In vitro characterization of the antiviral activity of fucoidan from Cladosiphon okamuranus against Newcastle Disease Virus

Abstract

BackgroundNewcastle Disease Virus (NDV) causes a serious infectious disease in birds that results in severe losses in the worldwide poultry industry. Despite vaccination, NDV outbreaks have increased the necessity of alternative prevention and control measures. Several recent studies focused on antiviral compounds obtained from natural resources. Many extracts from marine organisms have been isolated and tested for pharmacological purposes, and their antiviral activity has been demonstrated in vitro and in vivo. Fucoidan is a sulfated polysaccharide present in the cell wall matrix of brown algae that has been demonstrated to inhibit certain enveloped viruses with low toxicity. This study evaluated the potential antiviral activity and the mechanism of action of fucoidan from Cladosiphon okamuranus against NDV in the Vero cell line.MethodsThe cytotoxicity of fucoidan was determined by the MTT assay. To study its antiviral activity, fusion and plaque-forming unit (PFU) inhibition assays were conducted. The mechanism of action was determined by time of addition, fusion inhibition, and penetration assays. The NDV vaccine strain (La Sota) was used in the fusion inhibition assays. PFU and Western blot experiments were performed using a wild-type lentogenic NDV strain.ResultsFucoidan exhibited antiviral activity against NDV La Sota, with an obtained IS50 >2000. In time of addition studies, we observed viral inhibition in the early stages of infection (0–60 min post-infection). The inhibition of viral penetration experiments with a wild-type NDV strain supported this result, as these experiments demonstrated a 48% decrease in viral infection as well as reduced HN protein expression. Ribavirin, which was used as an antiviral control, exhibited lower antiviral activity than fucoidan and high toxicity at active doses. In the fusion assays, the number of syncytia was significantly reduced (70% inhibition) when fucoidan was added before cleavage of the fusion protein, perhaps indicating a specific interaction between fucoidan and the F0 protein.ConclusionThe results of this study suggest that fucoidan from C. okamuranus represents a potential low-toxicity antiviral compound for the poultry industry, and our findings provide a better understanding of the mode of action of sulfated polysaccharides.

Total phenolic content and biological activities of enzymatic extracts from Sargassum muticum (Yendo) Fensholt

“…Antiviral effects of brown algae are usually shown by their polysaccharides as explained by previous studies (Ahn et al 2006;Lee et al 2011;Elizondo-Gonzalez et al 2012). However, for the past few years, several studies concerning the antiviral effects of brown algae phlorotannins have appeared.…”

Marine Algal Antioxidants as Potential Vectors for Controlling Viral Diseases

“…The polysaccharides fucoidan, based on the sulfated L-fucose, possesses various biological activities, among them activities against many RNA and DNA viruses such as HIV, HSV1-2, dengue virus, and cytomegalovirus [81]. Fucoidans exert their antiviral activities by blocking the interaction of viruses with the cells, thus inhibiting viral-induced syncytium formation [82]. This property led to attachment of fucoidan to the F0 protein resulting in a great antiviral potency of fucoidan, e.g., higher than the antiviral drug ribavirin [83].…”

Antimicrobial potential of macro and microalgae against pathogenic and spoilage microorganisms in food

“…The main substances from algae that have been related to antiviral potential are sulfated polysaccharides, including fucoidan, sulfoglycolipids, carrageenans, sesquiterpene hydroquinones, etc. (Elizondo-Gonzalez et al, 2012). Suppression of DNA replication and inhibition of host cell colonization by the virus are some of the effects of algal polysaccharides (e.g.…”