PLoS ONE (Jan 2021)

Iota-carrageenan neutralizes SARS-CoV-2 and inhibits viral replication in vitro.

  • Martina Morokutti-Kurz,
  • Maria Fröba,
  • Philipp Graf,
  • Maximilian Große,
  • Andreas Grassauer,
  • Janina Auth,
  • Ulrich Schubert,
  • Eva Prieschl-Grassauer

DOI
https://doi.org/10.1371/journal.pone.0237480
Journal volume & issue
Vol. 16, no. 2
p. e0237480

Abstract

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In the absence of a vaccine and other effective prophylactic or therapeutic countermeasures the severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) remains a significant public health threat. Attachment and entry of coronaviruses including SARS-CoV-2 is mainly mediated by the spike glycoprotein. Here, we show that iota-carrageenan can inhibit the cell entry of the SARS-CoV-2 spike pseudotyped lentivirus in a dose dependent manner. SARS-CoV-2 spike pseudotyped lentivirus particles were efficiently neutralized with an IC50 value of 2.6 μg/ml iota-carrageenan. Experiments with patient isolated wild type SARS-CoV-2 virus showed an inhibition of replication in a similar range. In vitro data on iota-carrageenan against various Rhino- and endemic Coronaviruses showed similar IC50 values and translated readily into clinical effectiveness when a nasal spray containing iota-carrageenan demonstrated a reduction of severity and duration of symptoms of common cold caused by various respiratory viruses. Accordingly, our in vitro data on SARS-CoV-2 spike pseudotyped lentivirus and replication competent SARS-CoV-2 suggest that administration of iota-carrageenan may be an effective and safe prophylaxis or treatment for SARS-CoV-2 infections.