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| Registros recuperados: 91 | |
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| Devia,Cristina M.; Pappano,Nora B.; Debattista,Nora B.. |
| The bacteriostatic activity of 2,4,2-trihydroxychalcone; 2,4,3-trihydroxychalcone and 2,4,4-trihydroxychalcone, prepared by condensation of 2,4-dihydroxyacetophenone and benzaldehyde substituted, against Staphylococcus aureus ATCC 25923 was assayed by agar plate method. The three compounds presented important inhibition halos. In order to elucidate structure-activity relationships, the minimal inhibitory concentrations against S. aureus were determined by the broth dilution method and the results obtained were compared to that of 2',4'-dihydroxychalcone. The sequence observed was: MIC 2,4,3-(OH)3 > MIC 2,4-(OH)2 > MIC 2,4,4-(OH)3 > > MIC 2,4,2-(OH)3. These results showed that the introduction of an electron... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bacteriostatic activity; Structure-activity relationship; Flavonoids; Trihydroxylated chalcones. |
| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37141998000400014 |
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| Di Pietro,A.; Dayan,G.; Conseil,G.; Steinfels,E.; Krell,T.; Trompier,D.; Baubichon-Cortay,H.; Jault,J.-M.. |
| Resistance to chemotherapy in cancer cells is mainly mediated by overexpression of P-glycoprotein (Pgp), a plasma membrane ATP-binding cassette (ABC) transporter which extrudes cytotoxic drugs at the expense of ATP hydrolysis. Pgp consists of two homologous halves each containing a transmembrane domain and a cytosolic nucleotide-binding domain (NBD) which contains two consensus Walker motifs, A and B, involved in ATP binding and hydrolysis. The protein also contains an S signature characteristic of ABC transporters. The molecular mechanism of Pgp-mediated drug transport is not known. Since the transporter has an extraordinarily broad substrate specificity, its cellular function has been described as a "hydrophobic vacuum cleaner". The limited knowledge... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: P-glycoprotein (Pgp); Multidrug resistance; Anticancer chemotherapy; ATP; Steroids; Flavonoids. |
| Ano: 1999 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1999000800001 |
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| Dajas,F.; Rivera-Megret,F.; Blasina,F.; Arredondo,F.; Abin-Carriquiry,J.A.; Costa,G.; Echeverry,C.; Lafon,L.; Heizen,H.; Ferreira,M.; Morquio,A.. |
| The high morbidity, high socioeconomic costs and lack of specific treatments are key factors that define the relevance of brain pathology for human health and the importance of research on neuronal protective agents. Epidemiological studies have shown beneficial effects of flavonoids on arteriosclerosis-related pathology in general and neurodegeneration in particular. Flavonoids can protect the brain by their ability to modulate intracellular signals promoting cellular survival. Quercetin and structurally related flavonoids (myricetin, fisetin, luteolin) showed a marked cytoprotective capacity in in vitro experimental conditions in models of predominantly apoptotic death such as that induced by medium concentrations (200 µM) of H2O2 added to PC12 cells in... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Flavonoids; Quercetin; Focal ischemia; Neuroprotection. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003001200002 |
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| Branco,Alexsandro; Pinto,Angelo C.; Braz Filho,Raimundo. |
| From the hexane and ethyl acetate extracts obtained from stems, roots and leaf sheaths of Vellozia graminifolia, a mixture of linear hydrocarbons, a mixture of pentacyclic triterpenes, five monoisoprenylated flavonoids and one labdane diterpene, (-)-ent-3beta-hydroxy-8(17)-labden-15-oic acid, were isolated. The linear hydrocarbons and minor triterpenes were identified in their corresponding mixtures by High Resolution Gas Chromatography (HRGC) and HRGC coupled to mass spectrometry. The major pentacyclic triterpenes and the diterpene were characterized by spectral data, including 2D NMR experiments, and chemical transformations. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Vellozia graminifolia; Velloziaceae; Triterpenes; Diterpene; Flavonoids. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652004000300005 |
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| Magalhães,Aderbal F.; Tozzi,Ana M.G.A.; Magalhães,Eva G.; Blanco,Ivani S.; Soriano,Maria-Del-Pilar C.. |
| The light petroleum extract from the roots of Lonchocarpus muehlbergianus Hassl contained nine flavonoids, including six new ones. These are 2,4-cis-2,4,5,8-tetramethoxy-(2´´,3´´:6,7)-furanoflavan; 2,4-cis-4-hydroxy-2,5,8-trimethoxy-(2´´,3´´:6,7)-furanoflavan; 2,4-cis-2-prenyloxy-4,5,8-trimethoxy-(2´´,3´´:6,7)-fu-ranoflavan; 2,4-cis-2-prenyloxy-4-hydroxy-5,8-dimethoxy-(2´´,3´´:6,7)-furanoflavan; 2',5',6'-trimethoxy-9-(1,1-dimethylallyoxy)-[2´´,3´´:3´,4´]-furanochalcone; 5,6-dimethoxy-(2´´,3´´:7,8)-furanoflavone, identi-fied by analysis of their spectral data (UV, IR, ¹H and 13C NMR, 2D-NMR, NOE and MS). The natural occurrence of 2,4-dioxygenated flavan derivatives is being reported for the first time. Quantitative analysis of the petrol extract, by using... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Lonchocarpus muehlbergianus; Leguminosae; Flavonoids; Flavans. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652004000400004 |
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| Luz,P.L. da; Coimbra,S.R.. |
| Atherosclerosis is a chronic inflammatory disease which may cause obstructions of the coronary, cerebral and peripheral arteries. It is typically multifactorial, most often dependent on risk factors such as hypercholesterolemia, diabetes, smoking, hypertension, sedentarism, and obesity. It is the single main cause of death in most developed countries due to myocardial infarction, angina, sudden death, and heart failure. Several epidemiological studies suggest that moderate alcohol intake, especially red wine, decrease cardiac mortality due to atherosclerosis. The alcohol effect is described by a J curve, suggesting that moderate drinkers may benefit while abstainers and heavy drinkers are at higher risk. Experimental studies indicate that most beneficial... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coronary disease; Beverages; Drinks and cardiac protection; Flavonoids; Wine and grape juice. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004000900001 |
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| Sanches,Neviton Rogério; Garcia Cortez,Diógenes Aparício; Schiavini,Michelle Simone; Nakamura,Celso Vataru; Dias Filho,Benedito Prado. |
| The present study was designated to evaluate the antibacterial activities of aqueous and ethanol:water extracts from leaves, roots and stem bark of Psidium guajava L. The antibacterial activities of the extracts against bacteria were tested by using both microdilution assay. The aqueous extracts of P. guajava leaves, roots and stem bark were active against the gram-positive bacteria Staphylococcus aureus (MICs=500, 125 and 250 µg/ml, respectively) and Bacillus subtilis (MICs=500 µg/ml), and virtually inactive against the gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa (MICs >1000 µg/ml). The ethanol:water extracts showed higher antimicrobial activity as compared to aqueous extracts. Based on this finding, the ethanol:water extract of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Psidium guajava; Antibacterial activities; Flavonoids; Alpha- and beta-amyrin; Beta-sitosterol. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132005000300014 |
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| Coimbra,S.R.; Lage,S.H.; Brandizzi,L.; Yoshida,V.; da Luz,P.L.. |
| Although red wine (RW) reduces cardiovascular risk, the mechanisms underlying the effect have not been identified. Correction of endothelial dysfunction by RW flavonoids could be one mechanism. We measured brachial artery reactivity by high-resolution ultrasonography, plasma lipids, glucose, adhesion molecules (ICAM-1 and VCAM), and platelet function in 16 hypercholesterolemic individuals (8 men and 8 women; mean age 51.6 ± 8.1 years) without other risk factors. Twenty-four normal subjects were used as controls for vascular reactivity. Subjects randomly received RW, 250 ml/day, or purple grape juice (GJ), 500 ml/day, for 14 days with an equal wash-out period. At baseline, all 16 subjects were hypercholesterolemic (mean LDL = 181.0 ± 28.7 mg/dl) but HDL,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Atherosclerosis; Endothelial function; Flavonoids; Alcohol; Red wine and grape juice; Brachial artery dilation. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000900008 |
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| Pak,Adriana; Gonçalez,Edlayne; Felicio,Joana D'arc; Pinto,Marina Mori; Rossi,Maria Helena; Simoni,Isabela Cristina; Lopes,Márcia Nasser. |
| Polymnia sonchifolia, commonly known as ";yacon";, was originally cultivated at Andes moutains in South America. Recently, the specie attracted worldwide attention because of its wide range of uses, for example in the control of diabetes melitus, besides the antifungal and pesticidal compounds were found in the leaves. This study describes the identification of two flavonoids: 3', 5, 7 trihydroxy-3, 4'-dimethoxyflavone (compound 1) and 3', 4', 5- trihydroxy-7-methoxy flavanone (compound 2) and two sesquiterpenes lactones: enhydrin (compound 3) and a mixture of enhydrin and uvedalin (compound 4) isolated from Polymnia sonchifolia leaves and their effects on the aflatoxin production by Aspergillus flavus. The identification of the compounds were achieved by... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Polymnia sonchifolia; Flavonoids; Melampolides; Aflatoxin; Aspergillus flavus. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822006000200018 |
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| Magalhães,Aderbal F.; Tozzi,Ana Maria G.A.; Magalhães,Eva G.; Sannomiya,Miriam; Soriano,Maria del Pilar C.; Perez,Mary A.F.. |
| The analysis of root extracts from Lonchocarpus montanus A.M.G. Azevedo resulted in the isolation of twenty three compounds chiefly flavonoids of which five (four flavonoids and one benzophenone) are described for the first time. The molecular structures of the new compounds (1-5) were determined through spectral analysis (UV, IR, MS and NMR) as being: 2'-hydroxy-8-(<FONT FACE=Symbol>a,a</FONT>-dimethylallyl)-2", 2"-dimethylpyrano-(5",6":3',4')-dibenzoylmethane (1), 2'-methoxy-8-(<FONT FACE=Symbol>a, a</FONT>-dimethylallyl)-2", 2"-dimethylpyrano-(5",6":3',4')-dibenzoylmethane (2), 4'-methoxy-2",2"-dimethylpyrano-(5",6":8,7)-flavone (3), 2"-(1-hydroxy-1-methylethyl)-furano-(4",5":8,7)-flavone (4) and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Lonchocarpus montanus A.M.G. Azevedo; Leguminosae; Dibenzoylmethanes; Flavonoids; Flavones; Benzophenone; Bioautography; Artemia salina lethality. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652007000300001 |
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| Peña,JEM; Vieira,SL; López,J; Reis,RN; Barros,R; Furtado,FVF; Silva,PX. |
| The aim of this study was to evaluate the effects of increasing doses of ascorbic acid (AA) and citric flavonoids (quercetin and rutin) on the performance and meat quality characteristics of broilers submitted to cyclic heat stress. Four-hundred one-day-old female Ross 308 were housed in 40 battery cages a in temperature controlled room. Treatments consisted of 0, 250, 500, and 1000 g/ton on of AA + citric flavonoids. Birds were fed ad libitum until 32 day of age. Beginning on day 14 post-hatch until the end of the experiment, in order to simulate cyclic heat stress, the temperature inside the room was increased to 32°C for 5 hours, and decreased until reaching the comfort temperature corresponding to the age of the animals. Birds were slaughtered at 33... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ascorbic acid; Broiler; Heat stress; Flavonoids. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2008000200008 |
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| Scervino,José Martín; Ponce,María Alejandra; Delia Monica,Ivana; Vierheilig,Horst; Ocampo,Juan Antonio; Godeas,Alicia. |
| We tested the effects of the flavonoid 3-methoxi-5,6,7,8-hydroxy-4'hydroxy flavone (NMHTV) isolated from shoots of non arbuscular mycorrhizal (AM) inoculated clover, and of the flavonoids 5,6,7,8-hydroxy-3-methoxy flavone (MH-1); 5,6,7,8-hydroxy-4'-hydroxy flavone (MH-2); and 5,7-hydroxy-3,4'-methoxy flavone (MH-3); isolated from AM clover {Trifolium repens) shoots, on spore germination, hyphal length, hyphal branches and the number of cluster of auxiliary cells or the number of secondary spores (Presymbiotic stage) and on the number of entry points and the percentage of AM colonized root of tomato (Lycopersicum esculentum) by the AM fungi Gigaspora rosea, Giaspora margarita, Glomus mosseae and Glomus intraradices (Symbiotic stage). Non significant effects... |
| Tipo: Journal article |
Palavras-chave: Arbuscular mycorrhizas; Flavonoids; Signal molecules; Symbiosis. |
| Ano: 2009 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-27912009000200002 |
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| Silva,Tania M.S.; Camara,Celso A.; Lins,Antonio C.S.; Agra,Maria de Fátima; Silva,Eva M.S.; Reis,Igor T.; Freitas,Breno M.. |
| Stingless bees in Brazil are indigenous and found all over the country. Bee pollen is used for its nutritional value in the human diet. It is made up of natural flower pollen mixed with nectar and bee secretions. In order to evaluate the chemical composition, free radical scavenging activity, and botanical origin, sample of pollen loads from stingless bee, Melipona rufiventris (Uruçu amarela) was studied. The EtOAc extract of pollen of Melipona rufiventris yielded the following compounds: p-hydroxycinnamic acid, dihydroquercetin, isorhamnetin, isorhamnetin3-O-(6"-O-E-p-coumaroyl)-β-D-glucopyranoside, luteolin, and quercetin. This is the first report of the isolation of isorhamnetin3-O-(6"O-E-p-coumaroyl)β-D-glucopyranoside from pollen. The free... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Antioxidant activity; Bee pollen; Flavonoids; Melipona rufiventris; Uruçu amarela. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652009000200003 |
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| Registros recuperados: 91 | |
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