Antiviral Potency of Chitosan, Its Derivatives, and Nanocomposites

Abstract

Chitosan is a linear polysaccharide consisting of d-glucosamine and N-acetyl-d-glucosamine units. It is manufactured from chitin (a naturally abundant polysaccharide), extracted from the exoskeleton of crustaceans, squids, or fungi walls. Chitosan has a large number of amino groups making it positively charged moiety and, hence, is soluble in neutral as well as acidic solutions. It possesses a great deal of physical, chemical, and biological properties including biodegradability, biocompatibility, non-toxicity, display of antibacterial, antifungal and antiviral effects, and adsorption activity for heavy metal ions leading to its variety of applications in fields like water-waste management and treatment, cosmetic industry, food industry, drug and/or gene delivery, and wound healing and dressing. However, it has some shortcomings like high density because of extensive hydrogen bonding and high viscosity, hampering its activity. For this, many researchers over the years have functionalized chitosan and made use of nanoparticles resulting in chitosan nanocomposites, enhancing its properties. In this chapter, the focus would be on the noteworthy application of chitosan, modified chitosan, and its nanocomposites as viable antiviral agents against various animal and plant viruses. In fact, they have also been studied as a potential antiviral agent against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) which caused the Coronavirus Disease of 2019 (COVID-19) pandemic, which will also be discussed in detail.