Influence de l'origine des gorgones du genre Eunicella (Verril, 1869) sur la production de métabolites secondaires pharmacologiquement actifs

Abstract

The ocean covers 71% of the planet and has a biodiversity much wider than terrestrial biodiversity. However, very few pharmaceutical molecules have been isolated from this environment, yet very promising. Studies on secondary metabolites with pharmacological properties in gorgonians have been increasingly growing. Those molecules are made by a symbiosis between gorgonians and microorganisms. To extract it, some species can be overexploited in their natural environment on coral reefs. Pharmacological analyses have already been done on gorgonians of the genus Eunicella with the highlight of molecules such as terpenes and steroids, but no comparison have been made yet between different origins of those species. For this study, analyses to detect the presence of terpenes and steroids were made on the species Eunicella cavolini (Koch, 1887), Eunicella singularis (Esper, 1791) and Eunicella verrucosa (Pallas, 1766) coming from different locations: Aegean Sea, Corsica (Ligurian Sea), Roscoff (Celtic Sea) and Hendaye (Biscay Bay). Those analyses were then compared to samples coming from the culture medium in aquarium. In the natural environment, three variables were studied: depth, hydrodynamic conditions and anthropic conditions. Several techniques were used to detect the presence of secondary metabolites: thin layer chromatography, nuclear magnetic resonance spectroscopy, mass spectroscopy and Raman spectroscopy. The results highlighted the presence of terpenes and steroids in the gorgonians of the genus Eunicella. They are present in the same or even larger amount in the samples coming from the aquarium compared to the ones coming from the natural environment. Diversity and quantity is mainly influenced by the location: it’s the main characteristic coming out of this comparison. Temperature around 16°C seems to favor the development of the secondary metabolites. Between the three species studied, Eunicella verrucosa is likely to present the best results, though there are few correlations between the results of the same species. Depth, hydrodynamic conditions and anthropic conditions doesn’t seem to influence the diversity of the secondary metabolites produced. Gorgonians of the genus Eunicella are therefore marine organisms very promising for the development of pharmacological molecules in a culture environment.