Chemistry Related to the Catalytic Cycle of the Antioxidant Ebselen.

The antioxidant drug ebselen has been widely studied in both laboratories and in clinical trials. The catalytic mechanism by which it destroys hydrogen peroxide via reduction with glutathione or other thiols is complex and has been the subject of considerable debate. During reinvestigations of several key steps, we found that the seleninamide that comprises the first oxidation product of ebselen underwent facile reversible methanolysis to an unstable seleninate ester and two dimeric products. In its reaction with benzyl alcohol, the seleninamide produced a benzyl ester that reacted readily by selenoxide elimination, with formation of benzaldehyde. Oxidation of ebselen seleninic acid did not afford a selenonium seleninate salt as previously observed with benzene seleninic acid, but instead generated a mixture of the seleninic and selenonic acids. Thiolysis of ebselen with benzyl thiol was faster than oxidation by ca. an order of magnitude and produced a stable selenenyl sulfide. When glutathione was employed, the product rapidly disproportionated to glutathione disulfide and ebselen diselenide. Oxidation of the S-benzyl selenenyl sulfide, or thiolysis of the seleninamide with benzyl thiol, afforded a transient thiolseleninate that also readily underwent selenoxide elimination. The S-benzyl derivative disproportionated readily when catalyzed by the simultaneous presence of both the thiol and triethylamine. The phenylthio analogue disproportionated when exposed to ambient or UV (360 nm) light by a proposed radical mechanism. These observations provide additional insight into several reactions and intermediates related to ebselen.

Montelukast as a potential treatment for COVID-19.

INTRODUCTION: Montelukast is a leukotriene inhibitor that is widely used to treat chronic asthma and allergic rhinitis. The drug interferes with molecular signaling pathways produced by leukotrienes in a variety of cells and tissues throughout the human body that lead to tightening of airway muscles, production of aberrant pulmonary fluid (airway edema), and in some cases, pulmonary inflammation. AREAS COVERED: Montelukast has also been noted to have anti-inflammatory properties, suggesting it may have a role in the treatment of coronavirus disease 2019 (COVID-19), the disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which has been noted to induce misfiring of the immune system in some patients. A literature search of PubMed was performed to identify all relevant studies of montelukast and SARS-CoV-2 through 27 January 2023. EXPERT OPINION: Montelukast has been the subject of small studies of SARS-CoV-2 and will be included in a large, randomized, double-blind, placebo-controlled study of outpatients with COVID-19 sponsored by the United States National Institutes of Health known as Accelerating COVID-19 Therapeutic Interventions and Vaccines-6. This paper reviews what is known about montelukast, an inexpensive, well-tolerated, and widely available medication, and examines the rationale for using this drug to potentially treat patients with COVID-19.

Volatile sulfide compounds and oral microorganisms on the inner surface of masks in individuals with halitosis during COVID-19 pandemic.

Mask-wearing is still recommended owing to the continuing impact of the COVID-19 pandemic. Within the closed chamber created by the mask, people are increasingly self-aware of their oral malodor. In this prospective and cross-sectional study, we aimed to measure volatile sulfide compound (VSC) levels in patients with halitosis and investigate the oral microbiome profile on the inner surface of their KF94 masks. We also investigated which oral microbiota increases VSC levels and whether the oral microbiomes of oral saliva and mask are correlated. A total of 50 subjects (41 women, average age 38.12 ± 12.58 years old) were included in the study, 25 healthy subjects and 25 patients with halitosis who wore masks for more than 3 h. The dominant bacterial species, bacterial profile, and Shannon diversity index of whole unstimulated saliva and the inner surface of the mask were investigated. The bacterial 16S ribosomal RNA genes of the major oral bacterial species were analyzed using real-time PCR. Gas chromatography was used to measure hydrogen sulfide (H2S) and methyl mercaptan (CH3SH), which are representative VSCs. The total bacterial DNA copy number was significantly higher in the saliva sample than in the mask sample (p < 0.001), and the average value was 276 times greater. Shannon diversity index was also significantly higher in saliva than in the inner surface of the mask (2.62 ± 0.81 vs. 1.15 ± 1.52, p < 0.001). The most common Gram-negative and Gram-positive species in the masks were Porphyromonas gingivalis (Pg) and Lactobacillus casei (Lc), respectively. The bacterial species with significant positive correlations between saliva and mask samples were Prevotella intermedia (Pi) (r = 0.324, p = 0.022), Eikenella corrodens (r = 0.309, p = 0.029), Lc (r = 0.293, p = 0.039), and Parvimonas micra (Pm) (r = 0.366, p = 0.009). The mean value of CH3SH was significantly higher in the halitosis group than in the non-halitosis group (17.84 ± 29.00 vs. 3.84 ± 10.57 ppb, p = 0.031). In the halitosis group, the DNA copy numbers and VSC levels showed highly positive correlation coefficients in the order Pg, Treponema denticola (Td), Tannerella forsythia (Tf), Pi, and Prevotella nigrescens (Pn) (all p < 0.05). Regarding bacterial profiles of the mask, Td was strongly correlated with CH3SH (r = 0.414, p = 0.040) and total VSCs (r = 0.374, p = 0.033) only in halitosis group. Mask-wearing time was strongly correlated with total VSCs, H2S, and CH3SH (all r > 0.8, p < 0.001). Oral bacteria, whose association with halitosis has been identified, increased VSC levels in mask-wearing subjects during the COVID-19 pandemic, particularly the number of Gram-negative anaerobes such as Pg and Td. Mask-wearing time was a major factor in increasing VSC levels. The study results suggest that people with halitosis could control these Gram-negative bacteria by improving oral hygiene and regularly changing masks.

Photocatalytic degradation of COVID-19 related drug arbidol hydrochloride by Ti3C2 MXene/supramolecular g-C3N4 Schottky junction photocatalyst.

Because of the current COVID-19 outbreak all over the world, the problem of antiviral drugs entering water has become increasingly serious. Arbidol hydrochloride (ABLH) is one of the most widely used drugs against COVID-19, which has been detected in sewage treatment plant sediments after the COVID-19 outbreak. However, there has been no report on the degradation of ABLH. In order to remove ABLH we prepared a novel photocatalyst composed of Ti3C2 MXene and supramolecular g-C3N4 (TiC/SCN) via a simple method. The properties of the material were studied by a series of characterizations (SEM, TEM, EDS, XRD, FTIR, UV-vis, DRS, XPS, TPC, PL, EIS and UPS), indicating the successful preparation of TiC/SCN. Results show that 99% of ABLH was removed within 150 min under visible light illumination by the 0.5TiC/SCN (containing 0.5% of TiC). The performance of 0.5TiC/SCN was about 2.66 times that of SCN resulting from the formation of Schottky junction. Furthermore, under real sunlight illumination, 99.2% of ABLH could be removed by 0.5TiC/SCN within 120 min, which was better than that of commercial P25 TiO2. The pH, anions (NO3- and SO42-) and dissolved organic matter (fulvic acid) could significantly affect the ABLH degradation. Moreover, three possible degradation pathways of ABLH were proposed, and the toxicities of the corresponding by-products were less toxic than ABLH. Meanwhile, findings showed that the superoxide radicals played a major role in the photocatalytic degradation of ABLH by 0.5TiC/SCN. This study provides a well understanding of the mechanism of ABLH degradation and provides a valuable reference for the treatment of ABLH in water.

Reactive sulfur species and their significance in health and disease.

Reactive sulfur species (RSS) have been recognized in the last two decades as very important molecules in redox regulation. They are involved in metabolic processes and, in this way, they are responsible for maintenance of health. This review summarizes current information about the essential biological RSS, including H2S, low molecular weight persulfides, protein persulfides as well as organic and inorganic polysulfides, their synthesis, catabolism and chemical reactivity. Moreover, the role of RSS disturbances in various pathologies including vascular diseases, chronic kidney diseases, diabetes mellitus Type 2, neurological diseases, obesity, chronic obstructive pulmonary disease and in the most current problem of COVID-19 is presented. The significance of RSS in aging is also mentioned. Finally, the possibilities of using the precursors of various forms of RSS for therapeutic purposes are discussed.

The effectiveness of gabapentin and gabapentin/montelukast combination compared with dextromethorphan in the improvement of COVID-19- related cough: A randomized, controlled clinical trial.

INTRODUCTION: Cough is one of the most common presenting symptoms of COVID-19, which can persist for weeks or months. OBJECTIVE: The goal of this study was to evaluate the effectiveness of gabapentin (GBT) alone and in combination with montelukast (MTL) for improving cough. METHODS: In this open-label randomized controlled clinical trial, eligible cases were patients hospitalized with moderate to severe COVID-19 who had cough with a Breathlessness, Cough, and Sputum Scale (BCSS) score of at least 2 based on its cough subscale. The participants were randomly assigned to three groups including two experimental groups and one control group. The first and second experimental groups received GBT and GBT/MTL, respectively, whereas the control group received dextromethorphan (DXM). Treatment duration was 5 days in all groups. Before and after the interventions, the severity of cough was evaluated using BCSS scale and Visual Analog Scale (VAS). RESULTS: A total of 180 patients were included; GPT, GPT/MTL, and DXM consisted of 76, 51, and 53 patients, respectively. There was no significant difference between the three groups in terms of age, gender, and comorbidities (P > 0.05). Regarding BCSS and VAS scores, there was significant reduction from the baseline values in all groups (P < 0.0001), with the change rate being significantly higher in DXM group. The amount of reduction of BCSS in the GPT/MTL group was significantly more than the GPT group, whereas there was no significant difference between the two groups regarding VAS score. Although the duration of hospitalization differed between the groups with the GPT/MTL group having the shortest duration, the difference was statistically significant only between the GPT and GPT/MTL groups (P < 0.0001). CONCLUSION: GPT, both alone and in combination with MTL, improves cough frequency and severity in hospitalized patients with COVID-19, with the combination being more efficacious. This regimen may be useful in patients who cannot tolerate opioids.

Discovery of honokiol thioethers containing 1,3,4-oxadiazole moieties as potential α-glucosidase and SARS-CoV-2 entry inhibitors.

Honokiol, isolated from a traditional Chinese medicine (TCM) Magnolia officinalis, is a biphenolic compound with several biological activities. To improve and broaden its biological activity, herein, two series of honokiol thioethers bearing 1,3,4-oxadiazole moieties were prepared and assessed for their α-glucosidase and SARS-CoV-2 entry inhibitory activities. Among all the honokiol thioethers, compound 7l exhibited the strongest α-glucosidase inhibitory effect with an IC50 value of 18.9 ± 2.3 µM, which was superior to the reference drug acarbose (IC50 = 24.4 ± 0.3 µM). Some interesting results of structure-activity relationships (SARs) have also been discussed. Enzyme kinetic study demonstrated that 7l was a noncompetitive α-glucosidase inhibitor, which was further supported by the results of molecular docking. Moreover, honokiol thioethers 7e, 9a, 9e, and 9r exhibited potent antiviral activity against SARS-CoV-2 pseudovirus entering into HEK-293 T-ACE2h. Especially 9a displayed the strongest inhibitory activity against SARS-CoV-2 pseudovirus entry with an IC50 value of 16.96 ± 2.45 µM, which was lower than the positive control Evans blue (21.98 ± 1.98 µM). Biolayer interferometry (BLI) binding and docking studies suggested that 9a and 9r may effectively block the binding of SARS-CoV-2 to the host ACE2 receptor through dual recognition of SARS-CoV-2 spike RBD and human ACE2. Additionally, the potent honokiol thioethers 7l, 9a, and 9r displayed relatively no cytotoxicity to normal cells (LO2). These findings will provide a theoretical basis for the discovery of honokiol derivatives as potential both α-glucosidase and SARS-CoV-2 entry inhibitors.

Addition of a nutraceutical to montelukast or inhaled steroid in the treatment of wheezing during COVID-19 pandemic: a multicenter, open-label, randomized controlled trial.

Background and aim Recurrent wheezing is often triggered by viral respiratory infections. The aims of our study were: i) to evaluate whether the addition of a nutraceutical (Leucodif®), could improve the efficacy of montelukast or inhaled steroids (ICS) compared to the single treatment; ii) to verify whether a treatment is more effective than another. Our study was biased by the COVID-19 pandemic, which resulted in a lockdown of almost two months in Italy. Methods The multicenter, open-label study enrolled 84 children aged 2-6 years diagnosed with recurrent wheezing and randomized them into four treatment arms for three months: ICS treatment; ii) montelukast; iii) montelukast + Leucodif; iv) ICS + Leucodif. Children were assessed at baseline and after one, two, and three months of treatment using the TRACK score for both the caregiver and the physician. Results Out of the 84 patients, 18 patients received ICS therapy, 22 patients ICS + Leucodif, 24 patients montelukast, and 20 patients montelukast + Leucodif. All four treatments resulted in a significant reduction in symptoms with no differences among the various groups. Conclusions Our study demonstrates that montelukast therapy appears to be equally effective as ICS therapy and that the addition of the nutraceutical Leucodif does not appear to improve the treatment outcome. However, in our opinion our study was strongly influenced and biased by the lockdown due to the COVID-19 pandemic, which inherently resulted in reduced exposure to the viruses that commonly cause respiratory infections in children.

Montelukast Inhibits HCoV-OC43 Infection as a Viral Inactivator.

Coronaviruses (CoVs) consist of a large group of RNA viruses causing various diseases in humans and in lots of animals. Human coronavirus (HCoV) OC43, the prototype of beta-coronavirus discovered in the 1960s, has been circulating in humans for long time, and infection with other emerging strains of beta-coronavirus (SARS-CoV, SARS-CoV-2, and MERS-CoV) can lead to severe illness and death. In this study, we found that montelukast, a leukotriene receptor antagonist, potently inhibited the infection of HCoV-OC43 in distinct cells in a dose- and time- dependent manner. Additionally, the results showed that montelukast induced release of HCoV-OC43 genomic RNA by disrupting the integrity of the viral lipid membrane, and irreversibly inhibited viral infection. Considering the similarity among HCoV-OC43, MERS-CoV, and SARS-CoV-2, it suggests that montelukast may be a potential candidate for the treatment of human beta-coronavirus infection.

Molecular docking-assisted investigation of Pd(II) complexes carrying "SNS" pincer-type pyridine-thioether ligand as potential drug candidates against COVID-19.

The coronavirus disease 2019 (COVID-19) pandemic has posed a threat to public health throughout the world since the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) was discovered in late 2019. Since the beginning of the pandemic, scientists have done a tremendous amount of work in this area. However, among these studies, the investigation of the effect of newly synthesized compounds against coronavirus is rather weak. Examining the newly synthesized compounds with a computer-assisted molecular docking study provides quite an advantage in terms of the estimation and analysis of the biochemical activity and binding affinity of existing synthesized compounds against a biological target in a labor, time, and cost-saving way. In this study, the SNS pincer type 2,6-bis[[(4-methylphenyl)thio]methyl]pyridine ligand(L) (1) and its novel Pd(II) complexes ([Pd(κ2-L)(OAc)2]·3H2O (2) and [Pd(κ2-L)Cl2]·3H2O (3)) were synthesized and characterized by using FT-IR, UV-Vis, NMR, mass and elemental analysis techniques. The synthesized Pd complexes exhibited a square planar structure. The compounds were found to have non-electrolytic behavior. In the meantime, in silico investigations have defined and justified interaction processes between these molecules and Pd(II) at the atomic level. Furthermore, using molecular docking against target proteins of SARS-CoV-2, the efficiency of the SNS pincer type ligand and its Pd (II) complexes produced was studied and discussed for the first time. The experimental data has been supported and illuminated using computational visual methods and molecular docking, and the findings produced indicate compatibility. The binding energy values of the relevant compounds on the four protein model structures of SARS-CoV-2 (Main Protease, Papain-like protease, RdRp without RNA, and RdRp with RNA) are represented. Compound 2 ([Pd(κ2-L)(OAc)2]·3H2O) is the structure that exhibits the highest biochemical activity. According to all of the docking studies, Papain-like protease is the SARS-CoV-2 protein with which the three compounds exhibit mutual interaction. The compound 2 structure, in particular, is the most effective in terms of structural and interaction with the targets, as well as binding orientations.

Effect of montelukast therapy on clinical course, pulmonary function, and mortality in patients with COVID-19.

The inflammatory/anti-inflammatory balance has an important role in the clinical course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (coronavirus disease [COVID-19]) infection, which has affected over 200 million people since it first appeared in China in December 2019. This study aimed to determine the effectiveness of montelukast, which has known anti-inflammatory and bronchodilatory effects, in these patients. The prospective randomized controlled study included 180 patients who were hospitalized in the infectious diseases department of our hospital between May and July 2021 and were diagnosed with the delta variant of SARS-CoV-2 by real-time polymerase chain reaction of nasopharyngeal swabs. The patients were divided into three groups and received only standard treatment according to national guidelines (Group 1) or standard treatment plus 10 mg/day montelukast (Group 2) or 20 mg/day montelukast (Group 3). Laboratory parameters and pulmonary function tests (PFTs) at admission and on Day 5 of treatment were compared. Comparison of laboratory parameters on Day 5 showed that Groups 2 and 3 had significantly lower levels of lactate dehydrogenase, fibrinogen, D-dimer, C-reactive protein, and procalcitonin compared with Group 1 (p = 0.04, 0.002, 0.05, 0.03, and 0.04, respectively). In the comparison between Groups 2 and 3, only fibrinogen was significantly lower in Group 3 (p = 0.02). PFT results did not differ between the groups at admission, while on Day 5, only Group 3 showed significant improvements in forced expiratory volume in 1 s, forced vital capacity, and peak expiratory flow 25-75 compared with admission (p = 0.001 for all). Montelukast may be beneficial in COVID-19 patients to maintain the inflammatory/anti-inflammatory balance, prevent respiratory failure through its bronchodilator activity, and reduce mortality.

PAMAM-calix-dendrimers: Synthesis and Thiacalixarene Conformation Effect on DNA Binding.

A convenient method for the synthesis of the first generation PAMAM dendrimers based on the thiacalix[4]arene has been developed for the first time. Three new PAMAM-calix-dendrimers with the macrocyclic core in cone, partial cone, and 1,3-alternate conformations were obtained with high yields. The interaction of the obtained compounds with salmon sperm DNA resulted in the formation of the associates of the size up to 200 nm, as shown by the UV-Vis spectroscopy, DLS, and TEM. It was demonstrated by the CD method that the structure of the DNA did not undergo significant changes upon binding. The PAMAM-calix-dendrimer based on the macrocycle in cone conformation stabilized DNA and prevented its degradation.

A rare case of drug-induced bradycardia associated with the just low dose use of methylprednisolone in a child with COVID-19.

Methylprednisolone (MP) is usually used to reduce inflammation reaction and tissue damage, which may have a beneficial treatment effect on coronavirus disease 2019 (COVID-19). However, we present the case of a child who manifests significant bradycardia with the use of just low dose MP on the premise of the long-term use of arbidol. Arbidol can affect the activity of CYP3A4, which is also a key metabolic enzyme of MP by competitive inhibition, and which is easy to aggravate the side effects of MP. Therefore, more attention should be paid to bradycardia occurrence in the patient with COVID-19 when MP is considered in COVID-19.

Meta-analysis of arbidol versus lopinavir/ritonavir in the treatment of coronavirus disease 2019.

OBJECTIVES: To systematically evaluate the efficacy and safety of arbidol and lopinavir/ritonavir (LPV/r) in the treatment of coronavirus disease 2019 (COVID-19) using a meta-analysis method. METHODS: The China Knowledge Network, VIP database, WanFang database PubMed database, Embase database, and Cochrane Library were searched for a collection of comparative studies on arbidol and lopinavir/ritonavir in the treatment of COVID-19. Meta-analysis was used to evaluate the efficacy and safety of Arbidol and lopinavir/ritonavir in the treatment of COVID-19. RESULTS: The results of the systematic review indicated that Arbidol had a higher positive-to-negative conversion rate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid on Day 7 (p = 0.03), a higher positive-to-negative conversion rate of SARS-CoV-2 nucleic acid on Day 14 (p = 0.006), a higher improvement rate of chest computed tomography on Day 14 (p = 0.02), a lower incidence of adverse reactions (p = 0.002) and lower rate of mortality (p = 0.007). There was no difference in the rate of cough disappearance on Day 14 (p = 0.24) or the rate of severe/critical illness (p = 0.07) between the two groups. CONCLUSIONS: Arbidol may be superior to lopinavir/ritonavir in the treatment of COVID-19. However, due to the small number of included studies and the number of patients, high-quality multicenter large-sample randomized double-blind controlled trials are still needed for verification.

Sensing of C-Reactive Protein Using an Extended-Gate Field-Effect Transistor with a Tungsten Disulfide-Doped Peptide-Imprinted Conductive Polymer Coating.

C-reactive protein (CRP) is a non-specific biomarker of inflammation and may be associated with cardiovascular disease. In recent studies, systemic inflammatory responses have also been observed in cases of coronavirus disease 2019 (COVID-19). Molecularly imprinted polymers (MIPs) have been developed to replace natural antibodies with polymeric materials that have low cost and high stability and could thus be suitable for use in a home-care system. In this work, a MIP-based electrochemical sensing system for measuring CRP was developed. Such a system can be integrated with microfluidics and electronics for lab-on-a-chip technology. MIP composition was optimized using various imprinting template (CRP peptide) concentrations. Tungsten disulfide (WS2) was doped into the MIPs. Doping not only enhances the electrochemical response accompanying the recognition of the template molecules but also raises the top of the sensing range from 1.0 pg/mL to 1.0 ng/mL of the imprinted peptide. The calibration curve of the WS2-doped peptide-imprinted polymer-coated electrodes in the extended-gate field-effect transistor platform was obtained and used for the measurement of CRP concentration in real human serum.

Levocetirizine and montelukast in the COVID-19 treatment paradigm.

Levocetirizine, a third-generation antihistamine, and montelukast, a leukotriene receptor antagonist, exhibit remarkable synergistic anti-inflammatory activity across a spectrum of signaling proteins, cell adhesion molecules, and leukocytes. By targeting cellular protein activity, they are uniquely positioned to treat the symptoms of COVID-19. Clinical data to date with an associated six-month follow-up, suggests the combination therapy may prevent the progression of the disease from mild to moderate to severe, as well as prevent/treat many of the aspects of 'Long COVID,' thereby cost effectively reducing both morbidity and mortality. To investigate patient outcomes, 53 consecutive COVID-19 test (+) cases (ages 3-90) from a well-established, single-center practice in Boston, Massachusetts, between March - November 2020, were treated with levocetirizine and montelukast in addition to then existing protocols [2]. The data set was retrospectively reviewed. Thirty-four cases were considered mild (64%), 17 moderate (32%), and 2 (4%) severe. Several patients presented with significant comorbidities (obesity: n = 22, 41%; diabetes: n = 10, 19%; hypertension: n = 24, 45%). Among the cohort there were no exclusions, no intubations, and no deaths. The pilot study in Massachusetts encompassed the first COVID-19 wave which peaked on April 23, 2020 as well as the ascending portion of the second wave in the fall. During this period the average weekly COVID-19 case mortality rate (confirmed deaths/confirmed cases) varied considerably between 1 and 7.5% [37]. FDA has approved a multicenter, randomized, placebo-controlled, Phase 2 clinical trial design, replete with electronic diaries and laboratory metrics to explore scientific questions not addressed herein.

Capability of novel fluorescence DNA-conjugated CdTe/ZnS quantum dots nanoprobe for COVID-19 sensing.

Urgent identification of COVID-19 in infected patients is highly important nowadays. Förster or fluorescence resonance energy transfer (FRET) is a powerful and sensitive method for nanosensing applications, and quantum dots are essential materials in FRET-based nanosensors. The QDs are conjugated to DNA or RNA and used in many applications. Therefore, in the present study, novel fluorescence DNA-conjugated CdTe/ZnS quantum dots nanoprobe designed for detection of Covid-19 after extracting their RNA from saliva of hesitant people. For achieving this purpose, the water-soluble CdTe/ZnS QDs-DNA prepared via replacing the thioglycolic acid (TGA) on the surface of QDs with capture DNA (thiolated DNA) throw a ligand-exchange method. Subsequently, by adding the different concentrations of complementary (target DNA) in a mixture of quencher DNA (BHQ2-labeled DNA) and the QDs-DNA conjugates at different conditions, sandwiched hybrids were formed. The results showed that the fluorescence intensity was decreased with increasing the concentration of target DNA (as a positive control). The linear equation and regression (Y = 40.302 X  + 1 and R2 = 0.98) were obtained by using the Stern-Volmer relationship. The Limit of detection (LOD) was determined 0.000823 µM. The achieved results well confirm the outcomes of the RT-PCR method in real samples.

The neutralization effect of montelukast on SARS-CoV-2 is shown by multiscale in silico simulations and combined in vitro studies.

Small molecule inhibitors have previously been investigated in different studies as possible therapeutics in the treatment of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). In the current drug repurposing study, we identified the leukotriene (D4) receptor antagonist montelukast as a novel agent that simultaneously targets two important drug targets of SARS-CoV-2. We initially demonstrated the dual inhibition profile of montelukast through multiscale molecular modeling studies. Next, we characterized its effect on both targets by different in vitro experiments including the enzyme (main protease) inhibition-based assay, surface plasmon resonance (SPR) spectroscopy, pseudovirus neutralization on HEK293T/hACE2+TMPRSS2, and virus neutralization assay using xCELLigence MP real-time cell analyzer. Our integrated in silico and in vitro results confirmed the dual potential effect of montelukast both on the main protease enzyme inhibition and virus entry into the host cell (spike/ACE2). The virus neutralization assay results showed that SARS-CoV-2 virus activity was delayed with montelukast for 20 h on the infected cells. The rapid use of new small molecules in the pandemic is very important today. Montelukast, whose pharmacokinetic and pharmacodynamic properties are very well characterized and has been widely used in the treatment of asthma since 1998, should urgently be completed in clinical phase studies and, if its effect is proved in clinical phase studies, it should be used against coronavirus disease 2019 (COVID-19).

Phase III, Randomized, Double-blind, Placebo controlled trial of Efficacy, Safety and Tolerability of Antiviral drug Umifenovir vs Standard care of therapy in non-severe COVID-19 patients.

OBJECTIVE: To test efficacy, safety and tolerability of Umifenovir in non-severe COVID-19 adult patients. METHODS: We carried out randomized, double-blind, placebo-controlled, multicenter, phase III trials involving adult (18-75 years), non-severe COVID19 patients, randomized 1:1 on placebo or Umifenovir (800 mg BID, maximum 14 days) respectively along with standard-of-care. The primary endpoint for Asymptotic-mild patients was time to nasopharyngeal swab RT-PCR test negativity. For Moderate patients, the average change in the ordinal scale from the baseline scores on the eight-point WHO ordinal scale was assessed. RESULTS: 132 patients were recruited between 3rd October to 28th April 2021, of which 9 discontinued due to various reasons. In Mild-asymptomatic patients (n=82), we found that 73% patients in the Umifenovir arm were RT-PCR negative, while 40% patients in the placebo arm were negative (P=0.004) on day 5. However, in the moderate group (n=41), the WHO scores for the Umifenovir arm was not statistically significant (P=0.125 on day 3), while it was statistically significant in the Mild-asymptomatic group (P=0.019 on day 5). CONCLUSION: Umifenovir meets the primary and secondary endpoint criteria and exhibits statistically significant efficacy for Mild-asymptomatic patients. It is efficacious, safe and well-tolerated at the tested dosage of 800mg BID, maximum 14 days.

Potential Novel Thioether-Amide or Guanidine-Linker Class of SARS-CoV-2 Virus RNA-Dependent RNA Polymerase Inhibitors Identified by High-Throughput Virtual Screening Coupled to Free-Energy Calculations.

SARS-CoV-2, or severe acute respiratory syndrome coronavirus 2, represents a new pathogen from the family of Coronaviridae that caused a global pandemic of COVID-19 disease. In the absence of effective antiviral drugs, research of novel therapeutic targets such as SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) becomes essential. This viral protein is without a human counterpart and thus represents a unique prospective drug target. However, in vitro biological evaluation testing on RdRp remains difficult and is not widely available. Therefore, we prepared a database of commercial small-molecule compounds and performed an in silico high-throughput virtual screening on the active site of the SARS-CoV-2 RdRp using ensemble docking. We identified a novel thioether-amide or guanidine-linker class of potential RdRp inhibitors and calculated favorable binding free energies of representative hits by molecular dynamics simulations coupled with Linear Interaction Energy calculations. This innovative procedure maximized the respective phase-space sampling and yielded non-covalent inhibitors representing small optimizable molecules that are synthetically readily accessible, commercially available as well as suitable for further biological evaluation and mode of action studies.