Étude phytochimique et évaluation de l’activité anti-oxydante de Thymus CIliatus ssp. Coloratus

Thymus ciliatus ssp. Coloratus, plante aromatique, spontanée et répandue en régions méditerranéennes et dans le nord de l’Algérie est très utilisée par les populations locales pour ses vertus médicinales. Les tests phytochimiques appliqués au Thymus ciliatus ssp coloratus ont montré la présence de quelques familles de composés chimiques et notamment les flavonoïdes. L'activité antioxydante in vitro de l’extrait de flavonoïdes a été évaluée par la technique de réduction du fer « FRAP » (ferric reducing antioxydant power) et par le test de DPPH. La première méthode a montré que la fraction acétate d’éthyle de la partie aérienne a une capacité à réduire le fer plus marquée que celles de l’acide ascorbique et le BHA et que celle des racines, est nettement inférieure. Quant aux fractions butanoliques des flavonoïdes de la partie aérienne et des racines, elles ont une capacité à réduire le fer largement inférieure à celles de l’acide ascorbique et le BHA. L’activité antioxydante, obtenue par la second procédé et relative à la fraction acétate d’éthyle des flavonoïdes de la partie aérienne de la plante est plus importante (I.C₅₀=0,85 mg/mL) que celles obtenues à partir d’antioxydants utilisés dans les industries alimentaire et pharmaceutique en l’occurrence l’acide ascorbique (I.C₅₀ = 1,12 mg/mL) et le BHA (I.C₅₀=1,61 mg/mL).Mots-clés : Thymus coloratus, activité antioxydant, flavonoïde, FRAP, DPPH.Phytochemical study and evaluation of the antioxidant activity of thymus ciliatus ssp. Coloratus Thymus ciliatus ssp. coloratus, aromatic plant, spontaneous and widespread in the Mediterranean and in northern Algeria is widely used by local people for its medicinal properties. Phytochemical tests applied for Thymus sciliatus ssp coloratus showed the presence of several families of chemical compounds including flavonoïds. The in vitro antioxidant activity of flavonoïds extract was evaluated by the iron reduction technique "FRAP" (ferric reducing antioxidant power) and DPPH test. The first method showed that the ethyl acetate fraction of the aerial part has an ability to reduce the iron greater than ascorbic acid and BHA and the roots, is significantly lower. As for butanol fractions of flavonoïds from the aerial part and roots, they have an ability to reduce iron significantly lower than those of ascorbic acid and BHA. The antioxidant activity obtained by the second method and on the ethyl acetate fraction of flavonoïds from the aerial part of the plant is more important (I.C₅₀ = 0.85 mg / mL) than those obtained from 'antioxidants used in food and pharmaceutical industries namely ascorbic acid (I.C₅₀ = 1.12 mg / mL) and BHA (I.C₅₀ = 1.61 mg / mL).Keywords : Thymus coloratus, antioxidant activity, flavonoïd, FRAP, DPPH

Carcinome métaplasique du sein avec différenciation osseuse extensive: À propos d’un cas

Le carcinome métaplasique du sein est une entité rare et bien individualisé par l'OMS. Il représente moins de 1 % des cancers invasifs du sein et constitue un groupe tumoral hétérogène soit purement épithélial soit à doublecontingent épithélial et mésenchymateuse. Le carcinome métaplasique avec différenciation osseuse extensive est très rare. Il représente 0.2% des carcinomes du sein. Nous rapportant un cas exceptionnel d'un carcinome métaplasique du sein avec différenciation osseuse extensive chez une patiente de 53 ans. A travers ce cas et une revue de la littérature, les caractéristiques anatomo-cliniques, radiologique, thérapeutiques et évolutives seront discutées

Relationships between crystalline structure and dielectric properties in Sr2Sm(1-x)NdxTi2Nb3O15 ceramics

In this study, tungsten-bronze type materials of Sr2Sm(1-x)NdxTi2Nb3O15 composition (x=0; 0,25; 0,5; 0,75 and 1) were elaborated by classical solid-state reaction. The structural characterization demonstrate that these compounds present tetragonal symmetry, using two space groups P4bm (N°100) and P4/mbm (N°127) respectively. The lattice parameters are a=b≈12,2Ǻ; c≈3,8Ǻ; V≈579,03Ǻ and Z=2. In this compounds, Ti and Nb cations show obvious off-center displacements along the c axis in both the Ti/Nb(1)O6 and the Ti/Nb(2)O6 octahedra. Besides, the unequal Ti/Nb(2)–O bonds length in the equatorial plane of Ti/Nb(2)O6 octahedra indicates the displacement of the Ti/Nb(2) cations in the ab plane, and no displacement of the Ti/Nb(1) cations exists in the ab plane. The results show that this material has two types of octahedral, first octahedron with little deformation around the Ti1/Nb1 and the second octahedron are more distorted around the Ti2/Nb2. The measurements of permittivity and dielectric losses of the ceramic samples performed between 25°C and 700°C (100Hz to 1MHz), high dielectric constants (εr=127 ~ 194) and low dielectric losses (tan(δ) around 10-4 at 1MHz) were found. The maximum value of the dielectric constant is obtained for x=0 (εr=194). The Curie temperature Tc decreases from 332 to 246°C as a function of the substitution of the samarium by neodymium. Detailed microstructural analysis by scanning electron microscope (SEM) and (EDS) for this compounds are also investigated

Composición química parcial y actividad antimicrobiana de extractos de Daucus critinus Desf

The chemical composition of fatty acids and the unsaponifiable fraction of the roots, leaves and stems from Daucus crinitus Desf. were, determined using gas chromatography (GC) and gas chromatography-Mass Spectrometry (GC-MS). The fatty acid fractions of different organs (leaves, stems and roots) were characterized by lauric acid (17.9, 17.5 and 18.1 % respectively) and other long chain fatty acids (until C22). Qualitative and quantitative differences were reported between the unsaponifiable fractions of different organs from D. crinitus. The unsaponifiable fractions of the leaves, roots and stem showed high amounts of aliphatic components (83.4%, 87.2% and 91.4%, respectively). The monoterpen, diterpen and sesquiterpen components were only present in small percentages. The antimicrobial properties of the D. critinus extracts were tested on four different microorganisms. These extracts were found to be active against Bacillus cereus, Staphylococcus aureus, Escherichia coli and Candida albicans.La composición química de los ácidos grasos y la fracción insaponificable de raíces, hojas, y tallos de Daucus crinitus Desf. fueron establecidas utilizando cromatografía de gases (GC) y cromatografía de gases-espectrometría de masas (GC-MS). La fracción de ácidos grasos de los diferentes órganos (hojas, tallos y raíces) se caracterizó por el ácido láurico (17.9, 17.5 y 18.1% respectivamente) y otros ácidos grasos de cadena larga (hasta C22). Diferencias cualitativas y cuantitativas se registraron entre las fracciones insaponificable de los diferentes órganos de D. crinitus. De hecho, las fracciones insaponificable de la raíz, de la hoja y del tallo mostraron cantidades altas de componentes alifáticos (83.4%, 87.2% y 91.4%, respectivamente). Los componentes monoterpénicos, diterpénicos y sesquiterpénicos solo estuvieron presentes en un pequeño porcentaje. Las propiedades antimicrobianas de los extractos de D. critinus fueron ensayadas en cuatro microorganismos diferentes. Estos extractos fueron activos contra Bacillus cereus, Staphylococcus aureus, Escherichia coli y Candida albicans

Pesticide exposure in honey bees results in increased levels of the gut pathogen Nosema

Global pollinator declines have been attributed to habitat destruction, pesticide use, and climate change or some combination of these factors, and managed honey bees, Apis mellifera, are part of worldwide pollinator declines. Here we exposed honey bee colonies during three brood generations to sub-lethal doses of a widely used pesticide, imidacloprid, and then subsequently challenged newly emerged bees with the gut parasite, Nosema spp. The pesticide dosages used were below levels demonstrated to cause effects on longevity or foraging in adult honey bees. Nosema infections increased significantly in the bees from pesticide-treated hives when compared to bees from control hives demonstrating an indirect effect of pesticides on pathogen growth in honey bees. We clearly demonstrate an increase in pathogen growth within individual bees reared in colonies exposed to one of the most widely used pesticides worldwide, imidacloprid, at below levels considered harmful to bees. The finding that individual bees with undetectable levels of the target pesticide, after being reared in a sub-lethal pesticide environment within the colony, had higher Nosema is significant. Interactions between pesticides and pathogens could be a major contributor to increased mortality of honey bee colonies, including colony collapse disorder, and other pollinator declines worldwide

Mechanical recycling of polylactide, upgrading trends and combination of valorization techniques

The upcoming introduction of polylactides in the fractions of polymer waste encourages technologists to ascertain its valorization at the best quality conditions. Mechanical recycling of PLA represents one of the most cost-effective methodologies, but the recycled materials are usually directed to downgraded applications, due to the inherent thermomechanical degradation affecting its mechanical, thermal and rheological performance. In this review, the current state of mechanical recycling of PLA is reported, with special emphasis on a multi-scale comparison among different studies. Additionally, the applications of physical and chemical upgrading strategies, as well as the chances to blend and/ or composite recycled PLA are considered. Moreover, the different valorization techniques that can be combined to optimize the value of PLA goods along its life cycle are discussed. Finally, a list of different opportunities to nurture the background of the mechanical recycling of PLA is proposed, in order to contribute to the correct waste management of PLA wastes