Griffithsin and carrageenan combination results in antiviral synergy against sars-cov-1 and 2 in a pseudoviral model

Sahar Alsaidi, Nadjet Cornejal, Oneil Mahoney, Claudia Melo, Neeharika Verma, Thierry Bonnaire, Theresa Chang, Barry R. O’keefe, James Sailer, Thomas M. Zydowsky, Natalia Teleshova, José A. Fernández Romero

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Over 182 million confirmed cases of COVID-19 and more than 4 million deaths have been reported to date around the world. It is essential to identify broad-spectrum antiviral agents that may prevent or treat infections by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) but also by other coronaviruses that may jump the species barrier in the future. We evaluated the antiviral selectivity of griffithsin and sulfated and non-sulfated polysaccharides against SARS-CoV-1 and SARS-CoV-2 using a cytotoxicity assay and a cell-based pseudoviral model. The half-maximal cytotoxic concentration (CC50 ) and half-maximal effective concentration (EC50 ) were determined for each compound, using a dose-response-inhibition analysis on GraphPad Prism v9.0.2 software (San Diego, CA, USA). The therapeutic index (TI = CC50/EC50 ) was calculated for each compound. The potential synergistic, additive, or antagonistic effect of different compound combinations was determined by CalcuSyn v1 software (Biosoft, Cambridge, UK), which estimated the combination index (CI) values. Iota and lambda carrageenan showed the most potent antiviral activity (EC50 between 3.2 and 7.5 µg/mL). Carrageenan and griffithsin combinations exhibited synergistic activity (EC50 between 0.2 and 3.8 µg/mL; combination index <1), including against recent SARS-CoV-2 mutations. The griffithsin and carrageenan combination is a promising candidate to prevent or treat infections by SARS-CoV-1 and SARS-CoV-2.

Original languageEnglish (US)
Article number418
JournalMarine Drugs
Issue number8
StatePublished - Aug 2021

All Science Journal Classification (ASJC) codes

  • Drug Discovery
  • Pharmacology, Toxicology and Pharmaceutics (miscellaneous)
  • Pharmaceutical Science


  • Lectins
  • SARS-CoV-1
  • SARS-CoV-2
  • Sulfated polysaccharides


Dive into the research topics of 'Griffithsin and carrageenan combination results in antiviral synergy against sars-cov-1 and 2 in a pseudoviral model'. Together they form a unique fingerprint.

Cite this