This study describes the chemical composition and the antibacterial, antifungal and antioxidant activities of the essential oil extracted from aerial parts of the Algerian Eryngium tricuspidatum L., obtained by hydrodistillation and analysed by using the combination of gas chromatography (GC) and GC/mass spectrometry. A total of 63 compounds were identified accounting for 93.1% of the total oil. Chemical composition of oil was characterised by a high proportion of oxygenated sesquiterpenes (49.6%) among which α-bisabolol (32.6%) was the predominant compound. The sesquiterpene hydrocarbons represent the second major fraction (31.9%) with α-curcumene (6.5%) being the predominant one. Antibacterial and antifungal activities of the oil were tested using the micro-well determination of minimum inhibitory concentration (MIC) assay against eleven bacteria and two Candida species. It was found that the aerial parts of E. tricuspidatum exhibited interesting antibacterial and anticandidal activities (MIC = 9 μg/mL against several strains of bacteria and MIC = 4.6 μg/mL against Candida albicans). The antioxidant effect of this oil was evaluated using the 2,2-diphenyl-l-1-picrylhydrazil (DPPH) and ferric reducing antioxidant power (FRAP) assays. Results revealed significant activities (DPPH method: IC₅₀ = 510 μg/mL; FRAP assay: reducing power of oil increases from 0.0188 at 5 μg/mL to 0.5016 at 1000 μg/mL).

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International audienceObjective: To assess the antimicrobial and antioxidant activity of the essential oil and ethaniol extract of the aerial parts of Calycotome villosa subsp. intermedia growing in the West Northern region of Algeria. Methods: Chemical composition of essential oils obtained by hydrodistillation from areal parts of Calycotome villosa subsp intermedia was investigated using gas chromatography (retention indices) and gas chromatography-mass spectrometry while the antimicrobial activities were determinate by paper disc diffusion method and minimum inhibitory concentration assay tested against four bacterial strains and one yeast and antioxidant activity was evaluated as a free radical scavenging capacity (RSC). Results: Essential oils were dominated by non-terpenic compounds and fatty acids. Howeverthe phenylpropanoid monoterpenes and sesquitepene components were only present in small percentages. The most important antibacterial activity of essential oil was expressed on Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumoniae and Salmonella typhimurium. Antioxidant activity was evaluated as a RSC. RSC was assessed by measuring the scavenging activity of essential oil and ethanol extract on 1,1-diphenyl-2-picrylhydrazil (DPPH). Investigated ethanol extract reduced the DPPH radical formation (IC50=68 μg/mL). Conclusions: Results in this experiment indicate that the essential oil and the ethanol extract display antibacterial activity against two Gram-positive bacteria and activity to a lesser extent against two Gram-negative species. They may be a new potential source of components, which ar likely to have impact on human health

Silver nanoparticles (AgNPs) at different amounts have successfully been deposited, by simple impregnation on the titanium dioxide (TiO 2) developed by the hydrothermal method. A textural and structural study of prepared materials was conducted using different analysis techniques, namely X-Ray Diffraction (XRD), Diffuse Reflectance UV-Vis (DR/UV-Vis) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, in addition to the Brunauer-Emmett-Teller (BET) method. The nanostructured prepared materials were tested for their antibacterial activity on four strains, i. e. two Gram-negative (GÀ) bacteria, namely Escherichia coli ATCC 8739 and A. baumanni ATCC 19606, and two Gram positive (G +) bacteria, i. e. S.aureus ATCC 6538 and E.cloacae ATCC 13047. The antioxidant effect was also tested on the reference radical DPPH°(2,2-diphenyl-1-picrylhydrazyle). AgNPs supported on TiO2 showed good antibacterial activity against the four selected strains. In addition, the minimum inhibitory concentration (MIC) was observed in the case of the low-grade silverdoped catalyst (0.1 % Ag/TiO2). Differently from the antibacterial activity, the antioxidant effect of the prepared materials was found to be pronounced in the cases of materials with high silver contents for which there was degradation of the radical in comparison with the one of the reference acid.