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

Antioxidant activities and phenolic contents of the methanol extracts of the stems of Acokanthera oppositifolia and Adenia gummifera

Abstract Background Acokanthera oppositifolia Lam (family: Apocynaceae) is a shrub or small tree with white latex, and the leaves of this plant are used in the form of a snuff to treat headaches and in infusions for abdominal pains and convulsions and septicaemia. Adenia gummifera Harv of the family Passifloraceae is a distinctive woody climber whose infusions are used as emetics and are said to help with some forms of depression. Lipid peroxidation has gained more importance today because of its involvement in pathogenesis of many diseases. Free radicals are the main agents in lipid peroxidation. Antioxidants thus play an important role of protecting the human body against damage by the free radicals. Plants containing phenolic compounds have been reported to possess strong antioxidant properties. Methods The antioxidant activities and phenolic contents of the methanol extracts of the stems of Acokanthera oppositifolia and Adenia gummifera were evaluated using in vitro standard procedures. Spectrophotometry was the basis for the determinations of total phenol, total flavonoids, flavonols, and proanthocyanidins. Tannins, quercetin and catechin equivalents were used for these parameters. The antioxidant activities of the stem extract of Acokanthera oppositifolia were determined by the 2,2'-azinobis-3- ethylbenzothiazoline-6-sulfonic acid (ABTS), 1,1-Diphenyl-2-picrylhydrazyl (DPPH), and ferrous reducing antioxidant property (FRAP) methods. Results The results from this study showed that the antioxidant activities of the stem extract of Acokanthera oppositifolia as determined by the 1,1-Diphenyl-2-picrylhydrazyl (DPPH), and ferrous reducing antioxidant property (FRAP) methods, were higher than that of Adenia gummifera. The levels of total phenols and flavonols for A. oppositifolia were also higher. On the other hand, the stem extract of Adenia gummifera had higher level of total flavonoids and proanthocyanidins than that of Acokanthera oppositifolia. The 2, 2'-azinobis-3- ethylbenzothiazoline-6-sulfonic acid (ABTS) activities of the 2 plant extracts were similar and comparable to that of BHT. Conclusion Thus, the present results indicate clearly that the extracts of Acokanthera oppositifolia and Adenia gummifera possess antioxidant properties and could serve as free radical inhibitors or scavengers, acting possibly as primary antioxidants. This study has to some extent validated the medicinal potential of the stems of Acokanthera oppositifolia and Adenia gummifera.</p

Assessment of the medicinal potentials of the methanol extracts of the leaves and stems of Buddleja saligna

<p>Abstract</p> <p>Background</p> <p><it>Buddleja saligna </it>Willd (Loganiaceae) is a small to medium-sized evergreen tree; trunk short, often gnarled and crooked; crown dense, rounded or domed-shaped; foliage greyish green. The wild olives are traditionally used to lower blood pressures in many parts of the world. In southern Africa, bark and leaf decoctions are used to treat colic, coughs, colds, sore eyes, urinary problems and as purgatives.</p> <p>Methods</p> <p>The antibacterial, antioxidant activities and phenolic contents of the methanol extracts of the leaves and stems of <it>Buddleja saligna </it>were evaluated using <it>in vitro </it>standard methods. Spectrophotometry was the basis for the determinations of total phenol, total flavonoids, flavonols, and proanthocyanidins. Tannins, quercetin and catechin equivalents were used for these parameters. The antioxidant activities of the leaves and stem extracts of <it>Buddleja saligna </it>were determined by ABTS, DPPH, and ferrous reducing antioxidant property (FRAP) methods. Laboratory isolates of 10 bacteria species which included five Gram-positive and five Gram-negative strains were used to assay for antibacterial activity of this plant.</p> <p>Results</p> <p>The antioxidant activities of the leaves as determined by the ABTS and DPPH were similar to that of the stem. The flavonoids and the flavonols contents of the leaves were higher than that of the stem but the total phenols, proanthocyanidins and FRAP activities were higher in the methanol extracts of the stem. The extracts did show activity against both Gram-positive and Gram-negative bacteria. For instance, while the methanol extract of the leaves showed good activities on all the organisms except <it>Serratia marcescens </it>and <it>Pseudomonas aeruginosa </it>at MICs of between 2.5 and 5.0 mg/ml, the extract of the stem only showed activities on <it>Bacillus cereus, Streptococcus pyrogens </it>and <it>Pseudomonas aeruginosa </it>at the same concentration.</p> <p>Conclusion</p> <p>The results from this study indicate that the leaves and stem extracts of <it>Buddleja saligna </it>possess antioxidant properties and could serve as free radical inhibitors or scavenger or, acting possibly as primary antioxidants. Although, the antibacterial properties of <it>Buddleja saligna </it>are not as effective as the standard drugs-Chloramphenicol and Streptomycin, they still possess some activity against bacterial strains used in this study. <it>Buddleja saligna </it>may therefore be a good candidate for functional foods as well as pharmaceutical plant-based products.</p

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

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

International audienc