title: Quorum sensing inhibitors from Leucetta chagosensis Dendy, 1863.
abstract: 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.
  
  
  CONCLUSIONS
  A new type of quorum sensing inhibitors was isolated from the sponge Leucetta chagosensis. One of them inhibits strongly the AI-2 channel of Vibrio harveyi, a marine pathogen of special importance in aquaculture. The activity of five different related compounds, including three new natural products discovered there, was investigated leading to structure-activity relationships which are useful for the design of new quorum sensing inhibitors to control marine infectious pathogens.
authors.affiliation: IRD, UMR241-EIO, Papeete, Tahiti, French Polynesia.|Centre de Recherche de Gif-sur-Yvette, Institut de Chimie des Substances Naturelles, CNRS, Gif-sur-Yvette Cedex, France.
authors.forename: T
authors.initials: T
authors.lastname: Mai
authors.affiliation: IRD, UMR241-EIO, Papeete, Tahiti, French Polynesia.
authors.forename: F
authors.initials: F
authors.lastname: Tintillier
authors.affiliation: IFREMER, UMR241-EIO, LABEX CORAIL, Taravao, Tahiti, French Polynesia.
authors.forename: A
authors.initials: A
authors.lastname: Lucasson
authors.affiliation: Centre de Recherche de Gif-sur-Yvette, Institut de Chimie des Substances Naturelles, CNRS, Gif-sur-Yvette Cedex, France.
authors.forename: C
authors.initials: C
authors.lastname: Moriou
authors.affiliation: IRD, UMR241-EIO, Papeete, Tahiti, French Polynesia.
authors.forename: E
authors.initials: E
authors.lastname: Bonno
authors.affiliation: IRD, UMR241-EIO, Papeete, Tahiti, French Polynesia.
authors.forename: S
authors.initials: S
authors.lastname: Petek
authors.affiliation: IFREMER, UMR241-EIO, LABEX CORAIL, Taravao, Tahiti, French Polynesia.
authors.forename: K
authors.initials: K
authors.lastname: Magré
authors.affiliation: Centre de Recherche de Gif-sur-Yvette, Institut de Chimie des Substances Naturelles, CNRS, Gif-sur-Yvette Cedex, France.
authors.forename: A
authors.initials: A
authors.lastname: Al Mourabit
authors.affiliation: IFREMER, UMR241-EIO, LABEX CORAIL, Taravao, Tahiti, French Polynesia.
authors.forename: D
authors.initials: D
authors.lastname: Saulnier
authors.affiliation: IRD, UMR241-EIO, Papeete, Tahiti, French Polynesia.
authors.forename: C
authors.initials: C
authors.lastname: Debitus
mesh_terms: D000470:Alkaloids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D017756:Aquaculture; D018441:Biofilms / Q000187:drug effects*; D057219:Biofouling / Q000517:prevention & control*; D007093:Imidazoles / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D011161:Porifera / Q000737:chemistry*; D053038:Quorum Sensing / Q000187:drug effects*; D013329:Structure-Activity Relationship; D014733:Vibrio / Q000187:drug effects / Q000502:physiology
chemical_list: D000470:Alkaloids; D007093:Imidazoles
keywords: Leucetta chagosensis; Vibrio harveyi; biofouling; leucettamine; naamidine; naamine; quorum sensing; quorum sensing inhibitors; sponges