Antiviral properties
Seaweed has been reported important source of antiviral agents with high efficacy on resistant mutant viral strains and low toxicity to host (120, 121). Water soluble extracts from seaweeds demonstrated antiviral activity against a wide range of viruses (122). Among the bioactive molecule from seaweeds with antiviral activity are polysaccharides from marine organism which can either inhibit the replication of the virus by interfering with the viral life cycle or improve the host antiviral immune responses to accelerate the process of viral clearance (123). The life cycle of viruses differs greatly between species, but there are six basic stages in the life cycle of viruses; viral adsorption, viral penetration, uncoating of capsids, biosynthesis, viral assembly, and viral release (124). Therefore, Marine polysaccharides can inhibit viral life cycle at different stages or directly inactivate virions before virus infection.