Iota-Carrageenan Nasal Spray Protects Mice against Influenza

These large, highly flexible molecules curl forming helical structures that give them the ability to form a variety of different gels at room temperature. They are widely used in the food and other industries as thickening and stabilizing agents. All carrageenans are high molecular weight polysaccharides made up of repeating galactose units and 3,6 anhydrogalactose (3,6-AG), both sulfated and nonsulfated. The units are joined by alternating alpha 1-3 and beta 1-4 glycosidic linkages. Iota-carrageenan forms soft gels in the presence of calcium ions. It is produced mainly from Eucheuma spinosum.

The Austrian biotechnology company Marionmed Biotechnolgie GmbH (Vienna, Austria) was founded with the objective of finding innovative therapies for respiratory diseases. Since an iota-carrageenan based nasal spray has already been approved for use a cold remedy, investigators at Marionmed decided to test it against other respiratory diseases.

In the current study, a commercially available nasal spray containing iota-carrageenan was tested in an influenza A mouse infection model. Results published in the December 14, 2010, online edition of the journal PLoS ONE revealed that treatment of mice starting up to 48 hours after infection with a lethal dose of influenza A PR8/34 H1N1 virus with iota-carrageenan resulted in strong protection -- similar to mice treated with oseltamivir (Tamiflu). The polymer directly bound to the influenza viruses, effectively blocking them from attaching to cells and spreading further.

"Influenza viruses still represent a substantial threat to public health on a global scale and with increasing viral resistance to Tamiflu, the need for alternatives has never been greater,” said senior author Dr. Andreas Grassauer, CEO of Marinomed Biotechnolgie GmbH. "This study confirms that iota-carrageenan can be used as an alternative to neuraminidase inhibitors, and should be further tested for prevention and treatment of influenza A in clinical trials in humans.”

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Marionmed Biotechnolgie GmbH