Harnessing traditional Chinese medicine polysaccharides for combatting COVID-19.

With the global spread of COVID-19 posing ongoing challenges to public health systems, there is an ever-increasing demand for effective therapeutics that can mitigate both viral transmission and disease severity. This review surveys the landscape of polysaccharides derived from traditional Chinese medicine, acclaimed for their medicinal properties and potential to contribute to the COVID-19 response. We specifically focus on the capability of these polysaccharides to thwart SARS-CoV-2 entry into host cells, a pivotal step in the viral life cycle that informs transmission and pathogenicity. Moreover, we delve into the concept of trained immunity, an innate immune system feature that polysaccharides may potentiate, offering an avenue for a more moderated yet efficacious immune response against various pathogens, including SARS-CoV-2. Our comprehensive overview aims to bolster understanding of the possible integration of these substances within anti-COVID-19 measures, emphasizing the need for rigorous investigation into their potential applications and underlying mechanisms. The insights provided here strongly support ongoing investigations into the adjunctive use of polysaccharides in the management of COVID-19, with the anticipation that such findings could lead to a deeper appreciation and clearer elucidation of the antiviral potentials inherent in complex Chinese herbal remedies.

Inhibition of multiple SARS-CoV-2 variants entry by Lycium barbarum L. polysaccharides through disruption of spike protein-ACE2 interaction.

Viral respiratory infections are major human health concerns. The most striking epidemic disease, COVID-19 is still on going with the emergence of fast mutations and drug resistance of pathogens. A few polysaccharide macromolecules from traditional Chinese medicine (TCM) have been found to have direct anti-SARS-CoV-2 activity but the mechanism remains unclear. In this study, we evaluated the entry inhibition effect of Lycium barbarum polysaccharides (LBP) in vitro and in vivo. We found LBP effectively suppressed multiple SARS-CoV-2 variants entry and protected K18-hACE2 mice from invasion with Omicron pseudovirus (PsV). Moreover, we found LBP interfered with early entry events during infection in time-of-addition (TOA) assay and SEM observation. Further surface plasmon resonance (SPR) study revealed the dual binding of LBP with Spike protein and ACE2, which resulted in the disruption of Spike-ACE2 interaction and subsequently triggered membrane fusion. Therefore, LBP may act as broad-spectrum inhibitors of virus entry and nasal mucosal protective agent against newly emerging respiratory viruses, especially SARS-CoV-2.