Evandro A. Nascimento

Caracterizaçao dos taninos da aroeira-preta (Myracrodruon urundeuva)

This work presents a study on tannins from aroeira-preta (Myracrodruon urundeuva), based on acetone-water (AA) and methanol-water (MA) extracts, in which the contents of total phenols and proanthocyanidins were determined. The total phenols were determined by the Folin-Ciocalteau method and the modified Prussian Blue method. The contents obtained for AA were 19.1 and 24.7% and for MA, 20.2 and 22.8%, respectively by the Folin-Ciocalteau method and the modified Prussian Blue method. The proanthocyanidin contents were determined by the vanillin method, obtaining 2.7% in extract AA and 16.7% in extract MA. No evidence for the presence of antocyanidins and apigedinidins was found, but 3-deoxi-proantocyanidins of the luteolinidin type may be present in the extracts. Fisetin, gallic acid and ellagic acid were detected through high performance liquid chromatography (HPLC). These results show that Myracrodruon urundeuva wood contains a great amount of tannins, which can contribute to its natural durability.

Análise da madeira de Pinus oocarpa parte I: estudo dos constituintes macromoleculares e extrativos voláteis

The chemical composition of Pinus oocarpa wood cultivated in the Brazilian cerrado was established. The obtained results were: a-cellulose (59.05%), hemicelluloses A and B (21.22%), lignin (25.18%), dichloromethane extractives (2.78%), ethanol:toluene extractives (4.38%), hot water extractives (4.31%) and ash (1.26%). The cellulose content was high. This result opens perspectives for using Pinus oocarpa wood in pulp and paper industries. Most of the dichloromethane extractives were diterpenic, palmitic and oleic acids. The volatile composition, obtained by means of the Clevenger method followed by GC-MS analysis was constituted mainly by aromadendrene, ledane, hexadecanal and oleic acid.

TEOR E COMPOSIÇÃO DO ÓLEO ESSENCIAL DE CINCO ACESSOS DE MENTRASTO

This study aimed to analyse the content and the composition of the essential oil of five accesses of mentrasto (Ageratum conyzoides). Five accesses of mentrasto with three repetitions were used. The accesses were obtained in Mariana-MG (AMA), Piranga-MG (API), Visconde do Rio Branco (ARB) and Vicosa-MG (AVB and AVP). The essential oil was obtained by hydrodistillation and the identification of the oil components by CG and GC/MS. The ARB access presented the higher essential oil content, that is 0.70% (P < 0.05). Eleven chemical compounds were identified. The precocene I was the main constituent in the access API, and the precocene II was the main constituent in the accesses AMA, ARB, AVB and AVP.

Studies on polyphenols and lignin of Astronium urundeuva wood

), tambem num soxhlet. Do extrato resultante foi obtida a lignina demadeira moida (MWL). Nao considerando a MWL, a soma de todos os extratos alcancou 18,19%da madeira seca. O conteudo em lignina de Klason de A e o conteudo de grupos metoxila da MWLforam 23,84% e 19,00%, respectivamente. Outra amostra de A apresentou conteudos em polissa-carideos de dificil e facil hidrolise de 34,86% e 18,81%, respectivamente. Uma Segunda amostrade madeira moida foi submetida a uma extracao unica com metanol, a temperatura ambiente,fornecendo o extrato metanolico B (23,85% da madeira seca). Espectros de RMN do

Influence of radiation level on plant growth, yield and quality of essential oil in carqueja

A influencia do nivel de radiância no crescimento da planta, rendimento e qualidade do oleo essencial de Baccharis trimera foi estudado neste trabalho. As plantas foram cultivadas sob 4 niveis de radiância: 100, 60, 50 e 20% durante um periodo de 259 dias. Foram avaliadas, quanto ao comprimento, numero de nos, ramos, diâmetro do caule (altura do colo), acumulo de fitomassa, conteudo e composicao do oleo essencial. O nivel mais elevado de radiacao causou aumento em todas as caracteristicas avaliadas, exceto para o comprimento, que foi reduzido com o aumento na radiacao. O rendimento de oleo essencial tambem aumentou com a elevacao do nivel de radiância.

Analysis of a Brazilian green propolis from Baccharis dracunculifolia by HPLC-APCI-MS and GC-MS

Os extratos em etanol e diclorometano de uma propolis verde de Baccharis dracunculifolia foram analisados por CLAE-ICPA-EM e CG-EM, respectivamente. A tecnica de CLAE-EM-ICPA, no modo positivo, forneceu uma completa e inequivoca composicao quimica da amostra de propolis verde. Ela serve como impressao digital para amostras diferentes de propolis. A composicao do extrato em etanol consistiu fundamentalmente de acido cinâmico e derivados, flavonoides, acido benzoico e alguns benzoatos, aromaticos nao hidroxilados, e acidos e esteres alifaticos, os quais sao normalmente ignorados na literatura porque nao absorvem luz UV. Os constituintes principais do extrato em diclorometano foram compostos prenilados, alcanos e terpenoides.

Um marcador químico de fácil detecção para a própolis de Alecrim-do-Campo (Baccharis dracunculifolia)

In the present work a volatile chemical marker (CM) for the Baccharis dracunculifolia (Bd) propolis is proposed, which is easily detectable by gas chromatography. It is the most abundant volatile compound in dichloromethane extracts of green propolis from this plant, but it appears also, in different concentrations, in dichloromethane extracts of brown, dark and red propolis from regions where Bd grows. The CM is present in significative concentration in the bud extract of Bd, in contrast to the leaf extract where its concentration is low. Propolis from regions without Bd does not contain the CM. This compound was recently isolated; it is the allyl 3-prenylcinnamate. Commercial samples of green propolis ethanol extract were analyzed and the first quality one (exportation standard) presented the highest concentration on CM. This finding makes easier the quality control of green propolis extracts sold at the market.

Chemical constituents of the underground stem bark of Duguetia furfuracea (Annonaceae)

In the present investigation the underground parts of Duguetia furfuracea (Annonaceae) were used to conduct a phytochemical study that included the brine shrimp (Artemia salina) lethality bioassay. The substances (-)-duguetine b-N-oxide, (-)-duguetine, dicentrinone, (-)-N-methyltetrahydropalmatine, and (+)-N-methylglaucine were isolated from the alkaloid extract of the bark of the underground stem, and the ureide allantoin was also isolated by precipitation from the ethanol extract of the wood of the underground stem. A fresh volatile oil and a nonpolar extract were also obtained from the underground stem bark. The substances 2,4,5-trimethoxystyrene, a-gurjunene, aromadendrene, bicyclogermacrene, (E)-methylisoeugenol, and a-asarone were isolated from the fresh volatile oil and polycarpol, b-caryophyllene oxide, 2,4,5-trimethoxystyrene, a-asarone, and asaraldehyde were obtained from the petroleum ether extract. The present study describes for the first time the alkaloid (-)-duguetine b-N-oxide and the occurrence of (-)-N-methyltetrahydropalmatine and (+)-N-methylglaucine in the family Annonaceae. All extracts were active in the brine shrimp lethality bioassay.

Biphenyl Type Lignin Model Compounds: Synthesis and 13C NMR Substituent Chemical Shift Additivity Rule

BiphenylType Lignin Model Compounds: Synthesis and C NMR Substituent Chemical Shift Additivity Rule By Mariza G. Drumond, Dorila PiloVeloso, Stela D. Santos Cota, Sergio A. Lemos de Morais, Evandro A. do Nascimento and Chen-Loung Chen 1 Departamento de Quimica, Institute de Cienias Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil 2 Departamento de Quimica, Universidade Federal de Uberländia, Uberländia, Brazil 3 Department ofWood and Paper Science, North Carolina State University, Raleigh, N.C. 27695-8005, U.S. A.

Composition of the essential oil from the leaves of tree domestic varieties and one wild variety of the guava plant (Psidium guajava L., Myrtaceae)

The compositions of the essential oils from the leaves of three domestic varieties of the guava tree Psidium guajava L. (Paluma, Seculo XXI and Pedro Sato) and of one wild variety were compared. Essential oils were extracted by steam distillation, the components were identified by gas chromatography coupled to mass spectrometry GC-MS, and the apparent concentrations were determined by gas chromatography with a flame ionization detector. The results demonstrated that the three essential oils contained many common substances with a prevalence of 1,8-cineole, whereas the essential oil of the Paluma variety contained 1,8-cineole (42.68%) as the major constituent, as well as α-terpineol (38.68%). The principal components of the essential oil of the Seculo XXI variety were 1,8-cineole (18.83%), trans-caryophyllene (12.08%), and selin-11-en-4-αol (20.98%), while those of the Pedro Sato variety and of the wild plant were 1,8-cineole (17.68%) and (12.83%), caryophyllene oxide (9.34%) and (9.09%), and selin-11-en-4-α-ol (21.46%) and (22.19%), respectively.