Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Sponges are a rich source for investigation of bioactive small molecules. They have been mostly investigated for the search of new pharmacological models or therapeutic agents for the treatment of human diseases. Micro-organisms can also represent a virulent pathogen for marine invertebrates such as sponges, which need to protect themselves against these microbes. Sponges' self defence mechanisms involving dialogue molecules thus represent a pertinent research track for potent anti-infective and anti-biofilm activities such as quorum sensing inhibitors (QSIs). The investigation of the QSI crude extract of Leucetta chagosensis Dendy, 1863 led to the isolation of three new alkaloids, isonaamine D, di-isonaamidine A and leucettamine D, along with the known isonaamine A and isonaamidine A. Isonaamidine A and isonaamine D were identified as inhibitors of the three quorum sensing pathways of Vibrio harveyi (CAI-1, AI-2 and harveyi auto inducer), but isonaamidine A displayed the strongest activity on AI-2 biosensor. Both compounds are new examples of natural QSIs of V. harveyi. These results outline the importance of these secondary metabolites for their producing organisms themselves in their natural environment, as well as the potential of the marine resource for aquaculture needs.
ISSN: 0266-8254

hal-01684926
https://hal.archives-ouvertes.fr/hal-01684926
DOI : 10.1111/lam.12461
PUBMED : 26138555

Éditeur(s) : HAL CCSD American Chemical Society
Résumé : International audience
A novel spiro-indolofuranone fused to a thiazine skeleton, orbicularisine (1), was isolated from gills of the mollusk Codakia orbicularis. The isolation and structure elucidation using spectroscopic evidence including mass and NMR spectroscopy are described. The final structure of 1 was supported by key HMBC correlation.
ISSN: 0163-3864

hal-01547430
http://hal.upmc.fr/hal-01547430
http://hal.upmc.fr/hal-01547430/document
http://hal.upmc.fr/hal-01547430/file/Goudou_2017_Orbicularisine.pdf
DOI : 10.1021/acs.jnatprod.7b00149

Éditeur(s) : HAL CCSD American Chemical Society
Résumé : International audience
Four bicyclic and three pentacyclic guanidine alkaloids (1–7) were isolated from a French Polynesian Monanchora n. sp. sponge, along with the known alkaloids monalidine A (8), enantiomers 9–11 of known natural product crambescins, and the known crambescidins 12–15. Structures were assigned by spectroscopic data interpretation. The relative and absolute configurations of the alkaloids were established by analysis of 1H NMR and NOESY spectra and by circular dichroism analysis. The new norcrambescidic acid (7) corresponds to interesting biosynthetic variation within the pentacyclic core. All compounds exhibited antiproliferative and cytotoxic efficacy against KB, HCT116, HL60, MRC5, and B16F10 cancer cells, with IC50 values ranging from 4 nM to 10 μM.
ISSN: 0163-3864

hal-01584556
https://hal.archives-ouvertes.fr/hal-01584556
DOI : 10.1021/acs.jnatprod.6b00168