Isolation, structural characterization, and antiviral activity of a sulfated polysaccharide (LJP-1) from Laminaria...

Herpes simplex virus type 1 (HSV-1) represents a widespread and prevalent human pathogen that leads to various conditions, including herpes labialis, herpes keratitis, and neonatal encephalitis. In this study, sulfated polysaccharide (LJP-1) with a molecular weight of 272,231 Da was isolated from Laminaria japonica, a species of brown algae recognized for its medicinal and nutritional properties. The monosaccharide composition, FT-IR, methylation, GC-MS, and NMR analysis revealed that the backbone structure of LJP-1 was composed of 1,4-α-D-GlcpA, 1,6-β-D-Galp, and 1,4,6-β-D-Galp. The sulfate groups were located at the C-4 position of T-β-D-Xylp unit. Besides, the antiviral efficacy of LJP-1 against HSV-1 was evaluated using Vero cells in vitro and a mouse model of skin zosteriform infection in vivo. Our findings revealed that LJP-1 exhibited significant inhibitory effects on HSV-1 attachment, penetration, and viral particle activation. Moreover, LJP-1 alleviated the symptoms associated with skin disorders induced by HSV-1 and inhibited the replication of HSV-1 by reducing the expression levels of ICP27 and gB. Furthermore, the viral titer of HSV-1 was significantly decreased in the skin tissues of infected mice. Collectively, these results indicate that LJP-1 has huge potential as an anti-HSV-1 agent for applications in the functional food and pharmaceutical industries.