Jellyfish blooms in the Mediterranean Sea: a potential source of functional novel food

The waste-to-resource approach promotes a paradigm shift in the management of jellyfish in coastal zones, where the sustainable exploitation of jellyfish blooms can be regarded as valuable source of benefits for a range of actors. In this framework, we studied three rhizostomeae jellyfish occurring in the Mediterranean Sea, the native Rhizostoma pulmo and Cotylorhiza tuberculata, and the non-indigenous species Cassiopea andromeda for their biomass, potentially useful as human food, and their content of bioactive compounds, with antioxidant, immunomodulatory, and anti-proliferative activities on cancer cells. R. pulmo received growing interest in western Countries where it's non-traditional food. Its organic matter, mainly composed by protein (mostly collagen), demonstrated to be valuable source of bioactive peptides. We investigated the immunomodulatory potential of R. pulmo protein hydrolysates, focusing on low-molecular weight peptide fractions, produced by enzymatic hydrolysis, and tested on U937-derived-macrophage cell cultures for inflammation-related genes expression and cytokines quantification. Our analyses showed that at non-cytotoxic concentrations, pepsin-hydrolysates significantly reduced expression of the proinflammatory cytokine genes, IL-6 and TNF?, in a dose-response. The zooxanthellatae C. tuberculata and C. andromeda are both characterized of high amount of antioxidant compounds, partly due to the presence of endosymbiotic microalgae belonging to the family Symbiodiniaceae. Partially purified hydroalcoholic extracts of both jellyfish were tested for their anti-proliferative activity and pro-apoptotic effects on human cancer cells MCF7 and MB-MDA-231. These results suggest the biomass of outbreak-forming scyphozoans may represent a yet untapped resource, with potential use in food systems, in line with the goals of the blue-green growth economy.