Extracts of different polarity of Daphne laureola L. as valuable source of antioxidant and neuroprotective compounds

In this study, Daphne laureola L., an European-Mediterranean species, was investigated for its antioxidant properties using different in vitro bioassays, namely 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), Ferric Reducing Activity Power (FRAP), and β-carotene bleaching assays. The acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity using the Ellman’s method was also examined. The aerial parts of D. laureola were subjected to exhaustive and subsequent macerations with solvents at different polarity, such as methanol, dichloromethane, and n-hexane. Dichloromethane extract was the most promising in DPPH and FRAP tests with IC50 values of 32.2 μg/mL and 71.5 μM Fe(II)/g, respectively. Methanol extract showed the most promising inhibition of lipid peroxidation evaluated by β-carotene bleaching test with an IC50 value of 6.6 μg/mL after 30 min of incubation. This extract was the most active against AChE (IC50 value of 56.9 μg/mL). An interesting result was obtained against BChE by the n-hexane extract, with an IC50 value of 49.7 μg/mL. In conclusion, the results suggest that D. laureola may provide a substantial source of phytochemicals, which act as natural antioxidants and acetylcholinesterase inhibitors, and may be beneficial in the treatment of Alzheimer disease

The photophysics of nitrocarbazoles studied by using spectroscopic, photoacoustic and luminescence techniques

The photophysical behaviour of 1-nitrocarbazol and 3-nitrocarbazol in different organic solvents has been studied by using spectroscopic, luminescence and photoacoustic techniques. Absorption spectra and triplet state transient spectra were recorded and formation quantum yields and lifetimes determined. Phosphorescence emission at 77 K and laser induced luminescence in acetonitrile solution at 298 K for the nitrocarbazoles were studied. Results are discussed in terms of the optimized structure of 1-nitrocarbazole and 3-nitrocarbazole and compared with that of carbazole. The nitro group attached to the carbazole moiety induces important changes in the photophysical behavior of those compounds

The photophysics of nitrocarbazoles studied by using spectroscopic, photoacoustic and luminescence techniques

The photophysical behaviour of 1-nitrocarbazol and 3-nitrocarbazol in different organic solvents has been studied by using spectroscopic, luminescence and photoacoustic techniques. Absorption spectra and triplet state transient spectra were recorded and formation quantum yields and lifetimes determined. Phosphorescence emission at 77 K and laser induced luminescence in acetonitrile solution at 298 K for the nitrocarbazoles were studied. Results are discussed in terms of the optimized structure of 1 -nitrocarbazole and 3-nitrocarbazole and compared with that of carbazole. The nitro group attached to the carbazole moiety induces important changes in the photophysical behavior of those compounds.Facultad de Ciencias Exacta

The photophysics of nitrocarbazoles studied by using spectroscopic, photoacoustic and luminescence techniques

The photophysical behaviour of 1-nitrocarbazol and 3-nitrocarbazol in different organic solvents has been studied by using spectroscopic, luminescence and photoacoustic techniques. Absorption spectra and triplet state transient spectra were recorded and formation quantum yields and lifetimes determined. Phosphorescence emission at 77 K and laser induced luminescence in acetonitrile solution at 298 K for the nitrocarbazoles were studied. Results are discussed in terms of the optimized structure of 1 -nitrocarbazole and 3-nitrocarbazole and compared with that of carbazole. The nitro group attached to the carbazole moiety induces important changes in the photophysical behavior of those compounds.Facultad de Ciencias Exacta

Synthesis, Characterization and Electrocatalytic Activity of Bi- and Tri-metallic Pt-Based Anode Catalysts for Direct Ethanol Fuel Cells

Three Pt-based anode catalysts supported on Vulcan XC-72R (VC) were prepared by using a modified polyol process. These materials were characterized and tested by X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF) and Transmission Electron Microscopy (TEM). XRD and TEM analysis indicated that especially the ternary anode catalysts consisted of uniform nanosized particles with sharp distribution. The Pt lattice parameter was smaller, in the ternary PtSnIr catalyst whereas it increased with the addition of Sn and Rh, in the corresponding binary and ternary catalysts. Cyclic voltammetry (CV) measurements showed that Sn, Ir and Rh may act as promoter of Pt enhancing ethanol electro-oxidation activity. It was found that the direct ethanol fuel cell (DEFC) performances were significantly improved with these modified anode catalysts. This effect on the DEFC performance is attributed to the so-called bi-tri-functional mechanism and to the electronic interaction between Pt and additives. The performance increased significantly with the temperature. However, it was also possible to observe some decay with time for all catalysts due to the formation of surface poisons, probably consisting in CO-like species. At 60 °C, the PtSnIr catalyst showed the best performance, as a result of a proper morphology and promoting effectFil: D'Urso, C.. Centro Nazionale della Ricerca. ITAE; ItaliaFil: Bonesi, Alejandro Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Triaca, Walter Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Castro Luna Berenguer, Ana Maria del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Baglio, V.. Centro Nazionale della Ricerca. ITAE; Italia; ItaliaFil: Aricò, A. S.. Centro Nazionale della Ricerca. ITAE; Italia; Itali

Protective effect of Hypericum calabricum Sprengel on oxidative damage and its inhibition of nitric oxide in lipopolysaccharide-stimulated RAW 264.7 macrophages

The present study shows for the fi rst time the phenolic composition and the in vitro properties (antioxidant and inhibition of nitric oxide production) of Hypericum calabricum Sprengel collected in Italy. The content of hypericins (hypericin and pseudohypericin), hyperforin, fl avonoids (rutin, hyperoside, isoquercetrin, quercitrin, quercetin and biapigenin) and chlorogenic acid of H. calabricum, have been determined. The ethyl acetate fraction from the aerial parts of H. calabricum exhibited activity against the radical 1,1-diphenyl-2picrylhydrazyl (DPPH) with IC 50 value of 1.6 μg/ml. The test for inhibition of nitric oxide (NO) production was performed using the murine monocytic macrophage cell line RAW 264.7. The ethyl acetate fraction had signifi cant activity with an IC 50 value of 102 μg/ml and this might indicate that it would have an anti-infl ammatory effect in vivo

Synthesis, Characterization and Electrocatalytic Activity of Bi- and Tri-metallic Pt-Based Anode Catalysts for Direct Ethanol Fuel Cells

Three Pt-based anode catalysts supported on Vulcan XC-72R (VC) were prepared by using a modified polyol process. These materials were characterized and tested by X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF) and Transmission Electron Microscopy (TEM). XRD and TEM analysis indicated that especially the ternary anode catalysts consisted of uniform nanosized particles with sharp distribution. The Pt lattice parameter was smaller, in the ternary PtSnIr catalyst whereas it increased with the addition of Sn and Rh, in the corresponding binary and ternary catalysts. Cyclic voltammetry (CV) measurements showed that Sn, Ir and Rh may act as promoter of Pt enhancing ethanol electro-oxidation activity. It was found that the direct ethanol fuel cell (DEFC) performances were significantly improved with these modified anode catalysts. This effect on the DEFC performance is attributed to the so-called bi-tri-functional mechanism and to the electronic interaction between Pt and additives. The performance increased significantly with the temperature. However, it was also possible to observe some decay with time for all catalysts due to the formation of surface poisons, probably consisting in CO-like species. At 60 °C, the PtSnIr catalyst showed the best performance, as a result of a proper morphology and promoting effectFacultad de Ciencias ExactasInstituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Synthesis, Characterization and Electrocatalytic Activity of Bi- and Tri-metallic Pt-Based Anode Catalysts for Direct Ethanol Fuel Cells

Three Pt-based anode catalysts supported on Vulcan XC-72R (VC) were prepared by using a modified polyol process. These materials were characterized and tested by X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF) and Transmission Electron Microscopy (TEM). XRD and TEM analysis indicated that especially the ternary anode catalysts consisted of uniform nanosized particles with sharp distribution. The Pt lattice parameter was smaller, in the ternary PtSnIr catalyst whereas it increased with the addition of Sn and Rh, in the corresponding binary and ternary catalysts. Cyclic voltammetry (CV) measurements showed that Sn, Ir and Rh may act as promoter of Pt enhancing ethanol electro-oxidation activity. It was found that the direct ethanol fuel cell (DEFC) performances were significantly improved with these modified anode catalysts. This effect on the DEFC performance is attributed to the so-called bi-tri-functional mechanism and to the electronic interaction between Pt and additives. The performance increased significantly with the temperature. However, it was also possible to observe some decay with time for all catalysts due to the formation of surface poisons, probably consisting in CO-like species. At 60 °C, the PtSnIr catalyst showed the best performance, as a result of a proper morphology and promoting effectFacultad de Ciencias ExactasInstituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

2-(6-Methyl-2,3,4,9-tetra­hydro-1H-carbazol-1-yl­idene)propane­dinitrile

In the title compound, C16H13N3, the cyclo­hexene ring adopts a sofa conformation. An intra­molecular N—H⋯N hydrogen bond generates an S(7) ring motif. In the crystal, the mol­ecules are linked by pairs of N—H⋯N inter­actions, forming centrosymmetric dimers with an R 2 2(14) motif

6-Bromo-2-[(E)-thio­phen-2-yl­methyl­idene]-2,3,4,9-tetra­hydro-1H-carbazol-1-one

In the title compound, C17H12BrNOS, the cyclo­hexene ring deviates only slightly from planarity (r.m.s. deviation for non-H atoms = 0.047 Å). In the crystal, the mol­ecules are linked into centro­symmetric R 2 2(10) dimers via pairs of N—H⋯O hydrogen bonds. The thio­phene ring is disordered over two positions rotated by 180° and with a site-occupation factor of 0.843 (4) for the major occupied site