Immunomodulatory Activity of Natural Polysaccharides in Combating Covid -19, Cancer, Inflammatory Disorders: A Review

Abstract

Natural polysaccharides are a source of carbohydrates with potent biological functions that can be explored for increasing its utilization in the field of food and medicine. If characterized, studied and explored, they would have a vital contribution in the health care policy of the world, and more particularly in numerous developing countries in the next decades. There are thousands of polysaccharides isolated from various natural sources which can affect the immune system by stimulating the immune response or by influencing the formation of antibodies. They consist of various monomer units such as beta-glucan, mannan, arabinose, galacturonic acid, fucoidan, laminarin, carrageenan etc. These polysaccharides follow different mechanisms to show the desired biological activity. This review presents a detailed account of the immunomodulatory properties of polysaccharides isolated from microorganisms, plants and marine sources. The outbreak of the novel coronavirus disease COVID-19 which is caused by the SARS-COV-2provide full description of SARS-COV-2 virus has been a serious threat to public health as there are no clinically significant vaccines yet produced for its prevention. Polysaccharide with good immunomodulator and antivirus activity have potent anti-coronavirus applications. This study focuses on the advancements in the inhibition of SARS-COV-2 virus responsible for COVID-19. It also gives a detailed account of the anti-cancer activity of various natural polysaccharides and anti-inflammatory effects. The established therapy strategy for the treatment of cancer and inflammatory disorders involves the use of various chemotherapeutic agents and non-steroidal anti-inflammatory drugs respectively, which have prominent side effects. Polysaccharides obtained from natural sources have gained attention owing to their safety and less side effects. The mechanism of action of the polysaccharides showing immunomodulatory activity owing to treatment of COVID-19, cancer and inflammatory disorders has been discussed in the review. Most polysaccharides are tested using preclinical animal models or by clinical trials. This review will provide guidelines for the development of new formulations for utilising the various biological activity of the natural polysaccharides.