Current Landscape of Natural Products against Coronaviruses: Perspectives in COVID-19 Treatment and Anti-viral Mechanism.

Background: SARS-CoV-2 is a coronavirus, and the infection by SARS-CoV-2, termed as COVID-19, was first reported in Wuhan, China, at the end of 2019, and this outbreak became a pandemic in February of 2020. Till now, there is no effective drug or vaccine against this virus that can make a complete cure; however, a number of drugs are in trials.

Objectives: In this review, we have focused on an alternative therapeutic approach using natural products utilizing the host anti-viral responses for resolving COVID-19 pathogenesis.

Methods: We have searched databases like PubMed, Scopus, Web of Science, and Google Scholar for articles related to natural products and viral diseases, with a specific focus on coronaviruses, as well as other RNA viruses and recent updates on the COVID-19 pandemic, and collected articles and reviewed them comprehensively.

Results: Scientific studies clarified the viral pathogenesis that involved viral entrance into host cells and anti-viral response inside the cells, which can be effectively targeted by numerous natural compounds from different sources. Many of these compounds can potentially target viral genomic material or protein machinery. Natural products that were found effective against other coronaviruses, especially SARS-CoV or MERS-CoV (which emerged in 2002 and 2012, respectively), might be effective against SARS-CoV-2 due to their structural similarities.

Conclusion: COVID-19 pandemic is a global emergency thus, urgent drug development is necessary. Natural products can be the biggest source of drugs, as they have been found to be effective in other coronaviruses previously; however, time is required to establish the clinical success of these drugs for clinical applications.