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.
Keywords: COVID-19; Caulerpa lentillifera; SARA-CoV-2; Sulfated polysaccharide.
Copyright © 2021. Published by Elsevier Ltd.