Hélène Guinaudeau

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As part of an ongoing collaborative effort to discover new antimalarial agents from natural sources, we have tested 53 bisbenzylisoquinoline alkaloids for cytotoxicity against cultured mammalian cells and for antiplasmodial activity against chloroquine-sensitive and chloroquine-resistant clones of Plasmodium falciparum. The isolates from Cyclea barbata,(More)
Methods using liquid chromatography with UV detection (LC-UV), thin-layer chromatography (TLC), and digital photomicroscopy were developed to distinguish between the different species of Scutellaria lateriflora L. and its adulterants Teucrium canadense L. and T. chamaedrys L. Chemically, the 70% ethanol extract of S. lateriflora is characterized by the(More)
Eleven bisbenzylisoquinoline (BBIQ) alkaloids were studied for in vitro trypanocidal activity against trypomastigote forms of the Y strain of Trypanosoma cruzi. The inhibitory activity of these compounds against trypanothione reductase (TR), a target enzyme for chemotherapy against Chagas disease, was also studied. Six BBIQ alkaloids (antioquine,(More)
Thirteen known isoquinoline alkaloids were isolated from Ocotea lancifolia, popularly known as << canela pilosa >> in Brasil and << laurel né >> by the Guarani people which means smell laurel. Their activities against the promastigote forms of three Leishmania strains and the bloodstream form of Trypanosoma cruzi were evaluated, as well as their(More)
Continuing studies of the alkaloidal fraction from the roots of Cyclea barbata afforded two new bisbenzylisoquinoline alkaloids, namely, (-)-2'-norlimacine [1] and (+)-cycleabarbatine [2]. The known (+)-tetrandrine-2'-beta-N-oxide [3], for which the configuration of the N-oxide function is now assigned, was identified, as were (+)-berbamine, (-)-repandine,(More)
A MeOH extract of Nectandra salicifolia trunk bark, obtained during a diversity-based plant collection in a lower montane rainforest in Costa Rica, showed activity in an in vitro antiplasmodial assay measuring incorporation of [3H]-labeled hypoxanthie by Plasmodium falciparum. In addition to 15 known alkaloids isolated from samples of trunk bark, roots, and(More)