Jean-Louis Pousset

Isocryptolepine from Cryptolepis sanguinolenta

A new alkaloid, 5-methyl, 5H-indolo-[3,2-c]-quinoline named isocryptolepine, has been isolated from the roots of Cryptolepis sanguinolenta and its structure determined from spectroscopic data, including IR, MS and NMR.

Antimalarial Activity of Cryptolepine and Isocryptolepine, Alkaloids Isolated from Cryptolepis sanguinolenta

Cryptolepis sanguinolenta extracts are currently used by African herbalists to cure malaria but the compounds involved in its antimalarial activity have not been identified. Two alkaloids, cryptolepine and isocryptolepine, have been isolated from the roots of C. sanguinolenta and their antimalarial activity evaluated. Both alkaloids possess intrinsic inhibitory activity against the human malaria parasite, Plasmodium falciparum in vitro, whatever the chloroquine‐resistance status of the strains used. Cryptolepine was slightly more efficient for parasite killing with an IC50 in the range of 0.2 to 0.6u2009μMSC compared with an IC50 of about 0.8u2009μMSC for isocryptolepine. The antimalarial activity of cryptolepine was confirmed in vivo on the rodent malarial parasites Plasmodium vinckei petteri and Plasmodium berghei ANKA.

Curcacycline B, a cyclic nonapeptide from Jatropha curcas enhancing rotamase activity of cyclophilin

The structure of curcacycline B (1), a cyclic nonapeptide isolated from Jatropha curcas latex was elucidated by combination of chemical degradation, LSIMS data and 2D NMR experiments. Curcacycline B was shown to enhance the rotamase activity of human cyclophilin B.

Pohlianins A, B and C, cyclic peptides from the laxes of Jatropha pohliana ssp. molissima

Abstract From the EtOAc extract of the latex of Jatropha pohliana (Euphorbiaceae), two cyclic heptapeptides, pohlianins A (1) and B (2) and one cyclic octapeptide, pohlianin C (3) were isolated by a multi-step chromatography procedure, including HPLC. Their structure were elucidated by chemical degradation, mass spectrometry, homonuclear and heteronuclear NMR experiments. Conformational analysis of these peptides was made by using NMR experiments and distance geometry calculations. Their antimalarial activities were examined.

Mahafacyclin A, a cyclic heptapeptide from Jatropha mahafalensis exhibiting β-bulge conformation

Abstract The structure of mahafacyclin A ( 1 ), a cyclic heptapeptide isolated from Jatropha mahafalensis latex was elucidated by a combination of chemical degradation, LSIMS data and 2D NMR experiments. Mahafacyclin A solution conformation was shown to have β-bulge characteristics.

Isolation, structure and synthesis of mahafacyclin B, a cyclic heptapeptide from the latex of Jatropha mahafalensis

Mahafacyclin B is a cyclic heptapeptide with antimalarial activity isolated from the latex of Jatropha mahafalensis. The structure is elucidated by chemical degradation, tandem mass spectrometry, homo- and heteronuclear NMR experiments, and confirmed by synthesis.

1,3-di-O-galloylquinic acid from Guiera senegalensis

A new polyphenol, 1,3-di-O-galloylquinic acid, and the known quinic acid gallates, 3-O-, 4-O-, 5-O-, 3,4-di-O-, 4,5-di-O-, 3,5-di-O-, 3,4,5-tri-O- and 1,3,4,5-tetra-O-galloylquinic acids were isolated from the galls of Guiera senegalensis.

Isolation, structure and synthesis of chevalierins A, B and C, cyclic peptides from the latex of Jatropha chevalieri

From the EtOAc extract of the latex of Jatropha chevalieri (Euphorbiaceae), two cyclooctapeptides, chevalierins A (1) and B (2), and a cyclononapeptide, chevalierin C (3), were isolated by a multi-step chromatography procedure, including HPLC. Their structures were elucidated by chemical degradation, mass spectrometry, homonuclear and heteronuclear NMR experiments and confirmed from their synthesis. Their antimalarial activities were examined.

Isolation and structure of cyclosenegalins A and B, novel cyclopeptides from the seeds of Annona senegalensis

Two new cyclopeptides, cyclosenegalin A, cyclo(Pro1-Gly2-Leu3-Ser4-Ala5-Val6-Thr7-) n(1) and cyclosenegalin B, cyclo(Pro1-Gly2-Tyr3-Val4-Tyr5-Pro6-Pro7-Val8-) n(2), have been isolated from the methanol extract of the seeds of Annona senegalensis Pers., along with the known cyclic peptide, glabrin A. The structures were elucidated on the basis of the MS/MS fragmentation, using a Q-TOF mass spectrometer equipped with an ESI source, chemical degradation and extensive 2D-NMR.