ABSTRACT
BACKGROUND: The main protease (Mpro) is a crucial target for severe acute respiratory syndrome coronavirus (SARS-CoV-2). Chitooligosaccharide (CS) has broad-spectrum antiviral activity and can effectively inhibit the activity of SARS-CoV. Here, based on the high homology between SARS-CoV-2 and SARS-CoV, this study explores the effect and mechanism of CS with various molecular weights on the activity of SARS-CoV-2 Mpro. METHODS: We used fluorescence resonance energy transfer (FRET), UV-Vis, synchronous fluorescence spectroscopy, circular dichroism (CD) spectroscopy and computational simulation to investigate the molecular interaction and the interaction mechanism between CS and SARS-CoV-2 Mpro. RESULTS: Four kinds of CS with different molecular weights significantly inhibited the activity of Mpro by combining the hydrogen bonding and the salt bridge interaction to form a stable complex. Glu166 appeared to be the key amino acid. Among them, chitosan showed the highest inhibition effect on Mpro enzyme activity and the greatest impact on the spatial structure of protein. Chitosan would be one of the most potential anti-viral compounds. CONCLUSION: This study provides the theoretical basis to develop targeted Mpro inhibitors for the screening and application of anti-novel coronavirus drugs.
ABSTRACT
Under the influence of the COVID-19, people's awareness of physical health and immunity has increased significantly. Chitooligosaccharide is an oligomer of β-(1, 4)-linked D-glucosamine, furthermore, is one of the most widely studied immunomodulators. Chitooligosaccharide can be prepared from the chitin or chitosan polymers through enzymatically, chemically or physically processes. Chitooligosaccharide and its derivatives have been proven to have a wide range of biological activities including intestinal flora regulation, immunostimulant, anti-tumor, anti-obesity and anti-oxidation effects. This review summarizes the latest research of the preparation methods, biological activities in immunity and safety profiles of Chitooligosaccharide and its derivatives. We recapped the effect mechanisms of Chitooligosaccharide basing on overall immunity. Comparing the effects of Chitooligosaccharide with different molecular weights and degree of aggregation, a reference range for usage has been provided. This may provide a support for the application of Chitooligosaccharide in immune supplements and food. In addition, future research directions are also discussed. © 2023, Sociedade Brasileira de Ciencia e Tecnologia de Alimentos, SBCTA. All rights reserved.
ABSTRACT
Under the influence of the COVID-19, people's awareness of physical health and immunity has increased significantly. Chitooligosaccharide is an oligomer of β-(1, 4)-linked D-glucosamine, furthermore, is one of the most widely studied immunomodulators. Chitooligosaccharide can be prepared from the chitin or chitosan polymers through enzymatically, chemically or physically processes. Chitooligosaccharide and its derivatives have been proven to have a wide range of biological activities including intestinal flora regulation, immunostimulant, anti-tumor, anti-obesity and anti-oxidation effects. This review summarizes the latest research of the preparation methods, biological activities in immunity and safety profiles of Chitooligosaccharide and its derivatives. We recapped the effect mechanisms of Chitooligosaccharide basing on overall immunity. Comparing the effects of Chitooligosaccharide with different molecular weights and degree of aggregation, a reference range for usage has been provided. This may provide a support for the application of Chitooligosaccharide in immune supplements and food. In addition, future research directions are also discussed. © 2023, Sociedade Brasileira de Ciencia e Tecnologia de Alimentos, SBCTA. All rights reserved.
ABSTRACT
AIMS: The discovery of antiviral substances to respond to COVID-19 is a global issue, including the field of drug development based on natural materials. Here, we showed that chitosan-based substances have natural antiviral properties against SARS-CoV-2 in vitro. METHODS AND RESULTS: The molecular weight of chitosan-based substances was measured by the gel permeation chromatography analysis. In MTT assay, the chitosan-based substances have low cytotoxicity to Vero cells. The antiviral effect of these substances was confirmed by quantitative viral RNA targeting the RdRp and E genes and plaque assay. Among the substances tested, low molecular weight chitooligosaccharide decreased the fluorescence intensity of SARS-CoV-2 nucleocapsid protein of the virus-infected cells in a dose-dependent manner. CONCLUSIONS: In conclusion, the chitooligosaccharide, a candidate for natural treatment, has antiviral effects against the SARS-CoV-2 virus in vitro. SIGNIFICANCE AND IMPACT OF STUDY: In this study, it was suggested for the first time that chitosan-based substances such as chitooligosaccharide can have an antiviral effect on SARS-CoV-2 in vitro.