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URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11800

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Agora exibindo 1 - 4 de 4
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    Determinação da relação siringila/guaiacila da lignina em madeiras de eucalipto por pirólise acoplada à cromatografia gasosa e espectrometria de massas ( PI - CG/ EM)
    (Química Nova, 2008) Barbosa, Luiz C. A.; Maltha, Célia R. A.; Silva, Vanessa Lopes; Colodette, Jorge Luiz
    The use of analytical pyrolysis combined with gas chromatography/mass spectrometry (Py-GC/MS) to determine the syringyl/guaiacyl ratio (S/G) in lignins from Eucalyptus spp woods was investigated. Sample of E. grandis and "E. urograndis" wood, with and without extractives, were subjected to pyrolysis from 300 ºC to 600 ºC. The products that results from pyrolysis were identified by mass spectrometry and the S/G ratio was determined based on the areas of the peaks corresponding to the guaiacyl and syringyl derivatives. The best S/G estimation is achieved when pyrolysis is carried out at 550 ºC. Extractives and carbohydrate present in the woods do not interfere with the results.
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    Atividade antiinflamatória de carboidrato produzido por fermentação aquosa de grãos de quefir
    (Química Nova, 2008) Moreira, Maria E. C.; Santos, Marcelo H.; Pereira, Ivan O.; Ferraz, Vany; Barbosa, Luiz C. A.; Schneedorf, José M.
    Kefir, a symbiont microorganism suspension, presents benefic effects to health. Some kefir grains were cultivated in brown sugar, allowing to isolate a substance named CSQ. This was evaluated on a biologic essay of mouse foot edema, presenting an inhibitory activity of 30+4 % against carrageenan after the stimulus. It was observed that a cultivation mean containing sucrose, and not the milky mean, lead to the production of different sugar polymeric chains of kefir. The results in vivo suggest that the CSQ exerted an anti-inflammatory activity.
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    Síntese e avaliação da atividade fitotóxica de derivados da α-Santonina
    (Química Nova, 2009) Alvarenga, Elson S.; Barbosa, Luiz C. A.; Saliba, William A.; Arantes, Francisco F. P.; Demuner, Antônio J.; Silva, Antônio A.
    Mixtures of α-Santonin and various solvents were irradiated by either high or low pressure mercury lamps. The photochemical reactions afforded lumisantonin (11) (76% in acetonitrile), (3S,3aS,9bS)-3,6,6-trimethyl-3,3a,4,5-tetrahydronafto[1,2-b]furan-2,7(6H,9bH)dione (12) (100% in acetonitrile), 10α-acetoxy-3-oxo-1,7αH,6,11βH-guaia-4-en-6,12-olide (8) (26% in acetic acid), 10α-hydroxy-3-oxo-1,7αH,6,11βH-guaia-4-en-6,12-olide (10) (32%) and (E)-3-((3S,3aS,7aS)-3-methyl-2-oxo-6-(propan-2-ylidene)hexahydrobenzofuran-7-(7aH)-ylidene)propanoic acid (9) (44%) (in water/ acetic acid 1:1, v/v). Lactone 12 was also prepared by irradiation of lumisantonin in diethyl ether. Lactones 8 and 10 were converted, respectively, into the 10α-acetoxy-3β-hydroxy-1,7αH,6,11βH-guaia-4-en-6,12-olide (13) (87%) and 3β,10α-dihydroxy-1,7αH,6,11βH-guaia-4-en-6,12-olide (14) (75%) by sodium borohydride reduction. The effects of the compounds on the development of radicle of Sorghum bicolor and Cucumis sativus were evaluated.
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    Antioxidant activity of Maytenus imbricata Mart., Celastraceae
    (Revista Brasileira de Farmacognosia, 2008-11-29) Barbosa, Luiz C. A.; Ribeiro, Sonia M. R.; Queiroz, José H.; Oliveira, Márcio L. R.; Silva, Grácia D. F.; Silva, Silvia R. S.; Duarte, Lucienir P.; Vieira Filho, Sidney A.
    The free radical scavenging activity (FRS) using 2,2-diphenyl-1-picrylhydrazyl (DPPH), the reducer power and the total phenolic concentration of extracts and compounds isolated from leaves, branches and roots of Maytenus imbricata Mart. (Celastraceae) were evaluated. Some extracts, a mixture of phenolic compounds (MPC) and epicatechin showed higher RP and FRS (DPPH) activities in comparison with the standard butylhydroxyanisole (BHA) and galic acid (GA) used in assays. The ethyl acetate extract from leaves showed higher total phenolic content and also higher RP and FRS (DPPH) than the other extracts. These facts indicate that there are some relations between phenolic concentration in the extract and the antioxidant activity and the reducer power. The solvent used in the extraction process influences the chemical composition of the extracts and consequently its antioxidant and reducer power activities.