Bioactive compounds from native and non-native Mediterranean jellyfish

The biotechnological potential of gelatinous zooplankton, as cnidarians, has begun to attract the attention of researchers since the discovery of the GFP protein and their well-documented ability to produce venom. However, further studies have shown that the biochemical diversity of cnidarians produces several other classes of bioactive compounds also as a result of their complex symbiotic biology. The increase in the number of scyphozoan jellyfish blooms, individuals and duration of jellyfish outbreaks in the Mediterranean Sea, as well as the increase in the presence of non-native species, have prompted studies on their biology and composition that have contributed to a better understanding of these organisms. Bioprospection, as an interdisciplinary area including pharmaceutical and marine biology disciplines, explores the biodiversity of jellyfish, their bioactive compounds, chemical classes and modes of action. Results about scyphozoan jellyfish occurring in the Mediterranean Sea, such as the native Rhizostoma pulmo and Cotylorhiza tuberculata, and the non-native species Cassiopea andromeda and Aurelia coerulea are presented. Compositional analysis of jellyfish biomass and their content of bioactive compounds, with antioxidant, immunomodulatory, and antiproliferative activities on human cell cultures demonstrate their potential usefulness as nutraceuticals or pharmaceuticals. Structural proteins, including collagen, produce antioxidant and anti-inflammatory peptides by hydrolysis, while zooxanthellate jellyfish such as C. tuberculata and C. andromeda holobionts, represent a source of potent antioxidant and cancer-preventive compounds originating mainly from endosymbiotic zooxanthellae. Jellyfish-related bioprospecting sources are also vital for the stability of marine food webs. Furthermore, the complex relationships between marine life and climate should be thoroughly understood for sustainable bioprospecting and conservation of valuable marine resources. Bioprospecting strategies should therefore also be an opportunity to study marine biodiversity and expand the dialogue on sustainability in marine resource exploitation.