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Eight new diterpenoids isolated from Pterodon ernarginatus Vog. have been assigned the following structures and stereochemistry: 6a,7~-diacetoxyvouacapane (1 ), 7p-acetoxyvouacapane (3), 6a,7~-dihydroxyvouacapan-l7~-oic acid (1 1 ), methyl 61~.7~-dihydroxyvouacapan-l7~-oate (1 2). methyl 7~-acetoxy-6a-hydroxyvouacapan-l7~oate (1 4). 6a-acetoxyvouacapano-17~,7~-lactone (I 6). vouacapane-6a,7~,14~-triol (25). and 6a,7p-diacetoxyvouacap-I 4(17) -ene (24). Compound (24) was hydrogenated (Pd-C) to 6a,7~-diacetoxy-l4-epi-vouacapane (20). The same 14-epi-diacetate (20) was obtained by reduction with lithium aluminium hydride of the 17-tosylate (1 8) derived from vouacapane-6a-7~,17-triol (1 7). 7fi-Acetoxyvouacapane (3) has been converted into the parent furohydrocarbon [vouacapane (6)] by Wolff-Kishner reduction of the derived vouacapan-7-one (5). N.m.r. and mass spectra of several compounds are described. Brasllia-DF, BrazilTHE oil from the fruits of Pterodon pubescens Benth., P. emarginatus Vog., and P. PoligalaeJlorus Benth., has protective action 1 against infection by cercaria of Schistosoma mansoni. We are engaged in a chemical study of P. emarginatm and P. ~oligalaeJlorus, and have recently reported preliminary results on the structure and stereochemistry of several diterpenoids isolated from the former.2 We now describe the structure of two more such compounds [( 24) and ( 25)] obtained from the same source, and give the details of our previous work.The structures of 6a,7 p-diacetoxyvouacapane (1) and 7 fbacetoxyvouacapane (3) were mainly derived from n.m.r. evidence (60, 100, and 220 M H z ) . ~~ Apart from the easily recognized CMe, OAc, and furan a-and Pproton signals, these compounds show characteristic CH*OAc absorption which helps to assign the stereochemistry at positions 5-43. Thus the two CH.OAc systems at C-6 and C-7 in compound (1) appear as two ABX quartets at 6 5.24 and 4-85 p.p.m., respectively, with J A B 9.0, J A X 11.5, and J ~x , 10 Hz, showing that the four protons at C-5, C-6, C-7, and C-8 all occupy axial positions. In the case of the monoacetate (3), the only such proton appears as a doubly split ( J 5.5 Hz) triplet ( J 10.5 Hz) at 6 4-75 p.p.m. Our assignment of this equatorial acetate to C-7 was confirmed 2b by comparison of this signal with the C-6 proton signals from (22) (6 5-42), and the 6a,l7-diacetoxy-'lp-hydroxycompound (23) ( 6 5.24).3The stereochemical assignment at C-14 was derived from 220 MHz spectra of compounds ( 1) and (3),2a where the C-14 proton appears as a quintet showing equal coupling ( J 6.5 Hz) with the C-14 methyl group and the C-8 axial proton, and thus revealing its cis relationship to the latter.The monoacetate (3) was related to vouacapane (6) by Wolff-Kishner reduction of the derived ketone (5); a mixture of two isomeric furohydrocarbons was obtained owing to epimerization at C-8. One of the components, m.p. 78-79' , was identical with the furohydrocarbon prepared by King et aZ.* Attempts to convert the mono-ol(4) into the corresponding tosylate and to reduc...

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 β-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 β-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 β-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 β-O-4 bonds of lignins possibly affect the wood properties, therefore, it is considered relevant for wood technology science discussion.

RESUMOAs plantas lenhosas, de maneira geral, possuem alto teor de lignina, podendo alcançar valores entre 25 a 35% em relação a massa seca. Valores normalmente encontrados nas plantas arbóreas. Algumas plantas jovens ou de hábitos de crescimentos inferiores aos arbustivos possuem baixo teor de lignina, neste sentido, buscando superar os atuais níveis de lignificação, foram testados em plantas fatores exógenos de estimulação. Um sistema enzimático complexo é responsável pela formação biossintética dos precursores intermediários da lignina, entretanto as peroxidases são responsáveis pela fase determinante da polimerização na parede celular, cuja atividade foi pressupostamente modificada através da aplicação de cálcio e boro, visando aumentar a resistência da planta aos fatores bióticos e abióticos, entre outros. Para tal, utilizou-se a espécie Solanum gilo (família Solanaceae) cultivar Português como planta experimental sob vários tratamentos, monitorando as aplicações quinzenal e semanalmente, nas formas simples e múltiplas de aplicação de CaSO 4 , H 3 BO 3 , CaCl 2 e H 3 BO 3 /CaSO 4 , CaSO 4 /CaCl 2 , CaCl 2 / H 3 BO 3 e CaSO 4 /H 3 BO 3 /CaCl 2 . O tratamento CaSO 4 /CaCl 2 , estatisticamente avaliado, induziu às plantas a uma taxa de lignificação equivalente ao teor de lignina de 19%, superando a testemunha que apresentou 14 %. Modificações anatômicas foram também observadas nos elementos de vaso e fibras no que tange ao comprimento, diâmetro e espessura da parede celular. A quantificação da lignina foi realizada segundo o método de Klason. A espectroscopia no infravermelho foi utilizada para análise composicional, revelando a existência de modificação da composição de lignina guaiacílica da planta testemunha (G:S), 1,2:1 para lignina siringílica (G:S), 0,8:1 nas plantas que receberam o tratamento (CaSO4/CaCl 2 ) quinzenal e semanalmente, respectivamente.Termos para indexação: Lignina, Solanum gilo, peroxidase. ABSTRACTNormally woody plants present high lignin content, even overcoming 35% from dry weight. Such values are almost found in arboreal plants. However, young plants or plants with lower growth form than tree show low lignin content. In this term, current levels of lignification could be increased by exogenous factor of stimulation. There are complex enzymatic systems responsible for the lignin intermediary precursors formation, however, the peroxidases enzymes have been pointed out as responsible for the lignin polymerization in the cellular wall, whose activity was modified supposedly by calcium and boron application, seeking to increase the plant resistance to the biotic and non biotic factors. The Solanum gilo (Solanaceae family), (Portuguese cultivars) was used as experimental plant according to the several treatments, installed twice (15 days) and once (7 days) for month, in the simple and multiple form to CaSO4, H 3 BO 3 , CaCl 2 and H 3 BO 3 /CaSO 4 , CaSO 4 /CaCl 2 , CaCl 2 /H 3 BO 3 and CaSO 4 /H 3 BO 3 /CaCl 2 treatments, respectively. The treatment (CaSO 4 /CaCl 2 ) appraised statistically...

Neste trabalho, objetivou-se analisar a relação dos reguladores de crescimento GA3 e BAP na lignificação e, consequentemente no diâmetro das fibras de plantas de Eucalyptus grandis aos seis meses de idade. Estudos anatômicos, bioquímicos e genéticos em decorrência da aplicação exógena de reguladores de crescimento na fase de desenvolvimento do vegetal, têm sido cada vez mais enfatizados. Alguns desses estudos têm obtido avanço no que se refere à interação dos hormônios vegetais em relação à anatomia e ao processo de lignificação. A aplicação dos reguladores de crescimento GA3 e BAP foi realizada isoladamente ou combinados nas respectivas concentrações: GA3 (49,13 µM e 98,26 µM); BAP (111 µM e 222 µM), em mudas de Eucalyptus grandis até seis meses de idade. Análises químicas e anatômicas foram realizadas com o segmento caulinar das plantas tratadas. Para quantificar o teor de lignina pelo método Klason, as amostras foram livres para a retirada de extrativos e proteínas. Para a mensuração do diâmetro das fibras, as amostras, após sua dissociação, foram analisadas por microscopia ótica. O teor de lignina variou entre 23,37 a 29,64% e o diâmetro de fibra variou entre 13,33 a 20,39 µm. Também, pelos resultados, foi possível visualizar, com o tratamento G[1] (49,13 de GA3 com 111µM de BAP) que o teor de lignina reduziu em 21,2% em relação ao controle, e o C[1] diâmetro de fibra obteve o menor aumento em relação aos outros tratamentos.

RESUMONesta pesquisa foram realizados experimentos com duas classes de hormônios vegetais (giberelina e citocinina); com o objetivo de verificar o efeito do ácido giberélico e 6-benzilaminopurina (GA 3 e BAP) sobre a lignificação e o crescimento longitudinal em mudas de Eucalyptus grandis. O experimento foi realizado em casa de vegetação, na qual foram aplicados os reguladores de crescimento combinados ou isolados, nas seguintes concentrações: GA 3 (49,13 μM e 98,26 μM); BAP (111 μM e 222 μM), com cinco repetições para cada tratamento. As comparações entre as médias da altura das plantas aos 6 meses mostraram que os alongamentos mais pronunciados do caule corresponderam aos tratamentos com a maior concentração de GA 3. No tratamento em que foi combinada a menor concentração de GA 3 com a menor concentração de BAP (49,13 μM de GA 3 + 111 μM de BAP), ocorreu o menor teor de lignina 23,37%. Palavras-chave: Eucalyptus grandis; parede celular; lignina; biotecnologia florestal. ABSTRACTIn 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%.

Callogenesis was achieved using growth regulators at different concentrations to obtain the best characteristics regarding the calluses texture aspect with the main objective to produce friable calluses from stem explants of Eucalyptus grandis. Stem segments of approximately 1 cm were excised from 30-day seedlings. The treatments were prepared based on the MS medium added with TDZ alone or combined with AIA; 2,4-D; ANA. Each treatment consisted of five repetitions with five explants per plate. After 210 days of in vitro culture, the calluses were evaluated visually and by manipulation for texture. The explants that did not produce calluses were those exposed to treatments with 2,4-D 50.0 µM; TDZ 3.0 µM and in absence of a growth regulator (control).The best protocols for maintenance of friable calluses of stem explants of Eucalyptus grandis under the conditions performed in this work were those using only TDZ. Keywords

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