory processes. In the present study, the in vivo antinociceptive and anti-inflammatory effects of the methanolic extract from L. lactescens have been investigated. Antinociceptive activity was evaluated through writhing, formalin, and tail flick tests, while the anti-inflammatory activity was evaluated through paw oedema and air pouch tests in mice. A phytochemical analysis was performed. The extract produced significant inhibition on nociception induced by acetic acid-induced abdominal writhing, formalin, and tail flick tests, and on inflammation induced by oedema and air pouch tests. The previous administration of atropine and glibenclamide reduced the antinociceptive effect produced by the methanolic extract from L. lactescens on the tail flick test in 89% and 66%, respectively. The methanolic extract had no significant effect in the open field test. No intoxication symptoms were observed in the animals administered orally at increasing doses up to 2000 mg/kg. The methanolic extract from the stem bark of L. lactescens possesses antinociceptive properties on models of acute pain induced by chemical and thermal stimuli as well as in models of inflammation and further suggests that this anti-inflammatory activity might involve inhibition of the proinflammatory cytokines, and the antinociceptive activity might involve participation of the cholinergic system and adenosine triphosphate-dependent K+ channel.

LIGNIFICAÇÃO E CRESCIMENTO DE Eucalyptus grandis (HILL EX MAIDEN) COM GA3 E BAP

In this research experiments were accomplished with two classes of vegetable hormones (gibberellin and cytokinin); with the objective of verifying the effect of gibberellic acid and 6-Benzylaminopurine (GA 3 and BAP) on the lignification and the longitudinal growth in seedlings of Eucalyptus grandis . The experiment was accomplished greenhouse, where were the growth regulators combined or isolated applied, in the following concentrations: GA 3 (49.13 μM e 98.26 μM); BAP (111 μM e 222 μM), with five repetitions for each treatment. The comparisons among the averages of the height of the plants to the 6 months showed that the most pronounced prolongations of the stem corresponded to the treatments G [2] , G [2] C [1] and G [2] C [2] where the largest concentration of GA 3 was used. In the treatment G [1] C [1] where it was combined to smallest concentration of GA 3 with to smallest concentration of BAP (49,13 μM de GA 3 + 111 μM de BAP), it happened the smallest lignin tenor 23,37%.