DHFR Inhibitors Display a Pleiotropic Anti-Viral Activity against SARS-CoV-2: Insights into the Mechanisms of Action.

During the COVID-19 pandemic, drug repurposing represented an effective strategy to obtain quick answers to medical emergencies. Based on previous data on methotrexate (MTX), we evaluated the anti-viral activity of several DHFR inhibitors in two cell lines. We observed that this class of compounds showed a significant influence on the virus-induced cytopathic effect (CPE) partly attributed to the intrinsic anti-metabolic activity of these drugs, but also to a specific anti-viral function. To elucidate the molecular mechanisms, we took advantage of our EXSCALATE platform for in-silico molecular modelling and further validated the influence of these inhibitors on nsp13 and viral entry. Interestingly, pralatrexate and trimetrexate showed superior effects in counteracting the viral infection compared to other DHFR inhibitors. Our results indicate that their higher activity is due to their polypharmacological and pleiotropic profile. These compounds can thus potentially give a clinical advantage in the management of SARS-CoV-2 infection in patients already treated with this class of drugs.

The Anti-Viral Activity of Stem Cells: A Rational Explanation for their Use in Clinical Application.

It is well established the importance of stem cells (SCs) in tissue growth, regeneration and repair, given their ability to self-renew and differentiate into mature cells. Stem cells are present in all individuals and are potentially active to the end of life. However, less is known about their unique function within the immune system as immune regulators and their important task in viral protection. Antiviral resistance is a common mechanism in all cells though stem cells utilize an antiviral RNA interference (RNAi) mechanism, while adult cells react by using the interferondependent repression pathway via interferon-associated protein-based response to induce an antiviral response. Therefore, the idea behind this review is to highlight the mechanisms of viral evasion of host defense, which would then allow us to highlight the rationale use of autologous stem cells and their biochemical and immunological ability to reset the subverted immune responses. Recently, scientists have highlighted their use in the field of immune-therapy, establishing the possibilities of using them outside the conventional protocol with the advancement in manipulating these cells in such a way that specific body activity can be restored. This paper describes the remarkable SCs profile and discusses some ideas regarding their promising use in vivo.

The Anti-Histamine Azelastine, Identified by Computational Drug Repurposing, Inhibits Infection by Major Variants of SARS-CoV-2 in Cell Cultures and Reconstituted Human Nasal Tissue.

Background and purpose: The COVID-19 pandemic continues to pose challenges, especially with the emergence of new SARS-CoV-2 variants that are associated with higher infectivity and/or compromised protection afforded by the current vaccines. There is a high demand for additional preventive and therapeutic strategies effective against this changing virus. Repurposing of approved or clinically tested drugs can provide an immediate solution. Experimental Approach: We applied a novel computational approach to search among approved and commercially available drugs. Antiviral activity of a predicted drug, azelastine, was tested in vitro in SARS-CoV-2 infection assays with Vero E6 cells, Vero cells stably overexpressing the human TMPRSS2 and ACE2 proteins as well as on reconstituted human nasal tissue using the predominant variant circulating in Europe in summer 2020, B.1.177 (D614G variant), and its emerging variants of concern; B.1.1.7 (alpha), B.1.351 (beta) and B.1.617.2 (delta) variants. The effect of azelastine on viral replication was assessed by quantification of viral genomes by droplet digital PCR or qPCR. Key results: The computational approach identified major drug families, such as anti-infective, anti-inflammatory, anti-hypertensive, antihistamine, and neuroactive drugs. Based on its attractive safety profile and availability in nasal formulation, azelastine, a histamine 1 receptor-blocker was selected for experimental testing. Azelastine reduced the virus-induced cytopathic effect and SARS-CoV-2 copy numbers both in preventive and treatment settings upon infection of Vero cells with an EC50 of 2.2-6.5 µM. Comparable potency was observed with the alpha, beta and delta variants. Furthermore, five-fold dilution (containing 0.02% azelastine) of the commercially available nasal spray formulation was highly potent in inhibiting viral propagation in reconstituted human nasal tissue. Conclusion and Implications: Azelastine, an antihistamine available as nasal sprays developed against allergic rhinitis may be considered as a topical prevention or treatment of nasal colonization by SARS-CoV-2. A Phase 2 efficacy indicator study with azelastine-containing nasal spray that was designed based on the findings reported here has been concluded recently, confirming accelerated viral clearance in SARS-CoV-2 positive subjects.

Green Tea Catechins Against COVID-19: Lower COVID-19 Morbidity and Mortality in Countries with Higher per capita Green Tea Consumption

Background: Several vaccines are currently validated for COVID-19 prevention and mass vaccination has already been started in many countries. Nevertheless, it is likely that the development of an efficient therapy that reduces COVID-19 severity/mortality would be still impor-tant for a rather prolonged time, in particular, due to new variants of SARS-CoV-2. Several lines of emerging evidence suggest that green tea catechins such as epigallocatechin-3-gallate have direct anti-viral activity and affect factors associated with COVID-19 severity. Objective(s): Considering that green tea catechins are major constituents of green tea, it may be expected that countries with higher per capita green tea consumption would be less affected by COVID-19. This study assessed this possibility. Method(s): Among countries with a population of at least 3 million (n=134), those with relatively high (above 150 g) per capita green tea consumption have been identified (n=21);(ii) normalized to population values of COVID-19 cases (morbidity) and deaths (mortality) for groups of countries with high and low per capita green tea consumption were compared. Result(s): Striking differences in COVID-19 morbidity and mortality between groups of countries with 'high' and 'low' green tea consumption were found. The differences were still observed after the adjustment for the onset of the disease. An analysis using the multiple linear regression approach suggests that the associations are present at the level of individual countries. Conclusion(s): Results of this study, taken together with emerging pharmacological evidence, suggest that green tea catechins can give valuable clues for the treatment/amelioration of COVID-19.Copyright © 2022 Bentham Science Publishers.

The Mechanisms of Zinc Action as a Potent Anti-Viral Agent: The Clinical Therapeutic Implication in COVID-19.

The pandemic of COVID-19 was caused by a novel coronavirus termed as SARS-CoV2 and is still ongoing with high morbidity and mortality rates in the whole world. The pathogenesis of COVID-19 is highly linked with over-active immune and inflammatory responses, leading to activated cytokine storm, which contribute to ARDS with worsen outcome. Currently, there is no effective therapeutic drug for the treatment of COVID-19. Zinc is known to act as an immune modulator, which plays an important role in immune defense system. Recently, zinc has been widely considered as an anti-inflammatory and anti-oxidant agent. Accumulating numbers of studies have revealed that zinc plays an important role in antiviral immunity in several viral infections. Several early clinical trials clearly indicate that zinc treatment remarkably decreased the severity of the upper respiratory infection of rhinovirus in humans. Currently, zinc has been used for the therapeutic intervention of COVID-19 in many different clinical trials. Several clinical studies reveal that zinc treatment using a combination of HCQ and zinc pronouncedly reduced symptom score and the rates of hospital admission and mortality in COVID-19 patients. These data support that zinc might act as an anti-viral agent in the addition to its anti-inflammatory and anti-oxidant properties for the adjuvant therapeutic intervention of COVID-19.

Synthesis, Antiviral, and Antibacterial Activity of the Glycyrrhizic Acid and Glycyrrhetinic Acid Derivatives.

Glycyrrhizic acid and its primary metabolite glycyrrhetinic acid, are the main active ingredients in the licorice roots (glycyrrhiza species), which are widely used in several countries of the world, especially in east asian countries (China, Japan). These ingredients and their derivatives play an important role in treating many diseases, especially infectious diseases such as COVID-19 and hepatic infections. This review aims to summarize the different ways of synthesising the amide derivatives of glycyrrhizic acid and the main ways to synthesize the glycyrrhitinic acid derivatives. Also, to determine the main biological and pharmacological activity for these compounds from the previous studies to provide essential data to researchers for future studies. Supplementary Information: The online version contains supplementary material available at 10.1134/S1068162022050132.

Ginseng, a promising choice for SARS-COV-2: A mini review.

The current Covid-19 pandemic has changed the entire world and bought so many unprecedented challenges to the scientific community. More than 5 million people died due to the SARS-COV-2 outbreak. For many thousands of years, ginseng, the traditional herb has been used for various infectious diseases by traditional healers. Ginseng showed promising antiviral effects by modulating both natural and acquired immunity. Ginseng might be used as a potential therapeutic agent to prevent SARS-CoV-2 infection along with the vaccine. In this current review, we offer an alternative approach for SARS-COV-2 prevention during this unprecedented pandemic.

Investigative study into whether an insect repellent has virucidal activity against SARS-CoV-2.

A small-scale study with Mosi-guard Natural spray, an insect repellent containing Citriodiol, was performed to determine if it has virucidal activity against SARS-CoV-2. A liquid test examined the activity of the insect repellent and the individual components for virucidal activity. A surface contact test looked at the activity of the insect repellent when impregnated on a latex surface as a synthetic skin for potential topical prophylactic application. Both Mosi-guard Natural spray and Citriodiol, as well as other components of the repellent, had virucidal activity in the liquid contact test. On a latex surface used to simulate treated skin, the titre of SARS-CoV-2 was less over time on the Mosi-guard Natural-treated surface but virus was still recovered.

Soybean-associated endophytic fungi as potential source for anti-COVID-19 metabolites supported by docking analysis.

AIMS: To identify the metabolites produced by the endophytic fungus, Aspergillus terreus and to explore the anti-viral activity of the identified metabolites against the pandemic disease COVID-19 in-silico. METHODS AND RESULTS: Herein, we reported the isolation of A. terreus, the endophytic fungus associated with soybean roots, which is then subcultured using OSMAC approach in five different culture media. Analytical analysis of media ethylacetate extracts using liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS) was carried out. Furthermore, the obtained LC-MS data were statistically processed with MetaboAnalyst 4.0. Molecular docking studies were performed for the dereplicated metabolites against COVID-19 main protease (Mpro ). Metabolomic profiling revealed the presence of 18 compounds belonging to different chemical classes. Quinones, polyketides and isocoumarins were the most abundant classes. Multivariate analysis revealed that potato dextrose broth and modified potato dextrose broth are the optimal media for metabolites production. Molecular docking studies declared that the metabolites, Aspergillide B1 and 3a-Hydroxy-3, 5-dihydromonacolin L showed the highest binding energy scores towards COVID-19 main protease (Mpro ) (-9·473) and (-9·386), respectively, and they interact strongly with the catalytic dyad (His41 and Cys145) amino acid residues of Mpro . CONCLUSIONS: A combination of metabolomics and in-silico approaches have allowed a shorter route to search for anti-COVID-19 natural products in a shorter time. The dereplicated metabolites, aspergillide B1 and 3α-Hydroxy-3, 5-dihydromonacolin L were found to be potent anti-COVID-19 drug candidates in the molecular docking study. SIGNIFICANCE AND IMPACT OF THE STUDY: This study revealed that the endophytic fungus, A. terreus can be considered as a potential source of natural bioactive products. In addition to, the possibility of developing the metabolites, aspergillide B1 and 3α-Hydroxy-3, 5-dihydromonacolin L to be used as phytopharmaceuticals for the management of COVID-19.

Novel cyclohexanone compound as a potential ligand against SARS-CoV-2 main-protease.

No commercially available drug candidate has yet been devised which is unique to and not repurposed against SARS-CoV-2 and has high efficacy or safe toxicity profile or both. Taking curcumin as a reference compound, we identified a new commercially available cyclohexanone compound, ZINC07333416 with binding energy (-8.72 kcal/mol) better than that of popularly devised anti-Covid-19 drugs like viral protease inhibitor Lopinavir, nucleoside analogue Remdesivir and the repurposed drug hydroxychloroquine when targeted to the active-site of SARS-CoV-2 Main protease (Mpro) through docking studies. The ligand ZINC07333416 exhibits crucial interactions with major active site residues of SARS-CoV-2 Mpro viz. Cys145 and His41 involving in the protease activity; as well as GLU-166 and ASN-142 which plays the pivotal role in the protein-dimerization. The protein-ligand stable interaction was further confirmed with molecular dynamics simulation (MDS) studies. Based on virtual assessment, ZINC07333416 also have significant values in terms of medicinal chemistry, pharmacokinetics, synthetic accessibility and anti-viral activity that encourage its experimental applications against COVID-19.

Is hesperidin essential for prophylaxis and treatment of COVID-19 Infection?

SARS-CoV-2 or COVID-19 is representing the major global burden that implicated more than 4.7 million infected cases and 310 thousand deaths worldwide in less than 6 months. The prevalence of this pandemic disease is expected to rise every day. The challenge is to control its rapid spread meanwhile looking for a specific treatment to improve patient outcomes. Hesperidin is a classical herbal medicine used worldwide for a long time with an excellent safety profile. Hesperidin is a well-known herbal medication used as an antioxidant and anti-inflammatory agent. Available shreds of evidence support the promising use of hesperidin in prophylaxis and treatment of COVID 19. Herein, we discuss the possible prophylactic and treatment mechanisms of hesperidin based on previous and recent findings. Hesperidin can block coronavirus from entering host cells through ACE2 receptors which can prevent the infection. Anti-viral activity of hesperidin might constitute a treatment option for COVID-19 through improving host cellular immunity against infection and its good anti-inflammatory activity may help in controlling cytokine storm. Hesperidin mixture with diosmin co-administrated with heparin protect against venous thromboembolism which may prevent disease progression. Based on that, hesperidin might be used as a meaningful prophylactic agent and a promising adjuvant treatment option against SARS-CoV-2 infection.