ABSTRACT
Beginning in the month of December 2019, China reported a novel coronavirus in the people of Wuhan, Hubei Province, China. This was later officially recognized as coronavirus disease 2019 (COVID-19) and found to be caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Its entire spectrum ranges from gentle, self-restraining respiratory tract illness to extreme progressive pneumonia, multiorgan failure, and fatality. As there are no particular remedial agents for SARS-CoV-2, it has become a great challenge for scientists to develop a suitable vaccine to treat it. This chapter highlights the key role in pursuance of the current existing antiviral drugs as regards their use in the previous epidemics. © 2022 Elsevier Inc. All rights reserved.
ABSTRACT
The novel coronavirus disease 2019 that is associated with respiratory illness has become a new threat to human health. This disease is rapidly spreading among the human population but unfortunately, there is no specific medication to treat it except the efforts geared toward repurposing of the existing drugs of influenza, HIV and hepatitis. Several research groups from various countries released genome and amino acid sequences of the SARS-CoV-2 using different bioinformatics tools and software. The field of bioinformatics utilizes the in silico tools that are useful in analyzing the new genes, whole genome, or proteomes. It plays a major role in sequence analysis and annotations in finding therapeutic drug targets. The possible small molecule or bioactive ligands will be docked against the modeled SARS-CoV-2 protein (involved in the host-pathogen infection) to check their inhibition activity and the highly potent protein–ligand complex is further considered for molecular dynamics simulation studies. © 2022 Elsevier Inc. All rights reserved.
ABSTRACT
Coronaviruses (CoVs), classified into four genera, viz., alpha-, beta-, gamma-, and Delta-CoV, represent an important group of diverse transboundary pathogens that can infect a variety of mammalian and avian species including humans, animals, poultry, and non-poultry birds. CoVs primarily infect lung and gut epithelial cells, besides monocytes and macrophages. CoVs have high mutation rates causing changes in host specificity, tissue tropism, and mode of virus excretion and transmissions. The recent CoV zoonoses are SARS, MERS, and COVID-19 that are caused by the transmission of beta-CoVs of bats to humans. Recently, reverse zoonoses of the COVID-19 virus have been detected in dogs, tigers, and minks. Beta-CoV strains also infect bovine (BCoV) and canine species (CRCoV);both these beta-CoVs might have originated from a common ancestor. Despite the high genetic similarity between BCoV, CRCoV, and HCoV-OC43, these differ in species specificity. Alpha-CoV strains infect canine (CCoV), feline (FIPV), swine (TGEV and PEDV), and humans (HCoV229E and NL63). Six coronavirus species are known to infect and cause disease in pigs, seven in human beings, and two in dogs. The high mutation rate in CoVs is attributed to error-prone 3′-5′ exoribonuclease (NSP 14), and genetic recombination to template shift by the polymerase. The present compilation describes the important features of the CoVs and diseases caused in humans, animals, and birds that are essential in surveillance of diverse pool of CoVs circulating in nature, and monitoring interspecies transmission, zoonoses, and reverse zoonoses. © 2021, Editorial board of Journal of Experimental Biology and Agricultural Sciences. All rights reserved.
ABSTRACT
The novel coronavirus pandemic has spread over in 213 countries as of July 2020. Approximately 12 million people have been infected so far according to the reports from World Health Organization (WHO). Preventive measures are being taken globally to avoid the rapid spread of virus. In the current study, an in silico approach is carried out as a means of inhibiting the spike protein of the novel coronavirus by flavonoids from natural sources that possess both antiviral and anti-inflammatory properties. The methodology is focused on molecular docking of 10 flavonoid compounds that are docked with the spike protein of SARS-CoV-2, to determine the highest binding affinity at the binding site. Molecular dynamics simulation was carried out with the flavonoid-protein complex showing the highest binding affinity and highest interactions. The flavonoid naringin showed the least binding energy of -9.8 Kcal/mol with the spike protein which was compared with the standard drug, dexamethasone which is being repurposed to treat critically ill patients. MD simulation was carried out on naringin-spike protein complex for their conformational stability in the active site of the novel coronavirus spike protein. The RMSD of the complex appeared to be more stable when compared to that of the protein from 0.2 nm to 0.4 nm. With the aid of this in silico approach further in vitro studies can be carried out on these flavonoids against the novel coronavirus as a means of viral protein inhibitors.