Antiplasmodial Activities of Homogentisic Acid Derivative Protein Kinase Inhibitors Isolated from a Vanuatu Marine Sponge Pseudoceratina sp.

As part of our search for new antimalarial drugs in South Pacific marine sponges, we have looked for inhibitors of Pfnek-1, a specific protein kinase of Plasmodium falciparum. On the basis of promising activity in a preliminary screening, the ethanolic crude extract of a new species of Pseudoceratina collected in Vanuatu was selected for further investigation. A bioassay-guided fractionation led to the isolation of a derivative of homogentisic acid [methyl (2,4-dibromo-3,6-dihydroxyphenyl)acetate, 4a] which inhibited Pfnek-1 with an IC50 around 1.8 μM. This product was moderately active in vitro against a FcB1 P. falciparum strain (IC50 = 12 μM). From the same sponge, we isolated three known compounds [11,19-dideoxyfistularin-3 (1), 11-deoxyfistularin-3 (2) and dibromo-verongiaquinol (3)] which were inactive against Pfnek-1. Synthesis and biological evaluation of some derivatives of 4a are reported

Update 1 of: Macrolactonizations in the Total Synthesis of Natural Products

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Routine use of natural abundance deuterium NMR in a polypeptidic chiral oriented solvent for the determination of the enantiomeric composition of chiral building blocks

International audienceNatural abundance deuterium 2D NMR spectroscopy in chiral liquid crystal was successfully used to efficiently analyze the enantiomeric composition of organic chiral building blocks involved in the syntheses of natural and synthetic bioactive products. The results reported here emphasize the high potential of this analytical strategy and prove its applicability for routinely determining enantiomeric excesses

Triboelectrostatic separation of brominated flame retardants polymers from mixed granular wastes

International audienceThe general purpose of the present paper is to study the feasibility of removing brominated flame retardants (BFR) polymers from mixed granular wastes using tribo-electrostatic separation. The study was carried out on mixtures consisting in equal quantities of high impact polystyrene (HIPS) particles either BFR-free or containing 40000 ppm of brome (4.7%). Three triboelectric charging devices were used: a vibrating tribocharger (a container made of stainless steel, polystyrene or polypropylene and fixed on a vibrating table); a rotating cylinder tribocharger made of polyvinyl chloride; a fluidized bed tribocharger, the walls of which were made of poly methyl methacrylate. The selective sorting of the granular mixture was performed using a roll type electrostatic separator. The results confirm that separating BFR HIPS from BFR-free HIPS is feasible. Best separation results were obtained for the mixture tribocharged in the fluidized bed tribocharger