Antiplasmodial Efficacy of Fruit Extracts and Cladodes of Opuntia ficus-indica

Abstract Development of antimalarial drugs from medicinal plants continues to be a very appealing process. Therapeutic effects of the ethyl acetate cladodes an extract of Opuntia ficus-indica has been evaluated in Plasmodium berghei infection in mice. The extract of the Opuntia ficus-indica has an in vitro activity against the parasite, the average parasitemia of 4.7% from two wells at 24 hour concerning a blood control containing only 7.5%. The reduced parasitemia extract batch has proved to process more efficiently than the control group with olive oil, with 3.2% parasitemia on day 5 and 30% on day 8. However, the average parasitemia of the treated animals with the extract has been lower than the control detected one which showes very low levels of parasitemia (5%, 3.7% and 6.7%). This study presents an in vitro and in vivo evaluation of the antiplasmodial effects of two-plant extracts of Opuntia ficus-indica commonly used in Tunisia as a folk medicine. It is concluded that the ethyl acetate cladodes extract of Opuntia ficus-indica prove to be potentially useful for the development of antimalarial drug. Keywords: Antimalaria, Percentage suppression, Opuntia ficus-indica, Plasmodium Berghei, Parasitaemi

Silver nanoparticle embedded copper oxide as an efficient core–shell for the catalytic reduction of 4-nitrophenol and antibacterial activity improvement

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Co-precipitation synthesis and characterization of tin-doped α-Fe 2 O 3 nanoparticles with enhanced photocatalytic activities

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Synthesis of tin oxide activated by DAN grafting and Mo nanoparticle insertion for optoelectronic properties improvement

International audienceTin oxide (SnO2) was synthesized via a co-precipitation method and activated by 1,5 diaminonaphthalene (DAN) grafting and molybdenum nanoparticles (Mo-NPs) incorporation. The resulting SnO2–DAN–Mo nanocomposites were characterized by X-ray diffraction, transmission electron microscopy, diffuse reflectance and FTIR spectrophotometry, photoluminescence spectroscopy and complex impedance spectroscopy measurements. The surface-grafting of DAN within mesopores was confirmed by Fourier-transform infrared spectroscopy. The XRD and TEM studies showed a dominant tetragonal structure. The dispersion of fine Mo-NPs on the surface of the matrices, produced slight structural compaction. The crystallite size decreased with the insertion of DAN and Mo-NPs. The photoluminescence study revealed the presence of oxygen vacancies and that the PL intensity strongly depends on DAN grafting and Mo-NPs insertion. In addition, both the incorporation of Mo-NPs and DAN grafting appear to be responsible for the changes in the conductance and relaxation phenomenon. The effects of surface groups of SnO2–DAN–Mo and charge transfer were found to be almost proportional to the capacitance. The above properties make these nanocomposites efficient electrode materials for green energy storage

Synthesis and properties of ZnO-HMD@ZnO-Fe/Cu core-shell as advanced material for hydrogen storage

International audienceIn this paper, a new synthetic strategy towards functionalized ZnO-HMD@ZnO-Fe/Cu core-shell using sol-gel process modified by chemical grafting of hexamethylenediamine (HMD) on the core and in-situ dispersion of Cu0/Fe0 as metallic nanoparticles (M-NPs) on the shell. The as-prepared core-shell materials were fully characterized by transmission electron microscopy, X-ray powder diffractometry, diffuse reflectance and FT-IR spectrophotometery, photoluminescence, and complexes impedance spectroscopy measurements. The XRD patterns agreed with that of the ZnO typical wurtzite structure, indicating good crystallinity of ZnO-HMD@ZnO-Fe/Cu, with the presence of Fe0 and Cu0 phases. Hexamethylenediamine grafting and M-NPs insertion were highly activated and enhanced the core and shell interface by the physiochemical interaction. After functionalization, luminescence intensities and electrical properties of both core and core-shell nanoparticles are improved, indicating the effects of the surface groups on the charge transfer of ZnO-HMD@ZnO-Fe/Cu. The hydrogen capacity retention was depended strongly on the composition and structure of the obtained core-shell. Iron/Copper-loaded ZnO-HMD@ZnO materials exhibited the highest capacity for hydrogen storage. The excellent stability and performance of the ZnO-HMD@ZnO-Fe/Cu core-shell make it an efficient candidate for hydrogen storage

Microwave-assisted polyol synthesis of mesoporous Ta doped mixed TiO 2 /SnO2 : Application for CO2 capture

International audienceTantalum-decorated mixed oxides (Ti0.5Sn0.5O2) was successfully synthesized, using a microwave-assisted polyol process (MAP) and triethylene glycol as a solvent, in a much shorter time than conventional heating. The newly-synthesized nanocomposites materials were used to make resistive semiconductor gas sensors to detect CO2. The powders were investigated using X-ray diffractometry, transmission electron microscopy and N2 physisorption. The X-ray diffraction patterns of the samples confirm that TiO2 is in the anatase phase and SnO2 and Ti0.5Sn0.5O2 are in the cassiterite phase. The TEM images showed uniform isotropic morphologies with average sizes close to 10 nm. The optimized sensor, based on TiO2/SnO2/Ta showed promising performances towards CO2 capture, ensuring a high response and fast dynamics at an operating temperature of 20 °C. The CO2 adsorption capacity was also remarkably increased from 0.58 mmol g−1 for TiO2 alone to 0.90 mmol g−1 for the Ti0.5Sn0.5O2. This work brings insights into a new way of limiting atmospheric pollution using mixed-oxide nanoparticles

Synthesis and characterization of SnO2, TiO2 and Ti0.5Sn0.5O2 nanoparticles as efficient materials for photocatalytic activity

International audienceThis work reports the synthesis of polydispersible SnO2, TiO2 and Ti0.5Sn0.5O2 nanoparticles via microwave-assisted polyol as an efficient method using diethylene glycol (DEG) and triethylene glycol (TREG) as solvent. The properties of as-prepared samples were investigated by X-ray diffractometry, transmission electron microscopy, diffuse reflectance and FTIR spectrophotometery, photoluminescence spectroscopy and N2 physisorption. The X-ray diffraction patterns of the samples were indexed on the anatase phase of TiO2 and cassiterite phase of SnO2 and Ti0.5Sn0.5O2. The TEM images show uniform isotropic morphologies with average sizes close to10 nm. The band gap is reduced for Ti0.5Sn0.5O2 and enhances visible light absorption, a shift resulting in the absorption threshold towards the visible spectral range, compared to pure titania and tin. Slight shifts to longer wavelength are attributed to the change in the acceptor’s level induced by the mixture of both oxides. The evaluation of the photocatalytic activity is carried out using indigo carmine (IC) as model of chemical pollutants in UV irradiation conditions. The photocatalytic decolorization of the dye follows a pseudo-first-order kinetics and the constant apparent rate was increased with the increase of the tin oxide content up to 50%

Cu0-loaded SBA-15@ZnO with improved electrical properties and affinity towards hydrogen

International audienceA core-shell material was prepared using SBA-15 crystallites as cores for the growth of a ZnO shell, followed by Cu0 dispersion. The resulting Cu/SBA-15@ZnO nanostructure displayed higher specific surface area (SSA) and higher number of smaller pores as compared to the starting materials. Dispersion of fine Cu0NPs induced a compaction of the host matrice and a marked decay of the hydrophilic character, explained in terms of the involvement of terminal hydroxyl groups in competitive HO:Cu interaction at the expense of H-bridges with water. Heating at 400–450 °C seems to trigger ZnO dehydroxylation with possible self-polycondensation and/or the formation of Si-O-Zn bridges. This is an additional explanation of the significant SSA increase and decrease in the average pore diameter. Both ZnO and Cu0NP incorporation induced shifts in the UV–vis absorption band towards higher wavelengths, indicating a decrease in the optical band gap energy and an improvement of the conductance properties. As compared to ZnO, Cu0NPs produced stronger improvement of the conductance, which was found to increase with higher frequencies. Cu/SBA-15@ZnO also displayed higher affinity towards hydrogen as compared to SBA-15@ZnO and SBA-15 at ambient conditions. These outstanding properties combined to an appreciable thermal stability are worth to be prone to deeper investigations, because they can open promising prospects for Cu/SBA-15@ZnO as sensor, electrode material, electrocatalyst and/or hydrogen capture matrice

Michael addition of 1,3-dicarbonyl compounds catalyzed by iron oxide nanoparticles

International audienceSeveral iron oxides nanoparticles (Fe2O3@Fe2O3, Fe°@Fe2O3, GO@Fe2O3 and calcinated Fe2O3) have been assessed as catalysts in the 1,4-addition of a cyclic β-ketoester onto methyl vinyl ketone under neat conditions. It appeared that calcinated Fe2O3NP are efficient catalysts at 1 mol% loading for the Michael addition of 1,3-dicarbonyl compounds onto various enones