109 | Novel eco-sustainable approaches to prevent and mitigate emerging contaminants-induced physiological changes in a marine model organisms

Cristiana Roberta Multisanti¹, Marina Russo², Paolo Pastorino³, Giuseppe Piccione¹, Federica Impellitteri¹, Caterina Faggio^4|5 | ¹Dept of Veterinary Sciences, University of Messina, Messina, Italy; ²Dept of Chemical, Biological, Pharmaceutical, and Environmental Sciences, Messina Institute of Technology c/o, University of Messina, Messina, Italy; ³Zooprophylactic Institute of Piedmont, Liguria and Valle d'Aosta, Turin, Italy; ⁴Dept of Chemical, Biological, Pharmaceutical, and Environmental Sciences, University of Messina, Messina, Italy; ⁵Dept of Eco-sustainable Marine Biotechnology, SZN Anton Dohrn, Naples, Italy.

Nature-based compounds are increasingly investigated as eco-friendly tools to mitigate pollutant-induced toxicity in aquatic organisms, due to their richness in bioactive molecules (e.g., polyphenols, flavonoids, and other antioxidants) able to support cellular stress, immune competence, organisms’ resilience and homeostasis (1). Beyond their biological potential, these approaches also fit a circular bioeconomy perspective, as they enable the valorisation of olive oil industry residues. Indeed, converting these low-value side streams into high-value extracts may reduce waste and promote sustainable innovation. Within this framework, the present investigation aimed to obtain novel insights into the potential protective and mitigatory role of the olive leaf extract (OLE), obtained from olive oil industry residual biomass, on the cellular and physiological performances of Mytilus galloprovincialis exposed to the neonicotinoid insecticide thiacloprid (THI), which is already recognised as a contaminant capable of compromising the health of organisms (2). Bioactive molecules were obtained by solvent extraction of olive-derived residues, and the extract was then subjected to characterisation. Specimens were exposed to THI (4.5 μg/L), OLE (5 mg/L), and their mixture (THI+OLE), for fourteen days. Endpoints addressed immune competence, e.g., haemocyte functional activity and cytoskeleton-related signalling; cellular functionality and vitality, e.g., lysosomal stability and membrane integrity in haemocytes and digestive gland (DG) cells; redox balance through selected molecular biomarkers linked to antioxidant defences and cellular protection; cell osmoregulatory capacity through the evaluation the ability of DG cells to cope with osmotic challenge and restore cell volume. Results showed a consistent pattern across all analyses. No significant differences were observed between the control and OLE groups, whereas significant changes emerged in the THI-treated groups. Notably, co-exposure (THI+OLE) was associated with a recovery toward control-like levels. Overall, these findings support and provide novel insights into the potential of olive leaf-derived bioactive compounds to mitigate contaminant-induced toxicity, while highlighting the bioeconomic value of upgrading olive oil processing residues into functional extracts for environmentally sustainable applications in aquatic toxicology. In a broader “One Health” perspective, improving the resilience of marine bivalves contributes not only to ecosystem integrity but also to human well-being, considering the high commercial value of Mytilus galloprovincialis as a widely farmed and consumed seafood species and its central role in coastal economies and food supply chains.