Fighting SARS-CoV-2 with green seaweed Ulva sp. extract: extraction protocol predetermines crude ulvan extract anti-SARS-CoV-2 inhibition properties in in vitro Vero-E6 cells assay

Shai Shefer; Arthur Robin; Alexander Chemodanov; Mario Lebendiker; Robert Bostwick; Lynn Rasmussen; Michael Lishner; Michael Gozin; Alexander Golberg

doi:10.7717/peerj.12398

Fighting SARS-CoV-2 with green seaweed Ulva sp. extract: extraction protocol predetermines crude ulvan extract anti-SARS-CoV-2 inhibition properties in in vitro Vero-E6 cells assay

PeerJ. 2021 Nov 15:9:e12398. doi: 10.7717/peerj.12398. eCollection 2021.

Authors

Affiliations

¹ Port School of Environment and Earth Sciences, Tel Aviv University, Tel Aviv, Israel.
² Silberman Institute of Life Science, Hebrew University of Jerusalem, Jeruslem, Israel.
³ Sothern Research, Birmingham, AL, United States of America.
⁴ Meir Medical Center, Kvar Sava, Israel.
⁵ School of Chemisty, Tel Aviv University, Tel Aviv, Israel.

^# Contributed equally.

Abstract

Due to the global COVID-19 pandemic, there is a need to screen for novel compounds with antiviral activity against SARS-COV-2. Here we compared chemical composition and the in vitro anti- SARS-COV-2 activity of two different Ulva sp. crude ulvan extracts: one obtained by an HCl-based and another one by ammonium oxalate-based (AOx) extraction protocols. The composition of the crude extracts was analyzed and their antiviral activity was assessed in a cytopathic effect reduction assay using Vero E6 cells. We show that the extraction protocols have a significant impact on the chemical composition, anti- SARS-COV-2 activity, and cytotoxicity of these ulvan extracts. The ulvan extract based on the AOx protocol had a higher average molecular weight, higher charge, and 11.3-fold higher antiviral activity than HCl-based extract. Our results strongly suggest that further bioassay-guided investigation into bioactivity of compounds found in Ulva sp. ulvan extracts could lead to the discovery of novel anti-SARS-CoV-2 antivirals.

Keywords: Antiviral; Extraction; Macroalgae; SARS-CoV-2; Seaweed; Sulfated polysaccharides; Ulva sp.; Ulvan.

Grants and funding

This work was supported by Porter Family Fund. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.