No abstract

An in vitro screening of New Caledonian plants allowed the selection of several species with a significant dengue virus NS5 RNA-dependent RNA polymerase (RdRp) inhibiting activity. The chemical investigation of Cryptocarya chartacea led to the isolation of a series of new mono-and dialkylated flavanones named chartaceones A−F (1−6), along with pinocembrin. They were isolated as racemic mixtures and characterized using extensive one-and two-dimensional NMR spectroscopy. Four diastereomers of chartaceone A (1) were separated using chiral HPLC, and their absolute configurations were established by comparison of their experimental and calculated ECD spectra. The dialkylated flavanones, chartaceones C−F (3−6), exhibited the most significant NS5 RdRp inhibiting activity, with IC 50 ranging from 1.8 to 4.2 μM. Chartaceones represent a new class of non-nucleosidic inhibitors of the DENV NS5 RdRp.

We report the elaboration of novel bio-sourced ecocatalysts for Ullmann coupling reaction. Ecocatalysis is based on the recycling of metals issued from phytoremediation or rehabilitation, and an innovative chemical valorization of the subsequent biomass in the field of catalysis. Here, we describe the efficient copper accumulation by plants via phytoextraction and rhizofiltration. These phytotechnologies were revisited to demonstrate a novel potential of these natural resources for the Green Chemistry. Taking advantage of the remarkable ability of the selected plants to accumulate Cu(II) species into their roots or leaves, these latter can be directly used for the preparation of ecocatalysts, called Eco-Cu ® . The formed Eco-Cu ® catalysts are thoroughly characterized via ICP-MS, IR study of pyridine sorption/desorption, TEM, XRD, SM and model reactions, in order to elucidate the chemical composition and catalytic activity of these new materials. Significant differences of properties and activities were observed between Eco-Cu ® and conventional Cu catalysts. Eco-Cu ® appear as highly active catalysts in Ullmann coupling reactions with lower Cu quantity compared to known copper catalysts.