Characterization and Comparison of the Structural Features, Immune-Modulatory and Anti-Avian Influenza Virus Activities Conferred by Three Algal Sulfated Polysaccharides.

Lin Song,Xiaolin Chen,Fubo Zhang,Yang Yue,Linfeng Hu,Kecheng Li,Xiaodong Liu,Pengcheng Li

doi:10.3390/md14010004

Abstract

Three marine macroalgae, i.e., Grateloupia filicina, Ulva pertusa and Sargassum qingdaoense, were selected as the deputies of Rhodophyta, Chlorophyta and Ochrophyta for comparative analysis of the molecular structures and biological activities of sulfated polysaccharides (SP). The ratio of water-soluble polysaccharides, the monosaccharide composition and the sulfated contents of three extracted SPs were determined, and their structures were characterized by Fourier transformation infrared spectroscopy. In addition, biological activity analysis showed that all three SPs had immune-modulatory activity both in vitro and in vivo, and SPs from S. qingdaoense had the best effect. Further bioassays showed that three SPs could not only enhance the immunity level stimulated by inactivated avian influenza virus (AIV) in vivo but also significantly inhibited the activity of activated AIV (H9N2 subtype) in vitro. G. filicina SP exhibited the strongest anti-AIV activity. These results revealed the variations in structural features and bioactivities among three SPs and indicated the potential adjuvants for immune-enhancement and anti-AIV.

Highlights

Sulfated polysaccharides have attracted increasing attention due to their diversified biological and pharmacological activities, such as anti-viral, immune enhancement, anti-tumor, anti-infective and antioxidant effects (Table 1) [1,2,3,4]
Individual variations were found in the components of monosaccharides, and the most abundant components in UPP, GFP and SQP were rhamnose, galactose, and fucose, respectively
Further experiments revealed that the sulfate polysaccharides enhanced the immunity level stimulated by inactivated avian influenza virus (AIV) in vivo and significantly inhibited the activity of activated AIV in vitro

Summary

Introduction

Sulfated polysaccharides have attracted increasing attention due to their diversified biological and pharmacological activities, such as anti-viral, immune enhancement, anti-tumor, anti-infective and antioxidant effects (Table 1) [1,2,3,4]. Various biological functions of sulfated polysaccharides from marine algae have been reported in recent decades, but these analyses were mainly focused on a single species (Table 1) [8,9,10,11]. The sulfated polysaccharides obtained from green alga Enteromorpha clathrata showed immune-enhancement activity that could stimulate TNF-α expression in serum and induce lymphocyte proliferation [9]. The sulfated polysaccharide purified from Sargassum horneri was reported to have antitumor activity that could inhibit the growth of human colon cancer DLD cells [12].

Results

Discussion

Conclusion