Trypanocidal and leishmanicidal activity of six limonoids

Six limonoids [kotschyienone A and B (1, 2), 7-deacetylgedunin (3), 7-deacetyl-7-oxogedunin (4), andirobin (5) and methyl angolensate (6)] were investigated for their trypanocidal and leishmanicidal activities using bloodstream forms of Trypanosoma brucei and promastigotes of Leishmania major. Whereas all compounds showed anti-trypanosomal activity, only compounds 1–4 displayed anti-leishmanial activity. The 50% growth inhibition (GI 50) values for the trypanocidal and leishmanicidal activity of the compounds ranged between 2.5 and 14.9 μM. Kotschyienone A (1) was found to be the most active compound with a minimal inhibition concentration (MIC) value of 10 μM and GI 50 values between 2.5 and 2.9 μM. Only compounds 1 and 3 showed moderate cytotoxicity against HL-60 cells with MIC and GI 50 values of 100 μM and 31.5–46.2 μM, respectively. Compound 1 was also found to show activity against intracellular amastigotes of L. major with a GI 50 value of 1.5 μM. The results suggest that limonoids have potential as drug candidates for the development of new treatments against trypanosomiasis and leishmaniasis

Título de la cubierta: V Concurso de relato corto Guinea Escribe

La V edición se ha celebrado en un marco excepcional de pandemia global, incertidumbre para el mundo de la cultura, un proceso de adaptación de los Centros, resiliencia, muchas ganas, reuniones telemáticas del jurado desde diferentes países y una presentación del libro en formato virtual con la ya mítica portada artesanal, siempre presente.Premios: Premio Literario Fundación MartínezRelatos premiados en la región continental. Primer premio: Leyenda de la dama de blanco de Reyes Irene Efua Abeng -- Segundo premio: En aquel viejo muelle de María del Pilar Oyana Nse Mangue -- Tercer premio: El joven campesino de Miguel Ngono Mba Ntongono.-- Relatos premiados en la región insular. Primer premio: En mi ausencia de Alfredo Junior Rieba Abe -- Segundo premio: Infierno de Fidel Cristóbal Nzeng Nsue Adá -- Tercer premio: Callejón sin salida de León Sidjui Tientche

Filtration de boues minérales par géotextiles

Several mining industry lead to a production of fine-grained mineral sludge, such as mature fine tailing for oil sand extraction. These sludges are hard to dewater due to their high clay content and their low hydraulic conductivity. Pressure filtration tests were conducted to filter high-clay content sludges with 8 different non-woven geotextiles (GTXs). Sludges formulated result from mixing of kaolinite and silt in order to obtain 8 different grain size distibution with D50 between 3 and 55µm and 0 to 38% of clay (DCe stage a été réalisé dans le cadre de la thèse de Sébastien Bourgès-Gastaud « utilisation des géocomposites dans les mines», le but était d’étudier l’assèchement de boues argileuses en effectuant une filtration par géotextiles en vue d’une application au traitement des résidus fins miniers. L’étude bibliographique montre que les critères usuels de dimensionnement des géotextiles pour la filtration des sols ne pouvaient s’appliquer à la filtration des boues. L’objectif étant de déterminer les paramètres importants de la filtration, des cellules de filtrations ont été développées et ont permis d’effectuer des tests de filtration selon deux variables : la granularité de la boue et le type de géotextiles. Les tests de filtration ont révélé que la filtration suit le modèle de la filtration sur support avec formation d’un gâteau de filtration. Sous une pression de 50 kPa on arrive à filtrer 50% de l’eau séquestrée par une boue argileuse ayant une siccité initiale de 40% Le taux d’assèchement de la boue ainsi que la quantité de filtrat expulsée dépendait de la granularité de la boue et de la conductivité hydraulique du gâteau. Les géotextiles n’agissent que sur la rétention des particules et la cinétique de formation du gâteau. Les géotextiles à faible ouverture de filtration et calandrés permettent d’obtenir une meilleure rétention des fines et donc un filtrat ayant une faible teneur solide

Antiplasmodial and Cytotoxic Activities of Extracts from Jacaranda mimosifolia and Pseudospondias microcarpa

International audienc

Antiplasmodial and cytotoxic activity of lanostane type triterpenoids isolated from Leplaea mayombensis

International audienceLeplaeric acid E 5, leplazarin 6a and 21-epileplazarin 6b, three new 3,4-seco-lanostane type triterpenes have been isolated from the stem bark of Leplaea mayombensis (Pellegr.) Staner along with fourteen known compounds from the fruits and roots. Leplaeric acid E, leplazarin and 21-epileplazarin, 15-α-hydroxy-3,4-seco-lanosta-4(28),8,24-triene-3,21-dioic acid, mayomlactones A and B, lanosta-7,24-dien-3-one, leplaeric acid A, B and C were screened in vitro for antiplasmodial activity against chloroquine-sensitive (Pf3D7) and chloroquine-resistant (PfINDO) strains of Plasmodium falciparum and for cytotoxicity against CAL-27, CaCo2, Skov-3, and HepG2 cells line. Three compounds including 15-α-hydroxy-3,4-seco-lanosta-4(28),8,24-triene-3,21-dioic acid (IC50 5.65–7.09 μM), lanosta-7,24-dien-3-one (IC50 7.18–9.07 μM), and leplaeric acid C (IC50 7.59–8.47 μM) were the most active against both strains of P. falciparum. All the compounds exhibited cytotoxicity against the three-cell lines with IC50 ranging from 12.30 to 181.88 μM. These results confirm the usage of the medicinal plant L. mayombensis for the management of malaria and suggest that further lead optimization studies on potent compounds identified from this study could lead to the identification of potential of lead molecules as scaffold for new antimalarial drug discovery

A NEW SOURCE OF KOJIC ACID ISOLATED FROM KIGELIA AFRICANA: A POSSIBLE PRECURSOR FOR QUINONE BIOSYNTHESIS

ABSTRACT Kojic acid (5-hydroxy-2-hydroxymethyl-γ-pyrone) a fungal metabolite produced by Aspergillus spp., Penicillium spp. and belonging mainly to the flavus-oryzaetamarii groups was isolated for the first time from Kigelia africana as the major constituent by mass fragmentation guided isolation. From a biosynthetic consideration, Kojic acid is a possible intermediate in the synthesis of the quinone scaffolds