General overview on SARS-CoV-2 and potential role of natural compounds as antiviral drugs targeting SARS-CoV-2 proteins

Abstract

Purpose: The novel coronavirus disease namely COVID-19 is a viral disease induced by severe acute respiratory syndrome coronavirus (SARS-CoV-2). The cases were first reported in Wuhan, China, by the end of 2019 and subsequently spread worldwide. The virus can be transferred through direct or indirect contact and leads to several manifestations; the most common are fever, dry cough, pneumonia, and acute respiratory distress syndrome (ARDS). COVID-19 has caused massive human and economic losses, posing an ongoing threat. Understanding the current situation and developing a treatment which can be both safe and effective has become essential. In this regard, natural products could be an important resource in the development of treatment for COVID-19, as they have contributed to the treatment of other viruses in the past. This review aims to understand the cellular machinery of SARS-CoV-2 and to identify its drug targets. Methods: Emphasis has been given on the literature survey based on in vitro, in vivo, and in silico studies of natural products as anti-SARS-CoV-2. The important role of these compounds in boosting the immune system was also highlighted. Results: It was found that some natural products showed prominent antiviral activity against coronaviruses through impeding the main machinery used in their pathogenesis and replication cycle. Based on in vitro, in vivo, and in silico investigations, several classes of secondary metabolites, particularly polyphenols, have the ability to disrupt the interaction between SARS-CoV-2 S protein and the ACE2 receptor, resulting in virus entry inhibition. As well as the ability to block the activity of several enzymes involved in the virus replication cycle, including, 3CLpro, PLpro and RdRp. On the other hand, several vitamins and minerals can improve the immune response and are useful for COVID-19 prevention. Essential oils also show the ability to disrupt the fluidity of the virus envelope. Conclusion: Many phytonutrients are counted as bioactive components against SARS-CoV-2, phenolic compounds by their potent mechanisms of action via the immune system rank first. Group B vitamins, vitamins A, C and E as well as minerals such as zinc, selenium and magnesium also play an important role in in preventing the attack by this virus.