Harnessing the ocean’s chemistry: ecological functions and therapeutic potential of phlorotannins
TL;DR
This review critically evaluates current knowledge on the ecological functions, bioavailability, pharmacokinetics, and safety profiles of phlorotannins across diverse biological models, including cell cultures, invertebrates, rodents, and limited human studies, while identifying key challenges that hinder clinical translation.
Abstract
Phlorotannins are unique polyphenolic compounds produced exclusively by brown algae, functioning as adaptive marine metabolites that mediate ecological defence, environmental stress responses, and species-specific biological functions. Their biosynthesis is regulated by ecological pressures such as UV radiation, herbivory, and oxidative stress, linking marine adaptation with biomedical relevance. This review critically evaluates current knowledge on the ecological functions, bioavailability, pharmacokinetics, and safety profiles of phlorotannins across diverse biological models, including cell cultures, invertebrates, rodents, and limited human studies, while identifying key challenges that hinder clinical translation. Accumulating evidence indicates that phlorotannins generally exhibit low toxicity toward normal cells and selective cytotoxicity against cancer cells; however, comprehensive long-term safety assessments remain lacking. Their therapeutic efficacy is further constrained by poor bioavailability, which is influenced by molecular weight, gastrointestinal stability, gut microbiota-mediated metabolism, and first-pass hepatic metabolism. Emerging strategies, including nanoencapsulation, liposomal delivery systems, and advanced extraction technologies, offer promising solutions to enhance pharmacokinetic performance and bioactivity. As evolutionarily conserved marine bioactive compounds, phlorotannins represent an important interface between marine ecology and biomedical science, with significant potential as sustainable therapeutic candidates. Future research should integrate optimized extraction methods, advanced nanoformulations, and multi-omics approaches to elucidate molecular mechanisms, improve bioavailability, and accelerate clinical translation. Sustainable aquaculture and responsible harvesting practices will be essential to ensure a reliable supply of phlorotannins while preserving marine ecosystem integrity.