Apr 12, 2020

Inhibition of SARS-coronavirus infection in vitro

Posted by in category: biotech/medical


“During the SARS epidemic, Chen and colleagues included inhalation of NO gas in the treatment of a number of SARS patients. Medicinal NO gas, a gaseous blend of nitric oxide (0.8%) and nitrogen (99.2%), was given for three days or longer, initially at 30 ppm and then at 20 and 10 ppm on the second and third day (unpublished data). Their findings suggest not only an immediate improvement of oxygenation but also a lasting effect on the disease itself after termination of inhalation of NO.

NO is a key molecule in the pathogenesis of infectious diseases. In a variety of microbial infections, NO biosynthesis occurs through the expression of an inducible nitric oxide synthase (iNOS). This molecule has been reported to have antiviral effects against a variety of DNA and RNA viruses, including mouse hepatitis virus (MHV), a murine coronavirus.4 In a recent study, replication of two SARS-CoV isolates (FFM-1 and FFM-2) was shown to be greatly inhibited by glycyrrhizin, an active compound of liquorice roots.5 Glycyrrhizin upregulates the expression of iNOS and production of NO in macrophages.”

Introduction: The recent outbreak of severe acute respiratory syndrome (SARS) warrants the search for effective antiviral agents to treat the disease. This study describes the assessment of the antiviral potential of nitric oxide (NO) against SARS coronavirus (SARS-CoV) strain Frankfurt-1 replicating in African Green Monkey (Vero E6) cells.

Results: Two organic NO donor compounds, S-nitroso-N-acetylpenicillamine (SNAP) and sodium nitroprusside (SNP), were tested in a broad range of concentrations. The non-nitrosylated form of SNAP, N-acetylpenicillamine (NAP), was included as a control compound in the assay. Antiviral activity was estimated by the inhibition of the SARS-CoV cytopathic effect in Vero E6 cells, determined by a tetrazolium-based colorimetric method. Cytotoxicity of the compounds was tested in parallel.

Conclusion: The survival rate of SARS-CoV infected cells was greatly increased by the treatment with SNAP, and the concentration of this compound needed to inhibit the viral cytopathic effect to 50% was 222 μM, with a selectivity index of 3. No anti-SARS-CoV effect could be detected for SNP and NAP.

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