Anti-COVID-19 drug screening: Frontier concepts and core technologies

SARS-CoV-2: An Updated Review Highlighting Its Evolution and Treatments

Since the SARS-CoV-2 outbreak, pharmaceutical companies and researchers worldwide have worked hard to develop vaccines and drugs to end the SARS-CoV-2 pandemic. The potential pathogen responsible for Coronavirus Disease 2019 (COVID-19), SARS-CoV-2, belongs to a novel lineage of beta coronaviruses in the subgenus arbovirus. Antiviral drugs, convalescent plasma, monoclonal antibodies, and vaccines are effective treatments for SARS-CoV-2 and are beneficial in preventing infection. Numerous studies have already been conducted using the genome sequence of SARS-CoV-2 in comparison with that of other SARS-like viruses, and numerous treatments/prevention measures are currently undergoing or have already undergone clinical trials. We summarize these studies in depth in the hopes of highlighting some key details that will help us to better understand the viral origin, epidemiology, and treatments of the virus.

Preclinical Efficacy and Safety Studies of Formulation SSV-003, a Potent Anti-Viral Herbal Formulation

Background

Recent viral pandemics have challenged the global scientific community to immediately develop new therapies. The fastest approach to develop these is to explore natural products for their efficacies and repurposing of already approved molecules. Keeping global emergency in view, researchers at Shreepad Shree Vallabh SSV Phytopharmaceuticals developed the Curvic^TM (SSV-003) formulation, comprising of curcumin, vitamin C, vitamin K2-7, selenomethionine and Zinc.

Methods

Researchers have systematically studied the SSV-003 formulation for its in vitro efficacy against influenza A virus (H1N1) (ATCC^® VR-219™) and human beta coronavirus (ATCC^® VR1558™) using MDCK & HCT-8 cell lines, respectively, in vivo efficacy studies of SSV-003 on influenza A virus infected Balb/c mice, and acute toxicity studies as per OECD guidelines.

Results

Formulation SSV-003 showed potent antiviral activities against both the selected virus strains. Its IC₅₀ was significantly lessthan ribavirin against influenza A-H1N1-VR219, with no cytopathic effect. SSV-003 showed IC₅₀ of 2.26 µg/mL against human beta coronavirus, which was near to the IC₅₀ of ribavirin (2.25 µg/mL) and was less than remedisivir (6.23 µg/mL) with no cytopathic effect. In-vivo studies in an influenza A virus infected mice model showed a significantly higher TCID50 value in the infected control group as compared to test groups. Animals treated with SSV-003 showed a dose dependent decrease in TCID50. Formulation SSV-003 at the dose of 500, 1,000, and 1,500 mg/kg body weight showed 85.9%, 94.6%, and 95.1% decreases in infection as compared to the infected control group. Dose-dependent significant increases in CD4+, CD8+ counts, IgG and IgM levels were observed in SSV-003 treated groups as compared to the infected control group and remedisivir treated group. In the acute oral toxicity study, no mortality or morbidity was observed.

Conclusion

The data from these preclinical studies provide strong evidence of potent and safe antiviral and immunomodulatory activity of SSV-003.

Simple rapid in vitro screening method for SARS-CoV-2 anti-virals that identifies potential cytomorbidity-associated false positives

Background

The international SARS-CoV-2 pandemic has resulted in an urgent need to identify new anti-viral drugs for treatment of COVID-19. The initial step to identifying potential candidates usually involves in vitro screening that includes standard cytotoxicity controls. Under-appreciated is that viable, but stressed or otherwise compromised cells, can also have a reduced capacity to replicate virus. A refinement proposed herein for in vitro drug screening thus includes a simple growth assay to identify drug concentrations that cause cellular stress or “cytomorbidity”, as distinct from cytotoxicity or loss of viability.

Methods

A simple rapid bioassay is presented for antiviral drug screening using Vero E6 cells and inhibition of SARS-CoV-2 induced cytopathic effects (CPE) measured using crystal violet staining. We use high cell density for cytotoxicity assays, and low cell density for cytomorbidity assays.

Results

The assay clearly illustrated the anti-viral activity of remdesivir, a drug known to inhibit SARS-CoV-2 replication. In contrast, nitazoxanide, oleuropein, cyclosporine A and ribavirin all showed no ability to inhibit SARS-CoV-2 CPE. Hydroxychloroquine, cyclohexamide, didemnin B, γ-mangostin and linoleic acid were all able to inhibit viral CPE at concentrations that did not induce cytotoxicity. However, these drugs inhibited CPE at concentrations that induced cytomorbidity, indicating non-specific anti-viral activity.

Conclusions

We describe the methodology for a simple in vitro drug screening assay that identifies potential anti-viral drugs via their ability to inhibit SARS-CoV-2-induced CPE. The additional growth assay illustrated how several drugs display anti-viral activity at concentrations that induce cytomorbidity. For instance, hydroxychloroquine showed anti-viral activity at concentrations that slow cell growth, arguing that its purported in vitro anti-viral activity arises from non-specific impairment of cellular activities. The cytomorbidity assay can therefore rapidly exclude potential false positives.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12985-021-01587-z.

Research progress of traditional Chinese medicine against COVID-19

BACKGROUND

Currently, the number of confirmed cases and deaths of COVID-19 worldwide continues to rise, receiving great concern from the international community. However, there is no specific and widely accepted effective vaccines. The experience in controlling the outbreak in China has proven the effectiveness of traditional Chinese medicine (TCM).

OBJECTIVES

This review aims to evaluate the role of TCM in COVID-19 treatment, hoping to provide references for prevention and control of global pandemic.

DATA SOURCES

China National Knowledge Infrastructure, Web of Science, Baidu Scholar, ScienceDirect, Elsevier and PubMed were used to search literatures published from December 2019 to December 2020 by entering the keywords "Traditional Chinese medicine", "COVID-19″, "Severe acute respiratory syndrome coronavirus 2″, "Pathogenesis", "Syndrome differentiation", "Prescriptions" and their combinations. Hence, we have performed an extensive review of research articles, reviews and primary scientific studies to identify TCM against COVID-19.

RESULTS

Among clinical treatments of COVID-19, several TCM prescriptions and characteristic therapies have been effectively suggested, the underlying mechanisms of which are mainly involved in antiviral, anti-inflammatory, immunomodulatory and organ-protective effects of multi-components acting on multi-targets at multi-pathways.

CONCLUSIONS

This review may provide meaningful and feasible information that can be considered for the treatment of COVID-19 pandemic globally.

Main Chemotypes of SARS-CoV-2 Reproduction Inhibitors

The COVID-19 pandemic has forced scientists all over the world to focus their effort on searching for targeted drugs for coronavirus chemotherapy. The present review is an attempt to systematize low-molecular-weight compounds, including well-known pharmaceuticals and natural substances that have exhibited high anti-coronavirus activity, not in terms of action on their targets, but in terms of their structural type.

Drug supply situation in Rwanda during COVID-19: issues, efforts and challenges

COVID-19 is a threat to health systems around the world and Rwanda is not an exception. The impact of the pandemic is far-reaching and access to health commodities is not spared. Proper drug supply is critical for a robust healthcare system. It determines the extent at which the population are likely to have access to essential medicines and treatments. In Rwanda, the pharmaceutical sector heavily relies on imports. With the emergence of COVID-19 pandemic, the drug supply system was interrupted leaving many stores from small local pharmacies to the big medical stores running out of stock. The reasons were limited importation of goods from abroad, and the panic buying practice among the customers and some institutions when responding to the pandemic. Drug and medicines accessibility, availability and affordability should be the core of any drug management policy. It is with no doubt that, Rwanda has made a tremendous work to mitigate the effect of COVID-19 on the country's drug supply; however, efforts are still needed to invest in local pharmaceutical production as a way to minimize import expenses in the country. Good policy on drug importation, production and distribution should be enforced to avoid any drug shortage that may be encountered in the Rwandan drug market.

Laboratory-Based Resources for COVID-19 Diagnostics: Traditional Tools and Novel Technologies. A Perspective of Personalized Medicine

The coronavirus infection 2019 (COVID-19) pandemic, caused by the highly contagious SARS-CoV-2 virus, has provoked a global healthcare and economic crisis. The control over the spread of the disease requires an efficient and scalable laboratory-based strategy for testing the population based on multiple platforms to provide rapid and accurate diagnosis. With the onset of the pandemic, the reverse transcription polymerase chain reaction (RT-PCR) method has become a standard diagnostic tool, which has received wide clinical use. In large-scale and repeated examinations, these tests can identify infected patients with COVID-19, with their accuracy, however, dependent on many factors, while the entire process takes up to 6–8 h. Here we also describe a number of serological systems for detecting antibodies against SARS-CoV-2. These are used to assess the level of population immunity in various categories of people, as well as for retrospective diagnosis of asymptomatic and mild COVID-19 in patients. However, the widespread use of traditional diagnostic tools in the context of the rapid spread of COVID-19 is hampered by a number of limitations. Therefore, the sharp increase in the number of patients with COVID-19 necessitates creation of new rapid, inexpensive, sensitive, and specific tests. In this regard, we focus on new laboratory technologies such as loop mediated isothermal amplification (LAMP) and lateral flow immunoassay (LFIA), which have proven to work well in the COVID-19 diagnostics and can become a worthy alternative to traditional laboratory-based diagnostics resources. To cope with the COVID-19 pandemic, the healthcare system requires a combination of various types of laboratory diagnostic testing techniques, whodse sensitivity and specificity increases with the progress in the SARS-CoV-2 research. The testing strategy should be designed in such a way to provide, depending on the timing of examination and the severity of the infection in patients, large-scale and repeated examinations based on the principle: screening–monitoring–control. The search and development of new methods for rapid diagnostics of COVID-19 in laboratory, based on new analytical platforms, is still a highly important and urgent healthcare issue. In the final part of the review, special emphasis is made on the relevance of the concept of personalized medicine to combat the COVID-19 pandemic in the light of the recent studies carried out to identify the causes of variation in individual susceptibility to SARS-CoV-2 and increase the efficiency and cost-effectiveness of treatment.