Preface

SARS-CoV-2 has several targets that are essential for viral transcription and replication. Therefore, their inhibition could disrupt the virus' life cycle. Among these targets are viral proteases and RNA helicase. SARS-CoV-2 has two proteases, the papain-like protease (PLpro) and the 3-chymotrypsin-like protease (3CLpro), also known as the main protease (Mpro). They are cysteine proteases responsible for the proteolytic processing of the polyproteins that are translated from the viral RNA. PLpro was reported to be responsible for the cleavage of the N-terminus of the viral polyprotein at three cleavage sites, leading to the production of non-structural proteins nsp1-3. Mpro was reported to catalyze the polyprotein cleavage at about eleven sites. This proteolytic process is essential for the production of the functional proteins responsible for viral replication. Moreover, PLpro was reported to be involved in suppressing the host immune response by causing de-ubiquitination and de-ISGylation of the host proteins. Therefore, these enzymes are significant targets for antiviral drugs against coronaviruses and their inhibitors would represent promising antiviral drug candidates.

This book includes five chapters that address several interesting and new approaches regarding non-conventional intervention strategies for viral infection, particularly SARS-CoV-2.

Chapter 1 is an introductory chapter on intervention therapeutic strategies against SARS-CoV-2. Chapter 2 discusses the repurposing of natural products to target COVID-19, including molecular targets and new avenues for drug discovery. Chapter 3 examines antiviral drugs and their roles in the treatment of coronavirus infection. Chapter 4 presents immunoinformatics and computer-aided drug design as novel approaches against emerging and re-emerging infectious diseases. Finally, Chapter 5 discusses the repurposing, repositioning, and reprofiling of antiviral agents to combat viral infections.

This book poses a balance between developments in scientific research and the premise that researchers must be able to absorb and link scientific advances with clinical practice so that the management of diseases can be based on sound physiological concepts.

> **Farid A. Badria, Ph.D.** Liver Research Lab, FAB-Lab, Faculty of Pharmacy, Pharmacognosy Department, Mansoura University, Mansoura, Egypt

**1**

**Chapter 1**

*Farid A. Badria*

**1. Introduction**

therapeutic strategies against SARS-CoV-2.

Accordingly, the founding factors of this vision will be:

• Protect the environment against all hazards.

against potential dangers.

The premises of this vision are:

Introductory Chapter:

An Intervention Therapeutic

Strategies against SARS-CoV-2

The objectives of this introductory chapter is to outline the possible intervention

• Treat the current diseases by introducing totally indigenous thought, ideas, raw materials and technology to produce a safe, effective, and economic therapy.

• Spread hygienic awareness and good sound health practices as a protection

○ A sound healthy environment embraces a sound and healthy society.

○ A healthy environment provides us with a cure to any ailment.

**2. A possible approach for intervention of SARS-CoV-2 infectivity**

and protein. The human cell entry by the virus was prompted upon S-protein (Spike protein), which resides in the envelope anchors to ACE2. Protease cleaved the S-protein into S-1 and S-2 fragments, whereas S-1 binds to ACE2. While S-2 was cleaved by serine protease enzyme (TMPRSS2), leading to membrane fusion. This

may halt the first step of infection with the virus, as presented in **Figure 1**.

SARS-CoV-2 genomic RNA is protected by two envelopes: phospholipid bilayer

○ An unhealthy environment is the source of all illnesses.

Upon such vision, all research projects, scientific creations, trouble-shooting and problem-solving techniques must be based on healthy environment. As a matter of fact, the environment has provided us with the best of everything, of food, water, air, and a cure for every illness. In our turn, we should make good use of God's blessings bestowed upon us through natural sources by which we can fight contagious diseases including COVID-19.
