Evaluating the potential of bioactive metabolites in red seaweed extracts : addressing key challenges through integration and innovation of cell assays

Food security is one of the biggest challenges in the 21st century. As the focus of food requirements shifts towards enhancing human health and preventing disease. Seaweed has garnered significant attention as a natural source of bioactive compounds but also as a source of environmental contaminants when cultured in or harvested from the field. However, current research provides little insight into the effects of entire seaweed extracts which contain complex mixtures of bioactive ingredients with potential environmental pollutants, nor do we fully understand the molecular mechanisms through which they act in human cells. This knowledge gap limits our ability to assess the true potential of seaweed and consequences of increased environmental pollution. Therefore, we explored the use of novel approach methodologies to evaluate the impact of both purified compounds derived from red seaweed on human cell lines, while also examining whole seaweed extracts for a comprehensive analysis. The red pigment R-phycoerythrin (R-PE) and the carbohydrate floridoside were evaluated, while aquatic seaweed extracts (in PBS solution) from three red algal species, i.e. Porphyra umbilicalis, Acrochaetium secundatum and Gracilaria gracilis were explored. Cytotoxic, antioxidant, and metabolic properties, as early biomarkers of adversity, were evaluated towards two human cell lines: colon adenocarcinoma Caco-2 cells and the acute monocytic leukemia cell line THP-1. Cell viability, metabolic, cytokine and ROS measurements were performed on THP-1 and Caco-2 after exposure to the different treatments. As such, the integration of these data will allow us to improve our understanding of the specific roles of the molecules of interest in the corresponding extracts, which will be crucial for AOP development. Through this research, we aim to advance both the aquaculture as food safety fields by establishing quantitative links between molecular markers and the chemical composition of seaweed.