Triterpenoids in Echinoderms: Fundamental Differences in Diversity and Biosynthetic Pathways
Emily J. S. Claereboudt,
Guillaume Caulier,
Corentin Decroo,
Emmanuel Colson,
Pascal Gerbaux,
Michel R. Claereboudt,
Hubert Schaller,
Patrick Flammang,
Magali Deleu,
Igor Eeckhaut
Affiliations
Emily J. S. Claereboudt
Biology of Marine Organisms and Biomimetics Unit, Research Institute for Biosciences, University of Mons-UMONS, 7000 Mons, Belgium
Guillaume Caulier
Biology of Marine Organisms and Biomimetics Unit, Research Institute for Biosciences, University of Mons-UMONS, 7000 Mons, Belgium
Corentin Decroo
Biology of Marine Organisms and Biomimetics Unit, Research Institute for Biosciences, University of Mons-UMONS, 7000 Mons, Belgium
Emmanuel Colson
Biology of Marine Organisms and Biomimetics Unit, Research Institute for Biosciences, University of Mons-UMONS, 7000 Mons, Belgium
Pascal Gerbaux
Organic Synthesis and Mass Spectrometry Laboratory, Interdisciplinary Center for Mass Spectrometry, Research Institute for Biosciences, University of Mons—UMONS, 7000 Mons, Belgium
Michel R. Claereboudt
Department of Marine Science and Fisheries, College of Agricultural and Marine Sciences, Sultan Qaboos University, 123 Al-Khod, Oman
Hubert Schaller
Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, 67084 Strasbourg Cedex, France
Patrick Flammang
Biology of Marine Organisms and Biomimetics Unit, Research Institute for Biosciences, University of Mons-UMONS, 7000 Mons, Belgium
Magali Deleu
Laboratory of molecular biophysics of interfaces, Gembloux Agro-Bio Tech, University of Liege, 5030 Gembloux, Belgium
Igor Eeckhaut
Biology of Marine Organisms and Biomimetics Unit, Research Institute for Biosciences, University of Mons-UMONS, 7000 Mons, Belgium
Echinoderms form a remarkable phylum of marine invertebrates that present specific chemical signatures unique in the animal kingdom. It is particularly the case for essential triterpenoids that evolved separately in each of the five echinoderm classes. Indeed, while most animals have Δ5-sterols, sea cucumbers (Holothuroidea) and sea stars (Asteroidea) also possess Δ7 and Δ9(11)-sterols, a characteristic not shared with brittle stars (Ophiuroidea), sea urchins (Echinoidea), and crinoids (Crinoidea). These particular Δ7 and Δ9(11) sterols emerged as a self-protection against membranolytic saponins that only sea cucumbers and sea stars produce as a defense mechanism. The diversity of saponins is large; several hundred molecules have been described in the two classes of these saponins (i.e., triterpenoid or steroid saponins). This review aims to highlight the diversity of triterpenoids in echinoderms by focusing on sterols and triterpenoid glycosides, but more importantly to provide an updated view of the biosynthesis of these molecules in echinoderms.
