Insights into prospective antiviral activities of algal polysaccharides along with their properties, extraction, and characterization: A review.

The global escalation of viral outbreaks, particularly the COVID-19 pandemic caused by SARS-CoV-2, highlights the urgent need for effective antiviral agents against emerging infections. Despite their importance, quarantine and vaccination alone are insufficient, necessitating advanced approaches for effective viral infection control. One such strategy involves investigating efficacious antiviral agents that don't induce toxicity. Algal polysaccharides represent a significant frontier in pharmacological research for the development of novel antiviral therapeutics. Unlike other sources, marine algae offer an underexploited reservoir of unique metabolites with potent, broad-spectrum antiviral properties. A multitude of studies have recognized numerous algal polysaccharides exhibiting antiviral characteristics, including laminaran, alginate, carrageenan, fucan, and naviculan. Moreover, these polysaccharides exert antiviral effects through diverse mechanisms, including blocking viral attachment and entry into host cells, as well as inhibiting viral genome replication and protein synthesis. The shift towards treatment with polysaccharides derived from marine algae represents a step towards more flexible and resistance-resistant antiviral strategies. By leveraging the gradual evolution of algal metabolites, researchers can develop agents that are not only effective against current threats but also adaptable to changes in the antigenic composition of future viral outbreaks. This review summarizes recent advances in the current understanding of algal polysaccharides, including their production, extraction methods, structural characterization, and applications in gene delivery. It also provides a critical discussion of structure-activity relationships, antiviral mechanisms, and comparative evaluation of different classes of algal polysaccharides to support their advancement as promising natural antiviral agents for future research and therapeutic development.