Olive leaf extract activity against Candida albicans and C. dubliniensis – the in vitro viability study

Olive leaf extract is characterized by a high content of polyphenols (oleuropein, hydroxytyrosol and their derivatives), which is associated with its therapeutic properties. The objective of the present research was to evaluate the antifungal activity of olive leaf aqueous extract against Candida albicans ATCC 10231 and C. dubliniensis CBS 7987 strains. Minimum inhibitory concentration (MIC) of the extract was determined by several in vitro assays. The extract showed a concentration dependent effects on the viability of C. albicans with MIC value of 46.875 mg mL–1 and C. dubliniensis with MIC value 62.5 mg mL–1. Most sensitive methods for testing the antifungal effect of the extract were the trypan blue exclusion method and fluorescent dye exclusion method while MIC could not be determined by the method according to the EUCAST recommendation suggesting that herbal preparations contain compounds that may interfere with this susceptibility testing. The fluorescent dye exclusion method was also used for the assessment of morphological changes in the nuclei of the treated cells. According to the obtained results, olive leaf extract is less effective against the tested strains than hydroxytyrosol, an olive plant constituent tested in our previous study

Antioxidant activities of sulfated polysaccharides from brown and red seaweeds

The in vitro antioxidant activities of the following six sulfated polysaccharides were investigated: iota, kappa and lambda carrageenans, which are widely used in the food industry, fucoidan (homofucan) from the edible seaweed Fucus vesiculosus and fucans (heterofucans) F0.5 and F1.1 from the seaweed Padina gymnospora. With respect to the inhibition of superoxide radical formation, fucoidan had an IC50 (the half maximal inhibitory concentration) of 0.058 mg·mL−1, while the IC50 for the kappa, iota and lambda carrageenans were 0.112, 0.332 and 0.046 mg·mL−1, respectively. All of the samples had an inhibitory effect on the formation of hydroxyl radicals. The results of peroxidation tests showed that fucoidan had an IC50 of 1.250 mg·mL−1 and that the kappa, iota and lambda carrageenans had an IC50 of 2.753 and 2.338 and 0.323 mg·mL−1, respectively. Fucan fractions showed low antioxidant activity relative to fucoidan. These results clearly indicate the beneficial effect of algal polysaccharides as antioxidants

Fucoxanthin, a Marine Carotenoid Present in Brown Seaweeds and Diatoms: Metabolism and Bioactivities Relevant to Human Health

The marine carotenoid fucoxanthin can be found in marine brown seaweeds, the macroalgae, and diatoms, the microalgae, and has remarkable biological properties. Numerous studies have shown that fucoxanthin has considerable potential and promising applications in human health. In this article, we review the current available scientific literature regarding the metabolism, safety, and bioactivities of fucoxanthin, including its antioxidant, anti-inflammatory, anticancer, anti-obese, antidiabetic, antiangiogenic and antimalarial activities, and its protective effects on the liver, blood vessels of the brain, bones, skin, and eyes. Although some studies have shown the bioavailability of fucoxanthin in brown seaweeds to be low in humans, many studies have suggested that a dietary combination of fucoxanthin and edible oil or lipid could increase the absorption rate of fucoxanthin, and thus it might be a promising marine drug

Radiolysis influence on low alloy steel atmospheric corrosion at 80°C

International audienceThe degradation of iron-based materials by atmospheric corrosion is a well-known problem thatmay have incidence, especially for the storage of radioactive nuclear wastes. It is of importanceto evaluate the damages due to this kind of corrosion within long time-periods. One parameterwhich can influence atmospheric corrosion in the case of storage container is irradiation. Asatmospheric corrosion happens when a water film condensates at the surface of a material,radiolysis of this water film in contact with air can have for consequence the formation of acid anoxidizing species which can modify the corrosion process.As a consequence the aim of this work is to evaluate the influence of γ-irradiation onatmospheric corrosion of low alloy steel. In this goal, an experiment, called CASIMIR, has beendeveloped. During this experiment, samples of low alloy steel have been introduced into smallstainless steel container. In these ones, two different media has been introduced. The firstmedium is a small quantity of water in order to fix a relative humidity (RH) of 100 %. Thesecond medium is a melt of KH$_2$PO$_4$/ K$_2$HPO$_4$in a small quantity of water corresponding to arelative humidity of about 70% at the surface of the samples. The small containers have beenintroduced in a heating system which enables to fix a temperature of 80°C. This system has beeninstalled in an irradiation pool with three $^{60}$Co sources which fix, according to the location of thestainless steel in the system, a dose rate of 80 Gy.h$^{-1}$ or 20 Gy.h$^{-1}$ at the surface of the low alloysteel samples.After six, nine and twelve months of corrosion in these conditions some samples were extractedof the experiment and analyzed by different methods. Gravimetry after desquamation of thecorrosion layer enables to measure total corroded thickness in function of RH, dose rate andtime. As show on figure 1, after 6 month of exposure, sample aged with a RH of 100% are morecorroded than the one aged at 70%. Moreover the dose rate does not have an effect on thecorroded thickness for 20 Gy.h$^{-1}$ whereas it increases corrosion when the dose rate is equal to 80Gy.h$^{-1}$. This result is confirmed for longer times. Gas analysis after corrosion experiment haveshown that for the higher corrosion rate, oxygen was totally consumed after 6 month and revealalso a production of hydrogen. Microscopical observations also confirm the influence of doserate on atmospheric corrosion.All the results show that dose rate does not influence atmospheric corrosion until a valuebetween 20 and 80 Gy.h$^{-1}$. For a dose rate up to these thresholds, irradiation increase corrosionrate on low alloy steel in presence of high values of relative humilities.6th International Works

Radiolysis effect on Eu(III)-superplasticiser interactions in artificial cement and squeezed cement pore waters

International audienc

US/French joint research program regarding the behavior of polymer base materials subjected to beta radiation: Volume 2, Phase-2a screening tests: (Final report)

As part of the ongoing joint NRC/CEA cooperative test program to investigate the relative effectiveness of beta and gamma irradiation to produce damage in polymer base materials, ethylene propylene rubber (EPR) specimens, in slab geometry, were exposed to Cobalt-60 gamma rays and accelerator produced electron beams. Specimens were irradiated and evaluated at research facilities in the US (Sandia National Laboratories) and France (Compagnie ORIS Industrie). These tests included several electron beam energies, sample thicknesses, exposure doses, and dose rates. Based on changes in the tensile properties, of the test specimens, results of these studies suggest that material damage resulting from electron and gamma irradiations can be correlated on the basis of absorbed radiation dose

Study of concrete radiation ageing

International audienceConcrete is a durable material which is a vital part of engineering barrier for radioactive waste disposal. In many concepts of low and intermediate level waste (e.g. the French concept) and in some cases even of high level waste, concrete is planned to be used for construction of containers carrying the primary packages of the immobilized waste. Therefore, it is needed to understand the effect of gamma irradiation on concrete with respect to its durability. A joint experimental program of Czech and French research organizations CVR and CEA respectively was started in order to study the changes in the properties of cementitious composites after their exposition to gamma irradiation. Samples of cement mortars, manufactured in CVR, were divided into two sets, each of them irradiated and characterized with both CVR and CEA facilities. Samples tested in CVR were exposed to cumulative doses of 1.6 to 1.8 et61655;106 Gy with doses from 0.5 to 4.5 kGy/h, while samples in Saclay were exposed to cumulative doses of 0.72 to 3.1et61655;106 Gy with doses 0.6, 1.6 and 2.6 kGy/h, respectively. Mechanical properties of irradiated mortars were then defined by ultrasonic measurement to obtain changes in Young modulus of elasticity and by classical loading to obtain changes of flexural and compressive strength. A comparison with non-irradiated samples maintained in same environment was done. Moreover, investigation of microscopic changes in the concrete structure was executed by scanning electron microscope.Comparison of all the results can be seen in the paper

The potential effect of radiolyzed superplasticizers contained in cement-based materials on europium uptake

International audienc

US/French Joint Research Program regarding the behavior of polymer base materials subjected to beta radiation. Volume 1. Phase-1 normalization results

As part of the ongoing multi-year joint NRC/CEA international cooperative test program to investigate the dose-damage equivalence of gamma and beta radiation on polymer base materials, dosimetry and ethylene-propylene rubber (EPR) specimens were exchanged, irradiated, and evaluated for property changes at research facilities in the US (Sandia National Laboratories) and France (Compagnie ORIS Industrie). The purpose of this Phase-1 test series was to normalize and cross-correlate the results obtained by one research center to the other, in terms of exposure (1.0 MeV accelerated electrons and /sup 60/Co gammas) and postirradiation testing (ultimate elongation and tensile strength, hardness, and density) techniques. The dosimetry and material specimen results indicate good agreement between the two countries regarding the exposure conditions and postirradiation evaluation techniques employed