Structure-based inhibitor design and repurposing clinical drugs to target SARS-CoV-2 proteases

SARS-CoV-2, the coronavirus responsible for the current COVID-19 pandemic, encodes two proteases, 3CLpro and PLpro, two of the main antiviral research targets. Here we provide an overview of the structures and functions of 3CLpro and PLpro and examine strategies of structure-based drug designing and drug repurposing against these proteases. Rational structure-based drug design enables the generation of potent and target-specific antivirals. Drug repurposing offers an attractive prospect with an accelerated turnaround. Thus far, several protease inhibitors have been identified, and some candidates are undergoing trials that may well prove to be effective antivirals against SARS-CoV-2.

Pharmaceutical interest of in-silico approaches

The virtual environment within the computer using software performed on the computer is known as in-silico studies. These drugs designing software play a vital task in discovering new drugs in the field of pharmaceuticals. These designing programs and software are employed in gene sequencing, molecular modeling, and in assessing the three-dimensional structure of the molecule, which can further be used in drug designing and development. Drug development and discovery is not only a powerful, extensive, and an interdisciplinary system but also a very complex and time-consuming method. This book chapter mainly focused on different types of in-silico approaches along with their pharmaceutical applications in numerous diseases.

Metal Complexes and Their Potential Therapeutic Role Against COVID-19: Recent Developments in Drug Designing

COVID-19 is a global pandemic caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2). Being associated with high mortality rates, this pandemic has forced several countries worldwide to impose complete lockdowns to limit the spread of infection. Despite the development of various vaccines, there is still an urgent need to design novel treatments backed with safety data for fighting SARS-CoV-2 and its various mutants. Currently, scientists are putting their strenuous efforts into finding the best treatment option for COVID-19. In this regard, metal complexes being active antiviral agents and immunity enhancers have great potential against SARS-CoV-2. Herein, metal complexes' therapeutic role and significance against treating SARS-CoV-2 or any of its target proteins are discussed.

Computational Investigations on Interactions Between DNA and Flavonols

Today, the main task of researchers is to study and develop drugs that are less toxic and have lesser side effects. The principal motive of this research is to study and analyze the interaction between naturally active compounds flavonoids with biomolecule DNA. Since the interaction between DNA and ligand is essential in drug designing, this study will provide a good base for further research and development of less toxic and more efficient drugs for various diseases. The selected compounds for this study are Kaempferide, Kaempferol, Morin, and Rutin. They all fall into the category ‘flavonols’ of flavonoids. Computational methods are implemented for theoretical drug designing. These are molecular optimization, molecular docking, and molecular dynamics. Computational results are compared with experimental data from previous studies. Molecular docking gives the most preferred orientation of ligands within DNA, and Molecular Dynamics provides the details about the DNA-ligand complex with respect to time. Free energy calculations were also performed by implementing MMPBSA and MMGBSA calculations.

Bioinformatics approaches to investigate the phytochemicals of Centella asiatica against the main protease of SARS-CoV-2

The recent pandemic caused by the novel coronavirus SARS-CoV-2 has impacted global health by increasing mortality and unexpected infection rate. Extensive clinical research is undergoing to repurposing the old drug against this virus. So, this is an emerging need to develop therapy against the virus. Plant-derived natural products have proven to be potent therapeutics for several infections and diseases. Centella asiatica, is a native plant of the Indian subcontinent, has been vastly using as folk medicine against diseases including infectious diseases. So, using bioinformatics approach we identified and checked the phytochemicals of the plant as inhibitors against the main protease (Mpro), the key regulatory enzyme of the SARS-CoV-2 lifecycle. Computer-aided drug designing methods were performed to reveal the best nine drug-like phytochemicals those theoretically have the higher binding affinity of inhibiting Mpro. This outcome may direct to the development of potent therapeutics against the SARS-CoV-2 and demands experimental validation.

Nanotechnological Advancement in Antimicrobial Drug Designing

The global spread of multidrug-resistant (MDR) microbial infections is currently one of the most severe risks to global public health, with 10 million fatalities expected by 2050 unless action is taken. Nanotechnology has revolutionized science and medicine. The reliance on nanotechnology is growing. Nanoparticles have distinct properties that improve biological, chemical, and physical properties studied for various uses. A significant area of attention in the synthesis of nanoscale modulators is the utilization of crude formulations, retro-synthesized, and pure chemicals, mainly from herbal sources, with fewer adverse effects. Green chemistry has devised a tangential technique for synthesizing metals and metal oxides to produce nanoparticles. Plant extracts (leaves, stems, and shoots) and microorganisms (bacteria, fungus, and yeast) are used as reducing intermediates to make nanoparticles. Studies in microbiology have shown that nanoparticles kill bacteria, fungi, viruses, and protozoa. These green nanoparticles contain antibacterial, antifungal, and anti-inflammatory effects. Most nanoparticles have high antibacterial properties, indicating they may be used to combat diseases and biological contaminants. These nanoparticles have antibacterial action against pathogenic microorganisms that cause serious illnesses, including multidrug-resistant pathogens. The current research will pave the way for future applications and improved methods for producing nanoparticles, paving the way for an innovative route in nano-life sciences with widespread recognition.

Role of Disulfide Bonds in Membrane Partitioning of a Viral Peptide

The importance of disulfide bond in mediating viral peptide entry into host cells is well known. In the present work, we elucidate the role of disulfide (SS) bond in partitioning mechanism of membrane active Hepatitis A Virus-2B (HAV-2B) peptide, which harbours three cysteine residues promoting formation of multiple SS-bonded states. The inclusion of SS-bond not only results in a compact conformation but also induces distorted α-helical hairpin geometry in comparison to SS-free state, resulting in reduced hydrophobic exposure. Owing to this, the partitioning of HAV-2B peptide is completely or partly abolished. In a way, the disulfide bond regulates the partitioning of HAV-2B peptide, such that the membrane remodelling effects of this viral peptide are significantly reduced. The current findings may have potential implications in drug designing, targeting the HAV-2B protein by promoting disulfide bond formation within its membrane active region.