Bioactive Secondary Metabolites at the Ends of the Earth (2015–2025): Insights into Arctic and Antarctic Aquatic Sources

Marine organisms living in extreme environments such as the Arctic and Antarctic have evolved remarkable adaptation mechanisms to survive harsh conditions, including low temperatures, high salinity, and seasonal fluctuations in light and nutrients. Among these adaptations, unique biochemical pathways have given rise to secondary metabolites with unprecedented chemical structures and diverse biological activities. This review focuses on bioactive natural products that have been isolated from polar aquatic organisms between 2015 and 2025. It provides a comprehensive overview of these compounds, highlighting their chemical structures, source organisms, and documented biological activities. By examining recent discoveries from the ends of the Earth, this review underscores the rich chemical diversity of polar marine ecosystems and their continued potential as a source of novel molecules for drug discovery and biotechnology.