Iota-Carrageenan Prevents the Replication of SARS-CoV-2 in a Human Respiratory Epithelium Cell Line in vitro

Abstract

Iota-carrageenan is a sulfated polysaccharide extracted from red seaweeds, which, formulated into a nasal spray, has already been proven safe and effective in viral upper respiratory infections. In Calu-3, a human respiratory epithelium cell line, we explored the activity of a formula of iota-carrageenan and sodium chloride against SARS-CoV-2. In this study, the assayed formula, already approved as a nasal spray for human use, effectively inhibited SARS-CoV-2 infection, providing a more substantial reference for clinical studies or developments.

Evaluation of Antiviral Effect against SARS-CoV-2 Propagation by Crude Polysaccharides from Seaweed and Abalone Viscera In Vitro

“…A number of marine polysaccharides, comprised of carrageenan, laminarin, alginate, fucoidan, chitosan, ulvan, agar, and porphyran, have exhibited directly and indirectly antiviral effects against SARS-CoV-2 [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. Iota-carrageenan inhibits the replication of SARS-CoV-2 and its variants alpha, beta, gamma, and delta [ 9 ], and lambda-carrageenan also has demonstrated antiviral activity against influenza virus and SARS-CoV-2 [ 7 , 8 ]. Sulfated polysaccharides effectively inhibited SARS-CoV-2 entry by interfering with the interaction of the spike protein with the ACE2 receptor of the host cell in vitro [ 13 , 14 , 15 , 16 ].…”

“…It is presumed that crude polysaccharides from seaweed and abalone viscera inhibit SARS-CoV-2 cell entry, resulting in the inhibition of viral RNA replication and protein expression. Fröba et al and Varese et al reported that iota-carrageenan inhibits the replication of SARS-CoV-2 in various cell lines [ 8 , 9 ], and iota-carrageenan also inhibited the variants alpha, beta, gamma, and delta [ 9 ].…”

“…Recently, it was reported that iota-carrageenan inhibits SARS-CoV-2 replication in various cell lines [ 7 , 8 ] and also inhibits replication of its variants, alpha, beta, gamma, and delta [ 9 ]. Lambda-carrageenan has been reported to have antiviral effects against SARS-CoV-2 in vitro [ 10 ].…”

Antiviral Activity and Mechanisms of Seaweeds Bioactive Compounds on Enveloped Viruses—A Review

“…The study of Varese et al [162] assessed the in vitro effect of Ì-carrageenan on the Calu-3 cell line, which comes from a submucosal adenocarcinoma of the bronchi, a line considered as a suitable in vitro model of the upper airway epithelium. The study revealed that sterile nasal spray solutions prepared with different concentrations of Ì-carrageenan and sodium chloride inhibits infection of SARS-CoV-2 in Calu-3 cells in a dose-dependent manner, with an inhibition also present at low Ì-carrageenan concentrations.…”

A review on the immunomodulatory properties of functional nutraceuticals as dietary interventions for children to combat COVID-19 related infections

“…In children infected with the common cold virus, the direct administration of carrageenan via nasal spray reduces symptoms of cold (Bodenteich et al 2013 ). The polysaccharide inhibits the first stage of viral replication by attaching to the cell surface of the virus and prevents virus entry through its binding activity (Gonzalez et al 1987 ; Varese et al 2021 ). Carrageenan is used as nasal and mouth sprays that have the potential to act as a first line defense by inhibiting the infection and transmission of SARS-CoV-2.…”