[Chitosan antiviral activity: dependence on structure and depolymerization method]

Area of Science:

• Biochemistry
• Polymer Science
• Virology

Context:

• Chitosan, a polysaccharide derived from chitin, possesses inherent biological activities.
• Modifications of chitosan, such as hydrolysis, can yield derivatives with altered properties and enhanced functionalities.
• Investigating the antiviral potential of chitosan derivatives is crucial for developing novel therapeutic agents.

Purpose:

• To synthesize low-molecular-weight (LM) chitosan derivatives using enzymatic (lysozyme) and chemical (hydrogen peroxide) hydrolysis.
• To characterize the antiviral activity of these LM chitosan derivatives against the tobacco mosaic virus (TMV).
• To evaluate the influence of polymerization degree and degree of acetylation (DA) on the antiviral efficacy of chitosan derivatives.

Summary:

• Low-molecular chitosan derivatives (2-17 kDa) were produced via enzymatic and chemical hydrolysis of chitosans with varying degrees of acetylation (25%, 17%, 1.5%).
• Purification involved dialysis, ultrafiltration, and gel-penetrating chromatography.
• The LM chitosans demonstrated significant inhibition (50-90%) of TMV-induced local necroses.
• Antiviral activity was inversely correlated with the polymerization degree.
• Enzymatically hydrolyzed chitosan derivatives exhibited higher antiviral activity compared to chemically hydrolyzed ones.
• The degree of acetylation had a minimal impact on the observed antiviral activity.

Impact:

• This study highlights the potential of LM chitosan derivatives as effective antiviral agents against plant viruses like TMV.
• The findings suggest that enzymatic hydrolysis is a promising method for producing highly active chitosan-based antiviral compounds.
• The results provide valuable insights for the rational design of chitosan derivatives for agricultural and potentially pharmaceutical applications.