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URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11800
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Item Activity of essential oil of Lippia triplinervis Gardner (Verbenaceae) on Rhipicephalus microplus (Acari: Ixodidae)(Parasitology Research, 2013-02) Lage, Tiago Coelho de Assis; Montanari, Ricardo Marques; Fernandes, Sergio Antonio; Monteiro, Caio Márcio de Oliveira; Senra, Tatiane de Oliveira Souza; Zeringota, Viviane; Calmon, Fernanda; Matos, Renata da Silva; Daemon, ErikThe objective of this work was to characterize and investigate the acaricidal activity of the essential oil of the aerial parts of Lippia triplinervis at different concentrations on unengorged larvae and engorged females of Rhipicephalus microplus. The essential oil yielded 2.21 % (w/w to dry matter) and was composed mainly of carvacrol (31.9 %), thymol (30.6 %), and p-cymene (12.3 %). Two tests were performed to assess the acaricidal activity: the modified larval packet test, with concentrations of 2.5, 5.0, 10.0, 15.0, and 20.0 mg/mL and the female immersion test, with concentrations of 10.0, 20.0, 30.0, 40.0, and 50.0 mg/mL. There were ten repetitions for each concentration, and for each test, a control group was formed in which the ticks were treated with Tween 80 (20 mg/mL). The experimental groups were kept in a climate-controlled chamber (27 ± 1 °C and RH >80 %). The mortality of the larvae was above 95 % in all the groups tested and reached 100 % as of the 5.0 mg/mL concentration, while the control group exhibited 0 % mortality. In the female immersion test, there was a significant decline (p < 0.05) in the egg mass weight, egg production index, and hatching percentage starting at the concentration of 30.0, 40.0, and 20.0 mg/mL, respectively, and the control percentage at the concentrations of 40.0 and 50.0 mg/mL were above 90 and 95 %. The L. triplinervis oil as thus an alternative source of the monoterpenes thymol, carvacrol, and p-cymene, and its toxicity on R. microplus larvae and females makes it promising possibility for control of this tick.Item Essential oils from pequi fruits from the brazilian Cerrado ecosystem(Food Research International, 2013-11) Geőcze, K. C.; Barbosa, L. C. A.; Fidêncio, P. H.; Silvério, F. O.; Lima, C. F.; Barbosa, M. C. A.; Ismail, Fyaz M. D.The composition of the essential oils of pequi fruits gathered from the Brazilian Cerrado ecosystem in the states of Maranhão (MA), Minas Gerais (MG) and Tocantins (TO) was investigated. The oils were obtained by steam distillation, and each component was speciated using GC-MS. The oil content varied from 0.13% to 1.15%. Interestingly, the major substance found within samples from two of the states was ethyl hexanoate (MA, MG), whereas isopropyl hexanoate and isopentyl-2-methylbutanoate were specific for the samples from TO. Both principal components analysis (PCA) and hierarchical cluster analysis (HCA) were used for exploratory analysis of the oils, and, consequently, the pequi fruits were classified according to their place of origin. The PCA showed that 51.5% of the variance accumulated in the PC1 and PC3, and the group formation obtained using HCA confirmed that the oil composition is influenced by geographic and/or plant genetic factors. Such analyses could assist in the selection of more flavoursome and healthy variants of pequi.Item Extracts from the leaves of Piper piscatorum (Trel. Yunc.) obtained by supercritical extraction of with CO2, employing ethanol and methanol as co-solvents(Industrial Crops and Products, 2013-05) Pimentel, Flávio A.; Cardoso, Maria das G.; Guimarães, Luiz G.L.; Queiroz, Fabiana; Barbosa, Luiz C.A.; Morais, Augusto R.; Nelson, David L.; Andrade, Milene A.; Zacaroni, Lidiany M.; Pimentel, Sônia Maria N.P.The efficiency of the extraction of fresh and dried leaves of Piper piscatorum was evaluated employing supercritical CO2 and co-solvents (10% ethanol and 10% methanol) at 40 °C and 70 °C and a pressure of 400 bar. The extracts were characterized chemically by GC–MS and GC–FID. The major components of the extracts were piperovatine, followed by palmitic acid, pentadecane and pipercallosidine. Drying of the leaves caused modifications in their composition, mainly reducing the concentration of the amides, which have activity as anesthetics. The highest yields of the piperovatine (0.93%, w/w) and pipercallosidine (0.24%, w/w) were obtained from the fresh leaves extracted with CO2 modified with 10% ethanol at 40 °C.Item β-Cyclodextrin-assisted synthesis of Biginelli adducts under solvent-free conditions(Tetrahedron, 2013-09-23) Liberto, Natália Aparecida; Silva, Sarah de Paiva; Fátima, Ângelo de; Fernandes, Sergio AntonioA simple, green and efficient protocol was developed using b -cyclodextrin as a solid catalyst for the solvent-free synthesis of various Biginelli adducts. The advantages of our protocol included the following: (i) a metal-free methodology; (ii) high yields; (iii) simple and efficient work-up procedures; (iv) improved results under solvent-free conditions. b -cyclodextrin-catalyzed the Biginelli reactions for various aldehydes, demonstrating that it is an efficient and eco-friendly catalyst for the preparation of heterocyclic compounds.Item Organocatalysis in the three-component Povarov reaction and investigation by mass spectrometry(Organic & Biomolecular Chemistry, 2013-06-13) Simões, Juliana Baptista; Fátima, Ângelo de; Sabino, Adão Aparecido; Aquino, Francisco José Tôrres de; Silva, Daniel Leite da; Barbosa, Luiz Claudio Almeida; Fernandes, Sergio AntonioA diastereoselective three-component cascade reaction, catalyzed by p-sulfonic acid calix[4]arene, provides a unique method to access diverse julolidine derivatives in high yields. Additionally, the reaction was also monitored by mass spectrometry and the mechanistic pathway uncovered.Item Biochemical responses of Anticarsia gemmatalis (Lepidoptera: Noctuidae) in Soybean cultivars sprayed with the protease Inhibitor Berenil(Journal of Agricultural and Food Chemistry, 2013-08-02) Paixão, Gilson P.; Lourenção, André L.; Silva, Camila R.; Mendonça, Eduardo G.; Silva, Paulo L.; Oliveira, Joel A.; Zanuncio, José C.; Oliveira, Maria Goreti A.The damage caused by Anticarsia gemmatalis motivates this study on the adaptive mechanisms of the insect to soybean. The lipoxygenase pathway produces and releases jasmonic acid, involved in the regulation of the plant defense genes, which encodes protease inhibitor (PI) production. Three soybean cultivars IAC-18, IAC-24, and Foscarin-31 were sprayed with water and berenil, a synthetic inhibitor, at 0.60 and 1.0% (w/v) and then infested with A. gemmatalis larvae. The lipoxygenase (LOX) activity increased in the leaves of Foscarin-31, IAC-18, and IAC-24 by 87, 81, and 78%, respectively, after 24 h of A. gemmatalis damage. IAC-18 revealed the lowest increase in PI when compared to the other cultivars. Protease, amidase, and esterase activities in soybean larvae dropped drastically after berenil application. PIs may be included in the control strategies of A. gemmatalis in soybean by lowering the digestive enzyme activity in the larval midgut, thus affecting insect growth and development.Item Application of hydrophobic extractant in aqueous two-phase systems for selective extraction of cobalt, nickel and cadmium(Journal of Chromatography A, 2013-03-01) Rodrigues, Guilherme Dias; Lemos, Leandro Rodrigues de; Silva, Luis Henrique Mendes da; Silva, Maria C. Hespanhol daThis work developed a new and efficient method of extracting and separating Co(II), Ni(II) and Cd(II) in aqueous two-phase systems (ATPS) composed of triblock copolymer (L64) + Na2C4H4O6 + water and L64 + Li2SO4 + water using the hydrophobic extractant 1-nitroso-2-naphtol, which complexes the metal ions and partitions in the triblock copolymer micelles in the ATPS top phase. Metal extraction from the salt-rich phase to the copolymer – rich phase is strongly affected by the fine-tuning of the following parameters: amount of added extractant, type of electrolyte, pH, and tie-line length. Excellent separation factors (Si,j) between the metals were obtained at pH = 3.00 (SCo,Cd = 1550 and SNi,Cd = 16,700) and pH = 1.00 (SCo,Ni = 826). In the interference study, Co(II) was selectivity extracted in the top phase in the presence of Ni(II) and Cd(II) in a concentration of up to 20 times the cobalt level in the system.Item Synthetic analogues of the natural compound cryphonectric acid interfere with photosynthetic machinery through two different mechanisms(Journal of Agricultural and Food Chemistry, 2013-05-17) Teixeira, Róbson Ricardo; Pereira, Wagner Luiz; Tomaz, Deborah Campos; Oliveira, Fabrício Marques de; Giberti, Samuele; Forlani, GiuseppeA series of isobenzofuran-1(3H)-ones (phthalides), analogues of the naturally occurring phytotoxin cryphonectric acid, were designed, synthesized, and fully characterized by NMR, IR, and MS analyses. Their synthesis was achieved via condensation, aromatization, and acetylation reactions. The measurement of the electron transport chain in spinach chloroplasts showed that several derivatives are capable of interfering with the photosynthetic apparatus. Few of them were found to inhibit the basal rate, but a significant inhibition was brought about only at concentrations exceeding 50 μM. Some other analogues acted as uncouplers or energy transfer inhibitors, with a remarkably higher effectiveness. Isobenzofuranone addition to the culture medium inhibited the growth of the cyanobacterium Synechococcus elongatus, with patterns consistent with the effects measured in vitro upon isolated chloroplasts. The most active derivatives, being able to completely suppress algal growth at 20 μM, may represent structures to be exploited for the design of new active ingredients for weed control.Item Theoretical and experimental study of inclusion complexes formed by isoniazid and modified β-Cyclodextrins: 1H NMR structural determination and antibacterial activity evaluation(The Journal of Physical Chemistry B, 2013-12-09) Teixeira, Milena G.; Assis, João V. de; Soares, Cássia G. P.; Venâncio, Mateus F.; Lopes, Juliana F.; Nascimento Jr, Clebio S.; Anconi, Cleber P. A.; Carvalho, Guilherme S. L.; Lourenço, Cristina S.; Almeida, Mauro V. de; Fernandes, Sergio A.; Almeida, Wagner B. deMe-β-cyclodextrin (Me-βCD) and HP-β-cyclodextrin (HP-βCD) inclusion complexes with isoniazid (INH) were prepared with the aim of modulating the physicochemical and biopharmaceutical properties of the guest molecule, a well-known antibuberculosis drug. The architectures of the complexes were initially proposed according to NMR data Job plot and ROESY followed by density functional theory (DFT) calculations of (1)H NMR spectra using the PBE1PBE functional and 6-31G(d,p) basis set, including the water solvent effect with the polarizable continuum model (PCM), for various inclusion modes, providing support for the experimental proposal. An analysis of the (1)H NMR chemical shift values for the isoniazid (H6',8' and H5',9') and cyclodextrins (H3,5) C(1)H hydrogens, which are known to be very adequately described by the DFT methodology, revealed them to be extremely useful, promptly confirming the inclusion complex formation. An included mode which describes Me-βCD partially enclosing the hydrazide group of the INH is predicted as the most favorable supramolecular structure that can be used to explain the physicochemical properties of the encapsulated drug. Antibacterial activity was also evaluated, and the results indicated the inclusion complexes are a potential strategy for tuberculosis treatment.Item Exploratory and discriminative studies of commercial processed Brazilian coffees with different degrees of roasting and decaffeinated(Brazilian Journal of Food Technology, 2013-09) Teófilo, Reinaldo Francisco; Ribeiro, Juliano Souza; Salva, Terezinha de Jesus Garcia; Augusto, Fabio; Ferreira, Marcia Miguel CastroThe fingerprints of the volatile compounds of 21 commercial Brazilian coffee samples submitted to different industrial processing i.e. decaffeinated or different roasting degrees (traditional and dark) were studied. The volatiles were collected by headspace solid phase microextraction (HS-SPME) and analyzed by GC-FID and GC-MS. The chromatographic data matrices (fingerprints) obtained were explored by the principal component analysis (PCA) and partial least squares – discriminative analysis (PLS-DA). Initially the chromatographic profiles were aligned by the algorithm correlation optimized warping (COW). The PCA showed the discrimination of the decaffeinated coffees from the others with both the SPME fibres used. This separation probably occurred due to the loss of some volatile precursors during the decaffeination process, such as sucrose. For both the fibres tested, PDMS/DVB and CX / PDMS SPME, the PLS-DA models correctly classified 100% of the samples according to their roasting degree: (medium and dark), the main differences being the concentrations of some of the volatile compounds such as 2-methyl furan, 2-methylbutanal, 2,3-pentanedione, pyrazine, 2-carboxyaldehyde pyrrole, furfural and 2-furanmethanol.