Marine glycan-based antiviral agents in clinical or preclinical trials

The constant outbreak of diseases caused by viral infections has caused serious harm to human health all over the world. Although many antiviral drugs have been approved for clinical use during the past decade, important issues, such as unsatisfactory efficacy, toxicity, and high cost of drugs, remain unresolved. Glycans are major components of the surfaces of both host cells and most viruses and play critical roles in the steps of viral infection. Marine glycans have more structural diversities than those found in humans. Most importantly, low toxicity and low-cost marine glycans have demonstrated potent antiviral activities through multiple molecular mechanisms. As a result, a series of marine glycan-derived agents are undergoing preclinical and clinical trials. This review discusses the recent progress in research on the marine glycan-based antiviral agents in clinical trials, relating to their structural features and clinical applications. In addition, molecular mechanisms of marine glycans involved in viral infection and novel strategies used in glycan-based drug development are critically reviewed and discussed.