Spectral characterization and biological studies of some ternary complexes with molecular docking investigations against MERS and SARS type coronaviruses

ABSTRACT. A series of ternary complexes with a Schiff base (HL1) derived from 2-hydrazinobenzimidazole and o-hydroxybenzophenone (primary ligand) have been prepared. Here, 1,10-phenanthroline acts as secondary ligand (L2). These metal complexes were investigated by UV-Vis, IR, 1H NMR and thermal techniques. The spectral data confirmed tridentate nature of the SB ligand with NNO type coordination, whereas the secondary ligand L2 (1,10-phenanthroline) coordinated through its two nitrogen atoms (NN type). These compounds possess distorted octahedral geometry. Moreover, these compounds were screened against B. subtilis and E. coli to evaluate their antibacterial activity. In addition, molecular docking studies were performed against MERS-CoV and SARS-CoV-2 main protease (Mpro). Moreover, DFT calculations and QSAR studies of the SB ligand were also performed.                     KEY WORDS: Ternary complexes, Spectral, Antibacterial, DFT, QSAR, Molecular docking studies   Bull. Chem. Soc. Ethiop. 2021, 35(3), 525-535. DOI: https://dx.doi.org/10.4314/bcse.v35i3.5

Comparative pathology, molecular pathogenicity, immunological features, and genetic characterization of three highly pathogenic human coronaviruses (MERS-CoV, SARS-CoV, and SARS-CoV-2)

The last two decades have witnessed the emergence of three deadly coronaviruses (CoVs) in humans: severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). There are still no reliable and efficient therapeutics to manage the devastating consequences of these CoVs. Of these, SARS-CoV-2, the cause of the currently ongoing coronavirus disease 2019 (COVID-19) pandemic, has posed great global health concerns. The COVID-19 pandemic has resulted in an unprecedented crisis with devastating socio-economic and health impacts worldwide. This highlights the fact that CoVs continue to evolve and have the genetic flexibility to become highly pathogenic in humans and other mammals. SARS-CoV-2 carries a high genetic homology to the previously identified CoV (SARS-CoV), and the immunological and pathogenic characteristics of SARS-CoV-2, SARS-CoV, and MERS contain key similarities and differences that can guide therapy and management. This review presents salient and updated information on comparative pathology, molecular pathogenicity, immunological features, and genetic characterization of SARS-CoV, MERS-CoV, and SARS-CoV-2; this can help in the design of more effective vaccines and therapeutics for countering these pathogenic CoVs.

Consecutive Hits of COVID-19 in India: The Mystery of Plummeting Cases and Current Scenario

The novel coronavirus disease 2019 (COVID-19)-related pandemic has been in existence for almost 2 years now after its possible emergence from a wet market in the city of Wuhan of the Chinese mainland. Evidence of the emergence and transmission of this virus was attributed to bats and pangolins. The causative virus, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has rapidly spread globally, affecting humans considerably with its current death toll to be over 4.7 million out of more than 233 confirmed cases as of September 2021. The virus is constantly mutating and continuously trying to establish itself in humans by increasing its transmissibility and virulence through its numerous emerging variants. Several countries have been facing multiple waves of COVID-19 outbreaks one after the other, putting the medical and healthcare establishments under tremendous stress. Although very few drugs and vaccines have been approved for emergency use, their production capabilities need to meet the needs of a huge global population. Currently, not even a quarter of the world population is vaccinated. The situation in India has worsened during the ongoing second wave with the involvement of virus variants with a rapid and huge surge in COVID-19 cases, where the scarcity of hospital infrastructure, antiviral agents, and oxygen has led to increased deaths. Recently, increased surveillance and monitoring, strengthening of medical facilities, campaigns of awareness programs, progressive vaccination drive, and high collaborative efforts have led to limiting the surge of COVID-19 cases in India to a low level. This review outlines the global status of the pandemic with special reference to the Indian scenario.

Modulation of host epigenome by coronavirus infections and developing treatment modalities for COVID-19 beyond genetics

The recent Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) outbreak has resulted in coronavirus disease 2019 (COVID-19) pandemic worldwide, affecting millions of lives. Although vaccines are presently made available, and vaccination drive is in progress to immunize a larger population; still the risk of SARS-CoV-2 infection and related mortality is persistent amid threats of the third wave of the ongoing pandemic. In the scenario of unavailability of robust and efficient treatment modalities, it becomes essential to understand the mechanism of action of the virus and deeply study the molecular mechanisms (both at the virus level and the host level) underlying the infection processes. Recent studies have shown that coronaviruses (CoVs) cause-specific epigenetic changes in the host cells to create a conducive microenvironment for replicating, assembling, and spreading. Epigenetic mechanisms can contribute to various aspects of the SARS-CoV-2 multiplication cycle, like expressing cytokine genes, viral receptor ACE2, and implicating different histone modifications. For SARS-CoV-2 infection, viral proteins are physically associated with various host proteins resulting in numerous interactions between epigenetic enzymes (i.e., histone deacetylases, bromodomain-containing proteins). The involvement of epigenetic mechanisms in the virus life cycle and the host immune responses to control infection result in epigenetic factors recognized as emerging prognostic COVID-19 biomarkers and epigenetic modulators as robust therapeutic targets to curb COVID-19. Therefore, this narrative review aimed to summarize and discuss the various epigenetic mechanisms that control gene expression and how these mechanisms are altered in the host cells during coronavirus infection. We also discuss the opportunities to exploit these epigenetic changes as therapeutic targets for SARS-CoV-2 infection. Epigenetic alterations and regulation play a pivotal role at various levels of coronavirus infection: entry, replication/transcription, and the process of maturation of viral proteins. Coronaviruses modulate the host epigenome to escape the host immune mechanisms. Therefore, host epigenetic alterations induced by CoVs can be considered to develop targeted therapies for COVID-19.

A phase 3, randomized, double-blind study of single-dose fosaprepitant for prevention of cisplatin-induced nausea and vomiting: results of an Indian population subanalysis

CONTEXT

Currently, there is limited data on the prevention of chemotherapy-induced nausea and vomiting (CINV) in Indian patients.

AIMS

This post hoc study assessed the efficacy and safety of fosaprepitant compared with aprepitant for prevention of CINV in the Indian population. A subgroup analysis was performed from data collected in a phase 3 study of intravenous (IV) fosaprepitant or oral aprepitant, plus the 5-HT 3 antagonist ondansetron and the corticosteroid dexamethasone, in cisplatin-naοve patients with solid malignancies.

MATERIALS AND METHODS

Patients scheduled to receive cisplatin (≥70 mg/m 2 ) were administered a single IV dose of fosaprepitant dimeglumine (150 mg) on day 1 or a 3-day dosing regimen of oral aprepitant (day 1:125 mg, days 2 and 3:80 mg) with standard doses of ondansetron and dexamethasone. Patients recorded nausea and/or vomiting episodes and their use of rescue medication and were monitored for adverse events (AEs) and tolerability.

STATISTICAL ANALYSIS USED

Differences in response rates between fosaprepitant and aprepitant were calculated using the Miettinen and Nurminen method.

RESULTS

In the Indian subpopulation (n = 372), efficacy was similar for patients in both the fosaprepitant or aprepitant groups; complete response in the overall, acute, and delayed phases and no vomiting in all phases were approximately 4 percentage points higher in the fosaprepitant group compared with the aprepitant group. Fosaprepitant was generally well-tolerated; common AEs were similar to oral aprepitant.

CONCLUSIONS

IV fosaprepitant is as safe and effective as oral aprepitant in the Indian subpopulation and offers an alternative to the oral formulation.

History of trace gases in presolar diamonds inferred from ion-implantation experiments

Diamond grains are the most abundant presolar grains found in primitive meteorites. They formed before the Solar System, and therefore provide a record of nuclear and chemical processes in stars and in the interstellar medium. Their origins are inferred from the unusual isotopic compositions of trace elements-mainly xenon-which suggest that they came from supernovae. But the exact nature of the sources has been enigmatic, as has the method by which noble gases were incorporated into the grains. One observation is that different isotopic components are released at different temperatures when the grains are heated, and it has been suggested that these components have different origins. Here we report results of a laboratory study that shows that ion implantation (previously suggested on other grounds) is a viable mechanism for trapping noble gases. Moreover, we find that ion implantation of a single isotopic composition can produce both low- and high-temperature release peaks from the same grains. We conclude that both isotopically normal and anomalous gases may have been implanted by multiple events separated in space and/or time, with thermal processing producing an apparent enrichment of the anomalous component in the high-temperature release peak. The previous assumption that the low- and high-temperature components were not correlated may therefore have led to an overestimate of the abundance of anomalous argon and krypton, while obscuring an enhancement of the light-in addition to the heavy-krypton isotopes.