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151.
152.
Claudia Rebeca Rivera-Yaez Porfirio Alonso Ruiz-Hurtado Julia Reyes-Reali María Isabel Mendoza-Ramos María Elena Vargas-Díaz Karla Mariela Hernndez-Snchez Glustein Pozo-Molina Claudia Fabiola Mndez-Catal Gina Stella García-Romo Alexander Pedroza-Gonzlez Adolfo Ren Mndez-Cruz Oscar Nieto-Yaez Nelly Rivera-Yaez 《Molecules (Basel, Switzerland)》2022,27(17)
Infections caused by micro-organisms of the genus Candida are becoming a growing health problem worldwide. These fungi are opportunistic commensals that can produce infections—clinically known as candidiasis—in immunocompromised individuals. The indiscriminate use of different anti-fungal treatments has triggered the resistance of Candida species to currently used therapies. In this sense, propolis has been shown to have potent antimicrobial properties and thus can be used as an approach for the inhibition of Candida species. Therefore, this work aims to evaluate the anti-Candida effects of a propolis extract obtained from the north of Mexico on clinical isolates of Candida species. Candida species were specifically identified from oral lesions, and both the qualitative and quantitative anti-Candida effects of the Mexican propolis were evaluated, as well as its inhibitory effect on C. albicans isolate’s germ tube growth and chemical composition. Three Candida species were identified, and our results indicated that the inhibition halos of the propolis ranged from 7.6 to 21.43 mm, while that of the MFC and FC50 ranged from 0.312 to 1.25 and 0.014 to 0.244 mg/mL, respectively. Moreover, the propolis was found to inhibit germ tube formation (IC50 ranging from 0.030 to 1.291 mg/mL). Chemical composition analysis indicated the presence of flavonoids, including pinocembrin, baicalein, pinobanksin chalcone, rhamnetin, and biochanin A, in the Mexican propolis extract. In summary, our work shows that Mexican propolis presents significant anti-Candida effects related to its chemical composition, and also inhibits germ tube growth. Other Candida species virulence factors should be investigated in future research in order to determine the mechanisms associated with antifungal effects against them. 相似文献
153.
Augusto Rivera Diego Quiroga Leonardo Jiménez-Cruz Karla Fejfarová Michal Dušek 《Tetrahedron letters》2012,53(3):345-348
New enantiomerically pure macrocyclic aminals (2R,7R)- and (2S,7S)-1,8,10,12-tetraazatetracyclo[8.3.1.1.8,1202,7]pentadecane (4a and 4b) were obtained by a three component reaction between their respective pure enantiomer of trans-1,2-diaminocyclohexane, ammonia, and formaldehyde. Additionally, the X-ray structure of the racemic compound 4 and the specific rotations of the racemic and optically pure compounds were determined. To further understand the synthetic utilities of enantiomers 4a and 4b, Mannich-type reactions with 1H-benzotriazole were performed, affording (3aR,7aR)- and (3aS,7aS)-1,1′-{[2,3,3a,4,5,6,7,7a-octahydro-1H-1,3-benzimidazole-1,3-diyl]bis(methylene)}bis-1H-benzotriazole (9 and 10) and allowing for new possibilities related to the preparation of chiral ligands for asymmetric catalysis. 相似文献
154.
The synthesis of a stable ketene aminal phosphate (α-phosphoryloxy enecarbamate) derived from N,N-diprotected acetamide, bearing two different removable protecting groups, is disclosed. This synthetic intermediate underwent successful palladium-catalyzed cross-coupling reactions to afford functionalized enynes and dienes. 相似文献
155.
Tersago K Mandado M Van Alsenoy C Bagryanskaya IY Kovalev MK Makarov AY Gatilov YV Shakirov MM Zibarev AV Blockhuys F 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(15):4544-4551
The existence of the orbital interaction presented in the literature as being the cause for the stabilisation of the Z,Z configuration of Ph-S-N=S=N-S-Ph (1) and its derivatives in the crystal phase, has been investigated. The results of theoretical calculations at the DFT/B3LYP/6-311+G* level of theory suggest that such a stabilising interaction might not exist or be extremely weak and that packing forces must be the main cause of the observed Z,Z configuration in the solid. To reach this conclusion structural and energetic parameters were combined to study the bonding in these -S-N=S=N-S- systems. For the analogous Ph-Se-N=S=N-Se-Ph (2) in particular the isomeric equilibrium in solution found in the variable-temperature 77Se NMR spectrum indicates that, in the gas phase or in solution, the observed Z,Z configuration is not stabilised to a greater extent than the Z,E configuration. 相似文献
156.
Cristina Fontes Diniz Karla Balzuweit Nelcy Della Santina Mohallem 《Journal of nanoparticle research》2007,9(2):293-300
Alumina nanotube was synthesized by hydrolysis of aluminum isopropoxide followed by gelation and drying under hypercritical
condition. The influence of temperature on the structural, textural, and morphological properties of the material was studied
by powder X-ray diffraction, infrared spectroscopy, nitrogen adsorption, thermal analysis, scanning and transmission electronic
microscopy. The as-prepared alumina (300°C) was formed by boehmite crystallites. Its structure collapsed after heating (500–1200
°C) yielding γ, δ and θ alumina nanophases. The aerogel surface area changed from 254 to 99 m2 g−1 in this heating range. The formation of alumina nanotubes was verified by transmission microscopy analysis at the heating
range. 相似文献
157.
[structures: see text] Dithieno[3,2-b:2',3'-d]pyrrole-based terthiophene (2a-c) and quaterthiophene (3a-c) analogues have been prepared from dithieno[3,2-b:2',3'-d]pyrrole (1) via Stille coupling utilizing a one-pot method. In comparison to the parent oligothiophenes (T(n), where n = 2-4), the resulting dithieno[3,2-b:2',3'-d]pyrrole-based systems exhibit enhanced fluorescence efficiencies in solution (up to 53%). These new oligomeric systems also allow the incorporation of solubilizing side chains without the negative steric interactions that typically reduce backbone planarity. 相似文献
158.
NH4[PO2F(NH2)] has been prepared by the reaction of a betaine py·PO2F with excess ammonia in acetonitrile solution, while the ammonolysis of DMAP·PO2F with a stoichiometric amount of NH3 yields [DMAPH][PO2F(NH2)]. The crystal structure of the latter was determined by single‐crystal X‐ray diffraction, which revealed that the anions [PO2F(NH2)]— are linked to infinite chains by double N—H···O bridges. Additional strong N—H···O bridging bonds connect each anion with its [DMAPH]+ counterion. The formation of a new betaine NH3·PO2F in the solution of py·PO2F in liquid ammonia was proved by 31P NMR spectroscopy and by identification of its hydrolysis products. 相似文献
159.
Mardones C Hitschfeld A Contreras A Lepe K Gutiérrez L von Baer D 《Journal of chromatography. A》2005,1085(2):285-292
Two capillary zone electrophoretic (CZE) methods for determination of shikimic acid in Chilean red wine were developed and compared with a HPLC method. Both electrophoretic methods were carried out by using a reversed electroosmotic flow induced by trimethyl(tetradecyl)ammoniumbromide (TTAB) with indirect detection at 260 nm using p-aminobenzoic acid as a UV-absorbing co-ion or by direct detection at 213 nm. In both cases, the separation was carried out in a 50 microm I.D. uncoated capillary with an effective length of 48 cm, a negative power supply of 30 kV, using a buffer based on bis[2-hydroxyethyl]imino-tris[hydroxymethyl]methane (Bis-Tris), pH 7.0 or 7.5 and hydrodynamic injection. The chromatographic separations were carried out on a C-18 reversed phase column followed by a sulfonyl-styrene-divinylbenzene (S-DVB) ion exclusion column at 70 degrees C with H2SO4 0.02 M as isocratic mobile phase and a flow rate of 0.5 mL min(-1). The three methods allowed the quantification of shikimic acid with quantification limits between 1.0 and 12.0 mg L(-1) and precision between 7.3 and 10.1%, however, only the concentrations obtained by CZE with direct detection were statistically similar to those of HPLC. This parameter was evaluated as analytical tool to verify varietal authenticity of red wines. In all cases, the Cabernet Sauvignon wines presented higher concentrations of shikimic acid, compared with Merlot or Carmenère wines. 相似文献
160.
Maria F. B. Morais-Braga Teógenes M. Souza Karla K. A. Santos Gláucia M. M. Guedes Jacqueline C. Andrade Saulo R. Tintino 《Natural product research》2016,30(16):1851-1853
The aim of this work was to evaluate the interactions between gentamicin and the ethanol extract of the fern Lygodium venustum SW (EELV). The ethanol extract of L. venustum was obtained, the phytocompounds were identified and the EELV was assayed by the checkerboard method with gentamicin against two bacterial strains multiresistant to antibiotics. The antibiotic activity of gentamicin, when associated with the extract, was enhanced in an additive manner against both strains. The results indicated that L. venustum can be a source of secondary metabolites to be used in association with antibiotics as aminoglycosides in the antibiotic chemotherapy against resistant bacteria. 相似文献