Batch experiments on the removal of U(VI) ions in aqueous solutions by adsorption onto a natural clay surface

The efficiency of the clay from Bikougou deposit (Gabon) as adsorbent for removing U(VI) ions dissolved artificially in aqueous solutions has been studied. Batch experiments have been performed for that by varying pH, U(VI) ions solution concentration, ionic solution strength, clay dosage, interaction duration and temperature. The U(VI) ions uptake per unit mass of clay, increases with the increase in pH (2-7), U(VI) ions solution concentrations and temperature. It decreases with the increase in ionic solution strength and clay dosage. The adsorption isotherm is best described by Dubinin-Kaganer-Radushkevich isotherm model. The kinetics of the adsorption of U(VI) ions on clay surface follows the pseudo-second-order kinetic model and the interaction realized spontaneously is exothermic. The mean values of thermodynamic constants ?H°, ?S° and ?G° obtained at 308k are respectively-62.54kJ/mol, -0.18kJ/K.mol and -8.68 kJ/mol. Keywords: Adsorption capacity, adsorbent, U(VI) ions solution, isotherm model, distribution constan

Chemical composition of a standard sugarcane wine of Saccharum officinarum Linn from Woleu-Ntem, Gabon

The alcohol level and phytochemical screening of sugarcane wine of Saccharum officinarum Linn were studied. The proof of sugarcane wine was evaluated at more than 14% (v/v). Studies of phytochemical constituents showed the presence of alkaloids, polyphenols, tannins, reductor compounds and flavonoids. Many of these compounds are benefit for the human health. Presence of polyphenols and flavonoids allow the wine to get antioxidant properties

Regulation de la lactase intestinale chez le rat adulte

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Antiproliferative Effect Of Alcoholic Extracts Of Some Gabonese Medicinal Plants On Human Colonic Cancer Cells

Extracts from Piptadeniastrum africanum Brenan (Mimosaceae), Petersianthus macrocarpus (Breauv) L. (Lecydaceae), Cissus debilis Planch (Vitaceae) and Dieffenbachia seguine Jacq. (Araceae) were tested in vitro for their antiproliferative activity on human colon cancer cell line (CaCo-2). The highest antiproliferative activities were obtained with the alcoholic extracts of the roots of Piptadeniastrum africanum (G-PAR), the leaves of Petersianthus macrocarpus (G-PMF) and the stem of Cissus debilis (G-CDL), with 50% inhibition concentrations (IC50) of 15 μg/ml, 17 μg/ml and 25 μg/ml respectively. Only one extract (leaves of Dieffenbachia seguine (G-DSF)) exhibited weak antiproliferative activity with 50% inhibition concentration (IC50) higher than 50 μg/ml

Chemical composition, antioxidant and antimicrobial activities of stem barks of Englerina gabonensis Engler and Sterculia tragacantha Lindl from Gabon

Aim of this work was to evaluate the phytochemical constituents, antioxidant and antimicrobial potential of water-acetone, water-ethanol and water extracts of Englerina gabonensis and Sterculia tragacantha.Presence of phenols was evaluated to estimate the effects of plants on microbial diseases. Water-acetone, water-ethanol and water extracts were examined for antioxidant activities. All plant extracts were tested against six reference strains, eleven clinical isolates and two fungal strains.Phenolic content were highest in the water-acetone and water-ethanol extracts from Englerinagabonensis in comparison with Sterculia tragacantha.The AAI (Antioxidant Activity Index)of water-acetone and water-ethanol extracts of Englerina gabunensis are superiors with 2. Plant extracts of Sterculia tragacantha show weak antioxidant activity (AAI < 0.5).The aqueous extract of Englerina gabonensis has a bactericidal effect on Salmonella Spp. Water-ethanol extract is bactericidal on Bacillus cereus LMG 13569 BHI, Salmonella Sppand Neisseria meningitides. Water-acetone extract presents a bactericidal activity on Enterococcus faecalis103907 CIP, Escherichi coli, Staphylococcus aureus, Acinetobacter baumanniiand Neisseria meningitides.Our results suggest that Englerina gabonensis extracts contain greater antioxidant and antimicrobial properties than Sterculia tragacantha extracts

Toxicity, Antibacterial, and Phytochemical Analyses of Antrocaryon klaineanum Pierre Extracts

Medicinal plants are traditionally used in Gabon to treat several types of illnesses. The study’s purpose was to determine the toxic, antibacterial, and anti-inflammatory effects of Antrocaryon klaineanum Pierre extracts and to characterize their phytochemical compounds. Toxicity was evaluated on frog tadpoles (Phrynobatrachus africanus Hallowell). The microorganism susceptibility test was performed by the diffusion method, while minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated using the microdilution technique. Anti-inflammatory activity was tested through protein denaturation and membrane stabilization methods. Chromatography and molecular network techniques were used to characterize chemical compounds. The lethality test showed that the lethal concentration (LC50) increased from 110.03 ± 1.25 to 15.86 ± 2.21 μg/mL after 24 and 96 hours of exposure. In tadpoles exposed to 7.81 μg/mL extract, the first mortalities (12.5%) were observed on the fifth day of exposure. A relative decrease in mature erythrocytes exposed to plant extracts was observed. The antibacterial activity shows that the Ak F2, Ak F3, and Ak F4 fractions (from the water-ethanol crude extract) gave the greatest antibacterial activities compared to the other extracts. The water, water-acetone, and water-ethanol extracts showed good inhibition of denaturation. The haemolysis test shows that the extracts exhibited good anti-inflammatory activities. Phytochemical characterisation revealed four major compounds, including monogallate epicatechin and hydroxy-ergostadian. The molecular network revealed five main clusters. Our study shows that A. klaineanum Pierre could be a promising natural product for the isolation of molecules with potential biological activities