oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 5 )

2019 ( 440 )

2018 ( 551 )

2017 ( 509 )

Custom range...

Search Results: 1 - 10 of 345303 matches for " Fern?o C.;Oliveira "
All listed articles are free for downloading (OA Articles)
Page 1 /345303
Display every page Item
Cytotoxicity of Wedelia paludosa D.C. extracts and constituents
Batista, Ronan;Brand?o, Geraldo C.;Braga, Ferno C.;Oliveira, Alaíde B.;
Revista Brasileira de Farmacognosia , 2009, DOI: 10.1590/S0102-695X2009000100009
Abstract: wedelia paludosa d.c. (asteraceae) is an ornamental species occurring in many regions of brazil. aiming to find new cytotoxic compounds, the hydromethanol extract of w. paludosa (hme), as well as the dichloromethane (df) and water (wf) fractions resulting from its partition, were submitted to the brine shrimp lethality bioassay (bslb) in order to evaluate their cytotoxicity. dichloromethane fraction (df) was shown to be the most cytotoxic fraction (lc50 = 140.6 μg/ml), and its analysis by reversed phase high performance liquid chromatography (rp-hplc) revealed ent-kaurenoic (1, 6.22 ± 0.23%) and grandiflorenic (2, 3.22 ± 0.31%) acids as important constituents. hme (lc50 = 980 μg/ml), df (lc50 = 140.6 μg/ml), 1 (lc50 = 15.9 μg/ml) and 2 (lc50 = 29.8 μg/ml) were found to be cytotoxic, while the water fraction (wf, lc50 >> 1000 μg/ml) was inactive. as conclusion, the cytotoxicity observed for hme and df is mainly due to the presence of 1 and 2 in their constitution.
Constituents from Maytenus ilicifolia leaves and bioguided fractionation for gastroprotective activity
Leite, Jo?o Paulo V.;Braga, Ferno C.;Romussi, Giovanni;Persoli, Rita M.;Tabach, Ricardo;Carlini, Elisaldo A.;Oliveira, Alaíde B.;
Journal of the Brazilian Chemical Society , 2010, DOI: 10.1590/S0103-50532010000200009
Abstract: maytenus ilicifolia mart. ex reissek is traditionally used in brazil for treatment of gastric ulcers. here we report the phytochemical investigation of an ethanol extract of m. ilicifolia leaves (eemil) aiming at the isolation of constituents which were used as chemical markers to monitor an activity-guided fractionation of a lyophilized aqueous extract of m. ilicifolia leaves (laemil). from eemil, four flavonoids were isolated, namely the tri-flavonoid glycosides mauritianin (1), trifolin, (2) hyperin (4), and epi-catechin (5). fractionation of laemil led to 5 fractions which afforded the tetra-glycoside kaempferol derivative (3), and galactitol (6). laemil and its fractions were evaluated in rats for their effects on gastric secretion volume and ph. hplc (high performance liquid chromatography) analysis revealed that only fractions containing the tri- and tetra-flavonoid glycosides 1 and 3 caused significant increase of gastric volume and ph, thus indicating that these glycosides play an important role on the gastroprotective effect of m.ilicifolia leaves.
Simpatia e sociabilidade no pensamento de Hume
Ferno de Oliveira Salles
DoisPontos , 2010,
Abstract: The purpose of this text is to show, in general terms, the main aspects of Hume’s critic of those philosophers that he called by the epithet of “modern epicureans”. Hobbes, and his supposed followers, according to Hume’s point of view, made the mistake of choosing self love as the source and principle of all our actions and judgments. After that, we intend to outline the central role of the concept of sympathy in this critic and in the constitution of Hume’s moral theory.
Biotransformation of digitoxigenin by Fusarium ciliatum
Pádua, Rodrigo M.;Oliveira, Alaíde B.;Souza Filho, José D.;Vieira, Géssy J.;Takahashi, Jacqueline A.;Braga, Ferno C.;
Journal of the Brazilian Chemical Society , 2005, DOI: 10.1590/S0103-50532005000400019
Abstract: the biotransformation of digitoxigenin (1) by fusarium ciliatum was investigated. the cardenolide 1 was obtained by the acid hydrolysis of digitoxin and the reaction also afforded two side products, identified as d14-15-digitoxigenin (2) and d8-14-digitoxigenin (3) by spectroscopic analysis. the biotransformation reaction was carried out in a 5 days process and three products were isolated and had their structures elucidated as digoxigenin (4), digoxigenone (5) and digitoxigenone (6). the investigation of the biotransformation kinetics disclosed 6 as the first derivative to be formed, followed by the more polar hydroxylated products 4 and 5, suggesting the involvement of different enzymes in 12b hydroxylation and c-3 oxydation of digitoxigenin (1). the production of 5 and 6 under the employed conditions has never been reported. the biotransformation reaction was also undertaken with digitoxin, but f. ciliatum has been unable to promote its hydroxylation.
Biotransformation of digitoxigenin by Cochliobolus lunatus
Pádua, Rodrigo M.;Oliveira, Alaíde B.;Souza Filho, José D.;Takahashi, Jacqueline A.;Silva, Maurício de Abreu e;Braga, Ferno C.;
Journal of the Brazilian Chemical Society , 2007, DOI: 10.1590/S0103-50532007000700002
Abstract: the biotransformation of digitoxigenin (1) by cochliobolus lunatus was investigated. the biotransformation reaction was carried out in a 4-day process, resulting in the isolation of four products, whose structures were elucidated as 1b-hydroxydigitoxigenin (2), 7b-hydroxydigitoxigenin (3), 8b-hydroxydigitoxigenin (4) and digitoxigenone (5). the production of these derivatives under the employed conditions has never been described so far. this is also the first report on the production of compound 4 by a biotransformation reaction.
Plant-derived antimalarial agents: new leads and efficient phythomedicines. Part I. Alkaloids
Oliveira, Alaíde B.;Dolabela, Maria Fani;Braga, Ferno C.;Jácome, Rose L.R.P.;Varotti, Fernando P.;Póvoa, Marinete M.;
Anais da Academia Brasileira de Ciências , 2009, DOI: 10.1590/S0001-37652009000400011
Abstract: malaria remains one of the most serious world health problem and the major cause of mortality and morbidity in the endemic regions. brazil is among the 30 high-burden countries and most of the cases occur in the legal amazonian region. new chemotherapeutical agents are needed for the treatment of malaria. many plant species are used in traditional medicines of malarious countries and a relatively few number of these have been investigated for evaluation of their antimalarial effect. still lower is the number of those that have had the active natural compounds isolated and the toxicity determined. this area is, then, of great research interest. discovery project of antimalarial natural products from plants traditionally used to treat malaria must include in vitro and in vivo assays as well as bioguided isolation of active compounds. the final products would be antimalarial chemical entities, potential new drugs or templates for new drugs development, and/or standardized antimalarial extracts which are required for pre-clinical and clinical studies when the aim is the development of effective and safe phythomedicines. this review discusses these two approaches, presents briefly the screening methodologies for evaluation of antimalarial activity and focuses the activity of alkaloids belonging to different structural classes as well as its importance as new antimalarial drugs or leads and chemical markers for phytomedicines.
Atividade vasodilatadora in vitro de espécies de Ouratea (Ochnaceae) e de fra??es de Ouratea Semiserrata (Mart.) Engl.
Valadares, Ydia Mariele;Oliveira, Alaíde Braga de;C?rtes, Steyner F.;Lombardi, Júlio Ant?nio;Braga, Ferno Castro;
Revista Brasileira de Ciências Farmacêuticas , 2003, DOI: 10.1590/S1516-93322003000100009
Abstract: ouratea species occur in the cerrado vegetation and some species are popularly used as tonic, astringent and anti-inflammatory. in the present work, we assayed the vasodilator effects of o. castanaefolia, o. spectabilisand o. semiserrata hydroethanolic extracts in aortic rings pre-contracted with phenylephrine. only o. semiserrata stem extract (os) produced significant vasodilatation (63 ± 3 %, n = 6), at the concentration of 100 mg/ml. bioguided fractionation of os afforded a proanthocyanidin-rich fraction that produced 100 ± 5 % vasodilatation (n = 6; concentration of 100 mg/ml). the total proanthocyanidin contents were assayed for os and for the bioactive fractions using a spectroscopic method. higher proanthocyanidin contents implied in increased vasodilator activity (r2 = 0.9760), suggesting that compounds of this class may be regarded as responsible for the activity of o. semiserrata stem extract.
Surfactant Enhanced Chemofiltration of Zinc Traces Previous to Their Determination by Solid Surphase Fluorescence  [PDF]
Mabel Vega, Miriam Augusto, María C. Talío, Liliana P. Fernández
American Journal of Analytical Chemistry (AJAC) , 2011, DOI: 10.4236/ajac.2011.28104
Abstract: Surfactant enhanced chemofiltration on Nylon membranes pre-treated with hexadecyltrimethylammonium bromide (HTAB) and eosin dye (eo) is proposed for zinc traces quantification by solid surphase spectro- fluorimetry (SSF, λexc = 532 nm; λem = 548 nm). Operational variables which have influence on quantitative retention of metal complex have been studied and optimized. At optimal experimental conditions, quantita- tive recovery was reached with a detection limit of 0.662 pg?L–1 and quantification limit of 2.20 pg?L–1. The calibration sensitivity was of 1.22 L?pg–1 for the new methodology with a linear range of 2.20 pg?L–1 to 779 pg?L–1 Zn (II). The tolerance levels of potential interfering ions were studied with good results. Recuperation studies were carried out by standard addition method applied to natural water samples (San Juan, Argentine) without previous treatment. The reproducibility (between-days precision) was also evaluated over 3 days by performing five determinations each day. CV% was 0.37. The performing obtained in sensitivity and selec- tivity thanks to chemofiltration step, converts the proposed methodology in an adequate alternative to con- ventional techniques for Zn (II) traces determination.
Osmotic Stress Effect over Carbohydrate Production in a Native Starin of Scenedesmus sp.  [PDF]
Pilar Bremauntz, Luis C. Fernández-Linares, Rosa O. Ca?izares-Villanueva
Natural Resources (NR) , 2014, DOI: 10.4236/nr.2014.51002
Abstract:

The production of biofuels is currently presented as a possible answer in the search for sustainable alternatives for the total or partial substitution of fossil fuels. One of the most successful biofuels that have been developed is bioethanol. However, bioethanol production has been limited since it relies on the use of sugar cane or cereals. These materials are important sources of food and their demand as both a biofuel and a foodstuff has led to the price increase and may lead to possible shortages. Our group has focused on searching for native microalgae as sources of carbohydrates and bioethanol, with the goal of finding a sustainable source of bioethanol. Currently, twelve different strains which reach growth rates between 0.7 - 1.8 g/L and present carbohydrate production under osmotic shock conditions have been isolated. In this work, we demonstrate the results obtained with the Chlorella sp. [1] strain and the results obtained with the Scenedesmus sp. strain. The Scenedesmus sp. strain showed an increase in the production from 22 to 650 mg/sugar/g of biomass (dry weight), after 24 hours of osmotic shock with 0.1 M NaCl. The osmolytes which were produced after osmotic shock were identified as sucrose and trehalose, both of which are fermentable. These results demonstrate that this strain, through the photosynthetic pathway and osmotic shock, is a potential source of fermentable

Disease Prevalence and Symptoms Caused by Alternaria tenuissima and Pestalotiopsis guepinii on Blueberry in Entre Ríos and Buenos Aires, Argentina  [PDF]
Rocío L. Fernández, Marta C. Rivera, Bruno Varsallona, Eduardo R. Wright
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.619301
Abstract: About 60% of blueberry (Vaccinium corymbosum) plantations in Argentina are located in the provinces of Entre Ríos and Buenos Aires. Alternaria tenuissima and Pestalotiopsis guepinii have been reported as pathogens of blueberry, causing leaf spots and branch cankers. The aims of this research were to estimate the prevalence of these microorganisms on leaves and fruits taken from crops located in Entre Ríos and Buenos Aires, as well as to differentiate leaf symptoms after target inoculations with each pathogen individually and in mixtures. Both fungi were present in blueberry fields from 2010 to 2013. A. tenuissima was the most prevalent pathogen, as most of the symptoms detected in the fields had been caused by this species. As a result of inoculations on cv. O’Neal, injured tissues showed symptoms before undamaged ones. Leaf symptoms caused by A. tenuissima differed from those caused by P. guepinii because of their predominant reddish color and the absence of drop-off of the central part of the lesions. When inoculated in a mixture, incubation period on leaves was intermediate between the registered for individual inoculations. The leaves showed reddishbrown spots typical of A. tenuissima and dark brown spots typical of P. guepinii, both with red margins. Blight, defoliation and canker symptoms caused in each case were undistinguishable.
Page 1 /345303
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.