Structural characterization and SARS-CoV-2 inhibitory activity of a sulfated polysaccharide from Caulerpa
Ying You1, Haoran Song2, Lilong Wang2
1College of Food Science and Engineering, Jilin Agricultural University, Changchun, PR China; National & Local Joint Engineering Laboratory for Marine Bioactive Polysaccharide Development and Application, Dalian Polytechnic University, Dalian 116034, PR China.
Abstract:
Caulerpa lentillifera (Bryopsidophyceae, Chlorophyta) is an edible seaweed attracting great attention for its expansion of farming scale and increasing consumption in these years. In the present study, a sulfated polysaccharide (CLSP-2) was isolated and separated from C. lentillifera, and its chemical structure was elucidated by a series of chemical and spectroscopic methods. Among these methods, mild acid hydrolysis and photocatalytic degradation were applied to release mono- and oligo-saccharide fragments which were further identified by HPLC-MSn analysis, affording the information of the sugar sequences and the sulfate substitution in CLSP-2. Results indicated that the backbone of CLSP-2 was constructed of →6)-β-Manp-(1→ with sulfated branches at C2, which were comprised of prevalent →3)-β-Galp4S-(1→, →3)-β-Galp2,4S-(1→, and minor Xyl. In addition, the virus neutralization assay revealed that CLSP-2 could effectively protect HeLa cells against SARS-CoV-2 infection with an IC50 of 48.48 μg/mL. Hence, the present study suggests CLSP-2 as a promising agent against SARS-CoV-2.
