Virus infection seriously endangers people's lives and health.
By the end of April 2011, 63 antiviral drugs had been approved for clinical use worldwide, including nucleoside compounds, non-nucleoside compounds and substituted pyrimidines.
However, there are still many problems such as low efficacy, high side effects, easy drug resistance and easy recurrence after drug withdrawal. Therefore, the research and development of safe and effective new antiviral drugs is still an urgent need in clinical practice.
Polysaccharide sulfate, whether extracted naturally or modified by sulfuration, has shown a variety of antiviral activities.
Marine organisms are important sources of polysaccharide sulfate. For example, polysaccharide sulfate with unique structure exists in Marine plants (algae), animals and microorganisms. Its extensive antiviral activity has attracted increasing attention and become an important direction of antiviral drug development.
In addition, Marine polysaccharide sulfate also has low cytotoxicity, small side effects, and can enhance the characteristics of the body immunity, with the potential to become a new antiviral drugs.
Antiviral mechanism of Marine polysaccharide sulfate:
1, direct killing virus activity sulfate polysaccharides can through its negative charge and the surface of the virus directly, so as to inhibit the ability to infect the virus, or direct killing virus lost the ability to infect;
2, block the virus adsorption of, or intrusion into, a process on the surface of the cell types of heparin sulfate proteoglycan virus infection is the initial receptors, Marine polysaccharide sulfate have strong polyanion nature, with a virus or virus receptors on the surface of the cells, prevent virus adsorption or suppress the virus into the cell replication cycle in different stages of the one;
3. Inhibition of viral transcription and replication Marine polysaccharide sulfate can inhibit viral transcription and replication by directly interfering with viral replication related enzymes, or by acting on relevant targets in host cells;
4. Enhance the antiviral immunoactivity of the body; after the virus invades the body, the immune response of the body can be triggered to remove the virus. As long as the immune regulation of ocean sulfated polysaccharides is based on the regulation of macrophages and the induction of immune cytokines, the antiviral immunity can be indirectly played by activating the innate immunity;
Structure-activity relationship of the antiviral activity of Marine polysaccharide sulfate
1. The influence of sulfate groups on the polyanion characteristics of Marine sulfated polysaccharides is closely related to the distribution of sulfate groups.
2. Molecular weight and molecular structure influence the molecular weight, main chain structure (such as monosaccharide composition, glycoside bond type), branch chain characteristics (distribution position on the main chain, degree of substitution) and advanced structure of sulfate polysaccharides will affect their antiviral activity.
Generally speaking, the higher the molecular weight, the better the activity. For example, the anti-hiv activity of dextran sulfate is proportional to the molecular weight.
3. Effects of structural modification and recombination with polysaccharide sulfate or oligosaccharide as the basic structural unit, structural modification (such as adding hydrophobic functional groups, etc.) or changing its spatial arrangement can improve the antiviral activity, which provides a new idea for the development of new polysaccharide sulfate antiviral drugs;