One different technique to avoidance and therapy of influenza is the generation of a protective bodily barrier in the nasal cavity with carrageenans, substantial molecular excess weight sulphated polysaccharides derived from purple seaweed. 3 principal forms of carrageenans have been discovered kappa, iota and lambda. They vary from every single other in sulphation diploma, solubility and gelling attributes. Carrageenan is in prevalent professional use as an additive contributing to the texture and balance of numerous processed meals and beauty items, which include some brand names of sexual lubricant. Because highquality carrageenan preparations look to have a very good basic safety profile for long-phrase use and can inhibit HIV bacterial infections in model techniques, medical research were being conducted to validate the usefulness of carrageenan as a vaginal microbicide for the prevention of HIV-1 transmission. Reasons for the failure of these studies are manifold and strategies to increase the efficacy of these topical formulations are in the target of recent investigation. The antiviral probable of carrageenan and other sulphated polysaccharides in vitro against infections by various enveloped viruses this kind of as herpes simplex virus , human cytomegalovirus , vesicular stomatitis virus , Sindbis virus, and human immunodeficiency virus has been explained a lot more than 20 yrs back , and has been reviewed lately. More recent scientific tests have confirmed the efficacy of carrageenans from distinct maritime algal species in animal models of HSV and CMV bacterial infections in vivo. The inhibitory system of carrageenans on virus replication seems to comprise early activities of the an infection cycle, attachment and entry of virus particles , and is dependent on the type of polysaccharide as properly as the serotype of the virus and the host cells. Iota-carrageenan has been reported to inhibit the an infection of selected non-enveloped human viral pathogens, human hepatitis A and papilloma viruses in vitro. Furthermore, iota-carrageenan interfered specially with the adsorption of HPV16 capsids to human sperm cells. These findings inspired the authors to propose clinical trials in buy to determine regardless of whether carrageenan-based mostly goods are successful as topical microbicides versus genital HPVs. We recently could present that iota-carrageenan is a powerful anti-rhinoviral material in vitro and consequently an great applicant for the remedy of infections that predominantly take place in the nasal cavity and higher respiratory tract. For that reason, we have been interested whether or not carrageenans and in specific iota-carrageenan have any antiviral activity in opposition to human influenza A viruses. We identified the sensitivity of the influenza virus strain H1N1 and the formerly pandemic H3N2 to carrageenans of subtypes iota and kappa by plaque reduction assays in MDCK cells. The benefits are summarized in Desk 1. The two carrageenan forms inhibited plaque formation of each viruses examined even though to a different degree. Iota-carrageenan was the most lively material in all experiments followed by kappa-carrageenan. The purity of iota- as nicely as kappacarrageenan preparations analyzed by nuclear magnetic resonance spectroscopy was increased than 95 and the molecular excess weight of the two polymers effectively over 1009000. However, the inhibitory probable of iota-carrageenan with IC50 values of all over in H1N1 and .04 mg/ml in H3N2 infections was up to ten periods greater when compared to kappacarrageenan.