Artigos Científicos - ICEN

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2557

Navegar

Agora exibindo 1 - 20 de 30

Acesso aberto (Open Access)
Estudo da utilização do extrato aquoso de barbatimão (Stryphnodendron barbatimão, M.) no ensino de química
(1999) PINHEIRO, Marta Helena Tavares; LIMA, Waterloo Napoleão de
In the present work, the pH dependent colour change of the crude vegetal extracts is suggested in teaching chemical or acid-base equilibria, visual indicators and some aspects of spectrophotometric concepts its applications. The extraction methodology proposed is inexpensive and easy to perform in secondary schools and in general chemistry or instrumental undergraduate courses.
Acesso aberto (Open Access)
Potencial herbicida da biomassa e de substâncias químicas produzidas pelo fungo endofítico Pestalotiopsis guepinii
(2008) SANTOS, Lourivaldo da Silva; OLIVEIRA, Marilene Nunes; GUILHON, Giselle Maria Skelding Pinheiro; SANTOS, Alberdan Silva; FERREIRA, Isabel Cristina Serrão; LOPES JÚNIOR, Manoel Leão; ARRUDA, Mara Silvia Pinheiro; SILVA, Milton Nascimento da; SOUZA FILHO, Antonio Pedro da Silva; RODRIGUES FILHO, Edson; OLIVEIRA, Maria da Conceição Ferreira de
Many of the chemical compounds found in nature that are produced by plants or microorganisms can offer new and efficient ways of controlling pests in agriculture and agricultural practice, with the help of fungi. The objective of this work is to characterize the inhibitory potential for seed germination and the plantlet development of two weed species using extracts and compounds obtained from biomass produced by Pestalotiopsis guepinii, an endophytic fungus of the species Virola michelii. The bioassays were developed under controlled conditions at 25 ºC and 12-hour photoperiod for germination, and at 25 ºC and 12-hour photoperiod for root and hypocotyl development. The crude extracts were analyzed at a concentration of 1.0% (m/v). The results showed that the more polar extracts (MeOH-1 and MeOH-2) have the highest inhibitory potential, although the hexane and ethyl acetate extract effects were important, especially for seed germination. Comparatively, weed seed germination was more sensitive to the effects than plantlet development. Mimosa pudica was more affected by the inhibitory effects of the extracts. However, for seed germination of Senna obtusifolia, the extract MeOH-1 showed 100% inhibition. The compounds ergosterol and ergosterol peroxide showed an inhibitory potential always below 35%, not showing the inhibitory potential of the hexane extract from which they were isolated. When these compounds were tested together, little increase was observed in the inhibitory activity.
Acesso aberto (Open Access)
O papel da incerteza no planejamento de sistemas de educação a distância
(2008-08) ELIASQUEVICI, Marianne Kogut; PRADO JÚNIOR, Arnaldo Corrêa
The task of planning a system of distance education (SDE) is a complex process due to the number of components involved, the different views and approaches as to their efficacy, the contending values, the interests at play, and the urgent decisions often needed. This work starts from the experience available in books and articles by the authors, and draws from part of the doctorate thesis of one of them, with the purpose of describing the importance of uncertainty analysis in programs of distance education, thereby contributing to reduce the probability of occurrence of undesirable and/or unexpected events in various situations characterized by complex environments. It describes the trajectory of uncertainty in the perspective of science, and presents a theoretical framework to give support to the problem of planning SDEs. It also mentions the ways in which uncertainties can enter decision processes and the setting up of SDEs, taking as its source a study carried out in the State of Pará. Strategies were devised with a view to improve the articulation of initiatives in the various areas involved, in order to maximize the participation of the different actors and to reinforce the role of distance education as a public policy for social inclusion. In its final considerations, the article emphasizes the applicability of this investigation to other situations. The work aims at contributing to define strategic guidelines for the implementation of SDEs.
Acesso aberto (Open Access)
Efeito fungitóxico in vitro do óleo resina e do óleo essencial de copaíba (Copaifera multijuga Hayne)
(2009) DEUS, Ricardo Jorge Amorim de; CARVALHO, Antonio Sergio Costa; BANNA, Débora Ariane Dornelas da Silva; ARRUDA, Mara Silvia Pinheiro; ALVES, Claudio Nahum; SANTOS, Alberdan Silva
In vitro fungitoxic effect of the oil-resin and the essential oil of copaiba (Copaifera multijuga Hayne). Copaifera multijuga Hayne oil, crude and fractions, was evaluated for its in vitro fungitoxic activities against five species of filamentous fungi belonging to the genus Aspergillus and three yeast species of the genus Candida. Oil-resin and essential oil concentrations ranging from 0.008 mg mL-1 to 1.6 mg mL-1 were used in qualitative and quantitative analyses. Samples were placed onto 5mm-diameter paper disks and distributed on Saboraud culture medium in Petri dishes inoculated with conidia and incubated at 28ºC during 10 days. A solution with 1.6 mg mL-1 of miconazole nitrate was used as positive control. Qualitative results indicated that the oil-resin presented good fungistatic activity; however, one of the essential oil fractions was highly effective against Candida parapsilosis IOC-2882, Aspergillus flavus IOC-3874 and A. tamarii IOC- 187, with inhibition halos of 16.0±1.4 mm, 19.5±2.1 mm and 12.5±3.5 mm, respectively. The quantitative evaluation indicated that 0.3 mg mL-1 of the oil-resin inhibited Aspergillus flavus and Candida parapsilosis growth, whereas 0.08 mg mL-1 of the essential oil fraction reached this same activity.
Acesso aberto (Open Access)
Essential oil composition of Croton palanostigma Klotzsch from north Brazil
(2009) BRASIL, Davi do Socorro Barros; MÜLLER, Adolfo Henrique; GUILHON, Giselle Maria Skelding Pinheiro; ALVES, Claudio Nahum; ANDRADE, Eloisa Helena de Aguiar; SILVA, Joyce Kelly do Rosário da; MAIA, José Guilherme Soares
The essential oils of leaves, twigs, branches, trunk bark and fruits of Croton palanostigma were analyzed by GC and GC-MS. The main compounds found in the oil of the leaves were linalool (25.4%), (E)-caryophyllene (21.0%), methyleugenol (17.2%) and β-elemene (6.0%); in the oil of the twigs were α-pinene (41.4%), limonene (29.0%), sabinene (11.5%) and β-pinene (5.7%); in the oil of the branches were methyleugenol (24.1%), (E)-methylisoeugenol (15.3%), α-pinene (11.2%) and (E)-caryophyllene (8.5%); in the oil of the trunk bark were a-pinene (31.6%), methyleugenol (25.6%) and (E)-methylisoeugenol (23.7%); and in the oil of the fruits were linalool (42.7%), methyleugenol (16.3%) and β-elemene (6.4%). Statistical analysis showed that the leaves and fruit, and the branches and trunk bark, have significant similarities between them. In addition, the trunk bark oil has high brine shrimp larvicidal activity (LC50, 3.71 ± 0.01 mg mL-1).
Acesso aberto (Open Access)
Isolation, X-ray crystal structure and theoretical calculations of the new compound 8-Eepicordatin and identification of others terpenes and steroids from the bark and leaves of Croton palanostigma Klotzsch
(2010) BRASIL, Davi do Socorro Barros; MÜLLER, Adolfo Henrique; GUILHON, Giselle Maria Skelding Pinheiro; ALVES, Claudio Nahum; PERIS, Gabriel; LLUSAR, Rosa; MOLINER, Vicent
Phytochemical studies of the bark and leaves of Croton palanostigma Klotzsch (Euphorbiaceae) led to the isolation of a new clerodane diterpene, 8-epicordatin (2), in addition to 12-oxohardwickiic acid methyl ester (3), aparisthman, cordatin (1), ent-trachyloban-18-oic acid, ent-13-epimanoyl oxide, ent-3-oxo-13-epimanoyl oxide, ent-3β-hydroxy-13-epimanoyl oxide, sitosterol, stigmasterol, stigmastan-3-one, 6β-hydroxystigmast-4-en-3-one, 6β-hydroxystigmasta-4,22-dien-3-one, stigmast-4-en-3-one, stigmasta-4,22-dien-3-one, 3-O-acetylaleuritolic acid, 11α-hydroxyurs-12-en-3-one, α-amyrenone, 24-methylenecycloartenone and lupenone. These compounds were isolated using typical phytochemical procedures and the structures were deduced from spectroscopic studies, including 2D NMR experiments. In addition, the crystalline structure of 8-epicordatin (2) was determined by X-ray diffraction. NMR theoretical calculations at the B3PW91/DGDZVP level were used to confirm the assignment of the chemical shifts of the H-7α and H-7β hydrogens of 8-epicordatin.
Acesso aberto (Open Access)
Synthesis, X-ray crystal structure and theoretical calculations of antileishmanial neolignan analogues
(2010) NASCIMENTO, Josenaide Pereira do; SANTOS, Lourivaldo da Silva; SANTOS, Regina Helena de Almeida; TOZZO, Érica; FERREIRA, Janaina Gomes; CARMO, Maria Carolina Lima do; BRASIL, Davi do Socorro Barros; ALVES, Claudio Nahum
The synthesis and X-ray crystal diffraction structure of two analogues of neolignans, 2-(4-chlorophenyl)-1-phenylethanone (20) and 2-[(4-chlorophenyl)thio]-1-(3,4-dimethoxyphenyl)propan-1-one (12) is described. The compound 12 presents activity against intracellular Leishmania donovani and Leishmania amazonensis amastigotes that cause cutaneous and visceral leishmaniasis. In addition, the density functional theory (DFT) with the B3LYP hybrid functional was employed to calculate a set of molecular descriptors for nineteen synthetic analogues of neolignans with antileishmanial activities. Afterwards, the stepwise discriminant analysis was performed to investigate possible relationship between the molecular descriptors and biological activities. Through this analysis the compounds were classified into two groups active and inactive according to their degree of biological activities, and the more important properties were charges on some key atoms, electronic affinity and ClogP.
Acesso aberto (Open Access)
Biotransformation of sucrose into 5-hydroxy-2-hydroxymethyl-γ-pirone by Aspergillus flavus
(2010-09) FERREIRA, Nelson Rosa; SARQUIS, Maria Inez de Moura; ALVES, Claudio Nahum; SANTOS, Alberdan Silva
The sucrose hydrolysis and the preference of consumption of glucose instead of fructose were investigated for the production of 5-hydroxy-2-hydroxymethyl-γ-pyrone (HHMP) in the presence of Aspergillus flavus IOC 3974 cultivated in liquid Czapeck medium. Standardized 0.5g of pellets were transferred as inoculum into twelve conical flasks of 250 ml containing 100 ml of medium with different sucrose concentration, which was kept at 120 rpm and 28"C for 16 days without pH adjustment. Aliquots of 500μl of the broth culture were withdrawn at 24 h intervals and analyzed. The major yield of HHMP was 26g l-1 in 120g l-1 of sucrose. At these conditions, A. flavus produced an invertase capable of hydrolyzing 65% of total sucrose concentration in 24h, and an isomerase capable of converting fructose into glucose. In this work, it focused the preference for glucose and, then, of fructose by A. flavus and the strategy used to produce HHMP.
Acesso aberto (Open Access)
Composição química e valor nutricional para grandes herbívoros das folhas e frutos de Aninga (Montrichardia linifera, Araceae)
(Instituto Nacional de Pesquisas da Amazônia, 2010-12) AMARANTE, Cristine Bastos do; MÜLLER, Regina Celi Sarkis; DANTAS, Kelly das Graças Fernandes; ALVES, Claudio Nahum; MÜLLER, Adolfo Henrique; PALHETA, Dulcidéia da Conceição
The aninga (Montrichardia linifera, Araceae) is often found in the floodplain ecosystems of the Amazon and is the natural diet of animals such as manatees, turtles, fish, buffalo and cattle. Aiming to contribute to the chemical knowledge and nutritional value of this plant, leaves and fruits of M. linifera were collected on the banks of the Guama and Maratauira rivers, Para State, Brazil. We determined the moisture content, ash mineral composition, lipids, protein, fiber, carbohydrate and caloric value of the fruits and leaves. The mineral composition (Ca, Mg, Cu, Fe, Zn and Mn) was obtained by flame atomic absorption spectrometry. The leaves and the fruits of M. linifera had caloric values of 289.75 kcal and 355.12 kcal, respectively; and a low protein concentration, 0.44% for leaves and 0.24% for fruits. Manganese concentrations were 3279.46 mg kg-1 for leaves and 18151.53 mg kg-1 for fruits. These Mn concentrations are considered toxic, as they exceed the maximum tolerable for the ruminants (1000 mg kg-1). The M. linifera has the capacity to absorb and bioaccumulate large amounts of Ca, Mg and Mn in the soil, which makes it inappropriate for exclusive use as food for turtles, cattle and buffaloes, requiring more studies for its application as part of the diet.
Acesso aberto (Open Access)
Maintenance of syntenic groups between Cathartidae and Gallus gallus indicates symplesiomorphic karyotypes in new world vultures
(2011) TAGLIARINI, Marcella Mergulhão; O'BRIEN, Patricia C.M.; FERGUSON-SMITH, Malcolm A.; OLIVEIRA, Edivaldo Herculano Correa de
Similarities between New World and Old World vultures have been interpreted to reflect a close relationship and to suggest the inclusion of both in Accipitridae (Falconiformes). However, deeper analyses indicated that the placement of the New World vultures (cathartids) in this Order is uncertain. Chromosome analysis has shown that cathartids retained a karyotype similar to the putative avian ancestor. In order to verify the occurrence of intrachromosomal rearrangements in cathartids, we hybridized whole chromosome probes of two species (Gallus gallus and Leucopternis albicollis) onto metaphases of Cathartes aura. The results showed that not only were the syntenic groups conserved between Gallus and C. aura, but probably also the general gene order, suggesting that New World vultures share chromosomal symplesiomorphies with most bird lineages.
Acesso aberto (Open Access)
Avaliação do efeito antifúngico do óleo resina e do óleo essencial de copaíba (Copaifera multijuga Hayne)
(2011) DEUS, Ricardo Jorge Amorim de; ALVES, Claudio Nahum; ARRUDA, Mara Silvia Pinheiro
Copaifera multijuga Hayne oil in natura and its fractions were evaluated as to their fungitoxic activities against five filamentous fungus species belonging to the genus Aspergillus and three yeast species of the genus Candida. Oleoresin and essential oil concentrations ranging from 0.08 mg mL-1 to 1.6 mg mL-1 were used for qualitative and quantitative analyses. The samples were placed onto 5mm-diameter paper discs distributed on Sabouraud's medium in Petri dishes inoculated with spores of the microorganisms and incubated at 28ºC for 10 days. A solution containing 1.6 mg mL-1 miconazole nitrate was used as positive control. Qualitative results showed that the oleoresin presented good activity, while a fraction of the essential oil was highly effective against Candida parapsilosis IOC-2882, Aspergillus flavus IOC-3874 and A tamarii IOC-187 with 16.0±1.4 mm, 19.5±2.1 mm and 12.5±3.5 mm inhibition halos, respectively. The quantitative evaluation showed that 0.3 mg mL-1 oleoresin inhibited the growth of Aspergillus flavus and Candida parapsilosis, while 0.08 mg mL-1 of the essential oil fraction reached this same activity.
Acesso aberto (Open Access)
Novel anthraquinone derivatives produced by Pestalotiopsis guepinii, an endophytic of the medicinal plant Virola michelii (Myristicaceae)
(2011-05) OLIVEIRA, Marilene Nunes; SANTOS, Lourivaldo da Silva; GUILHON, Giselle Maria Skelding Pinheiro; SANTOS, Alberdan Silva; FERREIRA, Isabel Cristina Serrão; LOPES JÚNIOR, Manoel Leão; ARRUDA, Mara Silvia Pinheiro; MARINHO, Andrey Moacir do Rosário; SILVA, Milton Nascimento da; RODRIGUES FILHO, Edson; OLIVEIRA, Maria da Conceição Ferreira de
A new anthraquinone derivative, named guepinone (1), along with the known substances isosulochrin (2) and chloroisosulochrin (3), were isolated from a rice culture of Pestalotiopsis guepinii, an endophytic fungus of Virola michelii. The compounds were identified by analysis of 1D and 2D NMR and MS spectral data. The antimicrobial activity of these compounds was evaluated and chloroisosulchrin (3) was the most active.
Acesso aberto (Open Access)
Assessment of surface water in two Amazonian rivers impacted by industrial wastewater, Barcarena City, Pará State (Brazil)
(2011-08) LIMA, Marcelo de Oliveira; SANTOS, Elisabeth Conceição de Oliveira; JESUS, Iracina Maura de; MEDEIROS, Adaelson Campelo; FAIAL, Kelson do Carmo Freitas; ALVES, Claudio Nahum
In 2007, surface waters were collected from 21 sampling points in Barcarena City in Northern Region of Brazil: one sampling point located in a stream that receives discharge of wastewater from a kaolin processing industry and flows into the Curuperê River, three sampling points located near sources that emerge on the left bank and flow into the Curuperê River, nine sampling points in Curuperê River, which flows into the Dendê River, and eight in Dendê River, a tributary on the right bank of the Pará River. For all water samples were quantified 14 physicochemical variables and levels of 12 metals. The results in the points near the sources of the Curuperê River presented physicochemical profile and metal levels which are typical of surface waters being used as reference to compare and identify possible changes in the chemical characteristics of the other sampling points. The comparison between the results obtained for the sources of the Curuperê River and the ones for the point near the discharge of industrial wastewater revealed strong changes in the values of 6 physicochemical variables (pH, electrical conductivity (EC), total dissolved solids (TDS), sulfate (SO4), ammoniacal nitrogen (NH4-N) and salinity) and an increase in magnitude of the levels of four metals (Al, Fe, Mn and Zn). These facts characterized that the wastewaters were discharged into the environment without adequate treatment. Results in other sampling sites showed that these anomalous conditions were also found along the Curuperê and Dendê Rivers, especially during low tide. This chemical characterization of the waters allowed to identify harmful conditions to aquatic ecosystems and potential health risk for the local people, who use the rivers for drinking water, recreation and transportation.
Desconhecido
Novel technique for locating an intruder in 3D environments by using a cooperative system of multistatic radars
(2011-12) ARAÚJO, Josivaldo de Souza; OLIVEIRA, Rodrigo Melo e Silva de; SOUZA SOBRINHO, Carlos Leônidas da Silva
The aim of this work is to present a new methodology, based on vector and geometrical techniques, for determining the position of an intruder in a residence (3D problem). Initially, modifications in the electromagnetic responses of the environment, caused by movements of the trespasser, are detected. It is worth mentioning that slight movements are detected by high frequency components of the used pulse. The differences between the signals (before and after any movement) are used to define a sphere and ellipsoids, which are used for estimating the position of the invader. In this work, multiple radars are used in a cooperative manner. The multiple estimates obtained are used to determine a mean position and its standard deviation, introducing the concept of sphere of estimates. The electromagnetic simulations were performed by using the FDTD method. Results were obtained for single and double floor residences.
Desconhecido
Flavonoids from the leaves of Deguelia utilis (Leguminosae): structural elucidation and neuroprotective properties
(2012-10) OLIVEIRA, Dalglish Gomes de; ALMEIDA, Cecília M. C. de; SILVA, Consuelo Yumiko Yoshioka e; ARRUDA, Mara Silvia Pinheiro; ARRUDA, Alberto Cardoso; LOPES, Dielly Catrina Favacho; YAMADA, Elizabeth Sumi; COSTA, Edmar Tavares da; MARTINS FILHO, Arnaldo Jorge; SILVA, Milton Nascimento da
Five new flavonoids, 5,3'-dihydroxy-4'-methoxy-2'',2''-dimethylchromene-(5'',6'':6,7)dihydroflavonol (1), 5,3'-dihydroxy-7,4'-dimethoxy-6,8-dimethylallyl-dihydroflavonol (2), 5,3'-dihydroxy-4'-methoxy-8-allyl-2'',2''-dimethylchromene-(5'',6'':6,7) flavanone (3), 5,3'-dihydroxy-7,4'-dimethoxy-6,8-dimethylallyl-flavanone (4), 3,5,3'-trihydroxy-7,4'-dimethoxy6,8-dimethylallyl-flavanol (5), together with the stilbenes 4-methoxylonchocarpene (6) and lonchocarpene (7) were isolated from the leaves of Deguelia utilis. Their chemical structures were established on the basis of NMR (nuclear magnetic resonance) spectral data and HRESITOF-MS (electrospray ionization-high resolution time-of-flight mass spectrometry). Also, in order to investigate potential cytoprotective effects of these flavonoids, we used a fraction eluted with hexane:EtOAc containing all seven flavonoids, in an in vitro model of neurodegeneration, using hippocampal primary cultures from neonatal (PND2-P3) rats exposed to rotenone, a mitochondrial complex I inhibitor. There was a significant reduction in cell viability (19.4 ± 1.6%) when the cultures were exposed to 30 nmol L-1 rotenone for 72 h. Concomitant exposure of the cultures to the FR3 (5 µg mL-1) and 30 nmol L-1 rotenone resulted in values of cell viability similar to control groups (99.6 ± 4.8%), strongly suggesting a cytoprotective effect for this flavonoid-rich fraction.
Desconhecido
Ecofisiologia de plantas jovens de mogno-africano submetidas a deficit hídrico e reidratação
(2013-01) ALBUQUERQUE, Marcos Paulo Ferreira de; MORAES, Fabrícia Kelly Cabral; SANTOS, Rodolfo Inacio Nunes; CASTRO, Gledson Luiz Salgado de; RAMOS, Edson Marcos Leal Soares; PINHEIRO, Hugo Alves
The objective of this work was to evaluate the capacity of young plants of African mahogany (Khaya ivorensis) to recover their water status and gas exchange after water deficit. Plants with approximately 315 days, irrigated (control) and non-irrigated, were evaluated after water was withheld for 14 days, and after one, three, and seven days of irrigation resumption (rehydration). On day 14, the predawn leaf water potential (Ψam) of stressed plants was reduced to -2.66 MPa. With water deficit, significant decreases were observed in predawn relative water content (32% reduction), in net assimilation rate of CO2 (90%), in stomatal conductance (95%), in transpiration (93%), and in intercellular to ambient ratio of CO2 concentration (37%). During rehydration, the water status of stressed plants was recovered after three days. Gas exchange was also recovered, but in a slower rate than water status. Under water deficit, proline concentration increased and total soluble carbohydrate concentration decreased. Young African mahogany plants are tolerant to moderate water deficit.
Desconhecido
Estudo do crescimento de nanofitas de céria dopada com gadolínio por sistema de aquecimento por micro-ondas
(2013-09) GONÇALVES, Rosana de Fátima; CASTRO, D. A.; SANTOS, Maria Rita de Cássia; FIGUEIREDO, Alberthmeiry Teixeira de; BARRADO, Cristiano Morita; LEITE, Edson Roberto; GODINHO JÚNIOR, Mario
Cerium oxide (ceria) has attracted attention because of its important applications such as solid oxide fuel cells, catalysts for automobile exhaust gas, catalysts to obtain hydrogen, UV blockers, biomaterials, etc.. Control methods for synthesis of ceria are of great importance to explain or predict these properties. Thus, the objective of this work was to study the growth of cerium oxide nanobelts in a microwave-assisted hydrothermal system, where in 8 min 330 nm nanobelts were obtained at 130 ºC and 3 atm. The results collaborate to the research on reformers for ethanol and/or solid oxide fuel cells anode.
Desconhecido
New isoflavones from the leaves of Vatairea guianensis Aublé
(2013-11) SOUZA, Ronilson Freitas de; MARINHO, Victor Hugo de Souza; SILVA, Geilson Alcantara da; COSTA JUNIOR, Livio Martins; SILVA, Joyce Kelly do Rosário da; BASTOS, Gilmara de Nazareth Tavares; ARRUDA, Alberto Cardoso; SILVA, Milton Nascimento da; ARRUDA, Mara Silvia Pinheiro
Four isoflavones were isolated from Vatairea guianensis Aublé leaves and identified as 5,3'-dihydroxy-4'-methoxy-2",2"-dimethylpyrano-(5",6":8,7)-isoflavone ( 1: ), 5,7-dihydroxy-3',4'-methylenedioxy-8-prenyl-isoflavone ( 2: ), 5,3'-dihydroxy-4'-methoxy-7-O-β-glucopyranoside-8-prenyl-isoflavone ( 3: ) and derrone ( 4: ) together with five triterpenes identified in mixture, lupeol, α-amyrin, β-amyrin, germanicol and betulinic acid. Substances 1: 3: are novel natural products, although 1: and 2: have been cited as synthetic products. However, all these compounds are first reported from this species. Their chemical structures were elucidated based on their 1D and 2D nuclear magnetic resonance (NMR) data and high resolution mass spectrometry. The ethanol extract from the leaves and 1: 3: were evaluated for their potential in scavenging DPPH• (2,2-diphenyl-1-picrylhydrazylradical) and the results showed that the extract presented high activity (IC50 = 6.2 ± 0.4 µg mL-1), while the isolated compounds showed low antioxidant power (IC50 ≥ 29.5 ± 2.5 µg mL-1) when compared to Trolox (IC50 = 4.5 ± 0.4 µg mL-1).
Desconhecido
Influência da exploração florestal de impacto reduzido sobre as fases de desenvolvimento de uma floresta de terra firme, pará, brasil
(Universidade Federal do Pará, 2013-12) FRANCEZ, Luciana Maria de Barros; CARVALHO, João Olegário Pereira de; BATISTA, Fábio de Jesus; JARDIM, Fernando Cristóvam da Silva; RAMOS, Edson Marcos Leal Soares
The influence of reduced impact logging were evaluated on the growth phases of a terra firme forest in the Paragominas region, state of Pará, that was logged considering two intensities of timber harvesting. Data were collected in 36 permanent sample plots (0.25ha) randomly distributed among treatments (T1 – Logged forest, harvesting the stem of commercial trees; T2 – Logged forest, harvesting the stem and coarse woody debris) and control (T0 unlogged forest). Three growth phases of the forest were considered: mature (DBH > 40cm); building forest (10cm < DBH < 40cm); and gaps (occurrence of a canopy gap and a few or no tree with DBH > 10cm). The homogeneity of variances of sub-plots between treatments, growth phases and years was tested by the Bonferroni test, according to the statistics of Bartlett and Levene. An analysis of variance was applied on the number of sub-plots by phases, years and treatments at a 0.005 significance level. The Tukey test was applied for analyzing the interaction between the phases and years. Before logging the percentage of growth phases were: 57.0% building forest, 38.9% mature forest and 4.1% canopy gaps. Logging reduced the areas of mature forest and building forest, increasing the number of canopy gaps, but this increase had no statistical difference. One year after logging the area of mature forest (38.4%) and building forest (53.1%) increased while the areas of gaps (8.4%) decreased. Three years after logging the percentage of mature forest (37.1%), building forest (57.9%) and gaps (5.0%) were similar to those found before logging. The forest growth phases were not influenced by logging, over the study period. The study forest showed that it is able to grow, closing the canopy gaps, even in a short period of time.
Desconhecido
Improvement of friable callus production of Boerhaavia paniculata Rich and the investigation of its lipid profile by GC/MS
(2014-09) SOUZA, Joanne Moraes de Melo; BERKOV, Strahill; SANTOS, Alberdan Silva
In this study, a protocol to induce high amount of friable callus of Boerhaavia paniculata RICH and a lipidomics technique were applied to investigate the profile of lipids to relate to those present in the roots of this plant that presented anti-inflammatory activity in the crude hexane extract. The callus culture was induced from seeds in solidified Murashige and Skoog medium containing different amounts of glucose and different concentrations of 2,4-Dichlorophenoxyacetic acid. The explants were kept in a germination chamber at 30±2°C with a photoperiod of 16 h under light intensity of 27 µmol m–2 s–1 for 4 weeks. The best results for friable callus formation and development of the biomass were obtained in the treatment containing 2.26 µM 2.4-D and glucose (1.5 %; w/v). Lipidomics techniques were applied in hexane fraction showing higher concentrations of the steroids β-sitosterol (3.53 mg/100 g dc–dry cells), and fatty acids, especially 2-hydroxy-tetracosanoic acid (0.34 mg/100 g dc), eicosanoic acid (86.25 mg/100 g dc), stearic acid (420.83 mg/100 g dc), tetradecanoic acid (10.74 mg/100 g dc) and linoleic acid (100.61 mg/100 g dc). The lipid profile of callus versus that found in the roots of wild plant is described in this work.