Repurposing of poly-gamma-glutamic acid, immunotherapeutic drug for cervical intraepithelial neoplasia 1, as covid-19 treatment

Covid-19 virus variants identified so far are due to viral genetic diversity, genetic evolution, and variable infectivity, suggesting that high infection rates and high mortality rates may be contributed by these mutations. And it has been reported that the targeting strategies for innate immunity should be less vulnerable to viral evolution, variant emergence and resistance. Therefore, the most effective solution to Covid-19 infection has been proposed to prevent and treat severe exacerbation of patients with moderate disease by enhancing human immune responses such as NK cell and T cell. In previous studies, we demonstrated for the first time that gamma-PGA induced significant antitumor activity and antiviral activity by modulating NK cell-mediated cytotoxicity. Especially intranasal administration of gamma-PGA was found to effectively induce protective innate and CTL immune responses against viruses and we found out that gamma-PGA can be an effective treatment for cervical intraepithelial neoplasia 1 through phase 2b clinical trial. In this study, the possibility of gamma-PGA as a Covid-19 immune modulating agent was confirmed by animal experiments infected with Covid-19 viruses. After oral administration of gamma-PGA 300mug/mouse once a day for 5 days in a K18-hACE2 TG mouse model infected with SARS-CoV-2 (NCCP 43326;original strain) and SARS-CoV-2 (NCCP 43390;Delta variant), virus titer and clinical symptom improvement were confirmed. In the RjHan:AURA Syrian hamster model infected with SARS-CoV-2 (NCCP 49930;Delta variant), 350 or 550 mug/head of gamma-PGA was administered orally for 10 days once a day. The virus for infection was administered at 5 x 104 TCID50, and the titer of virus and the improvement of pneumonia lesions were measured to confirm the effectiveness in terms of prevention or treatment. In the mouse model infected with original Covid-19 virus stain, the weight loss was significantly reduced and the survival rate was also improved by the administration of gamma-PGA. And gamma-PGA alleviated the pneumonic lesions and reduced the virus titer of lung tissue in mice infected with delta variant. In the deltavariant virus infected hamster model, gamma-PGA showed statistically significant improvement of weight loss and lung inflammation during administration after infection. This is a promising result for possibility of Covid-19 therapeutics along with the efficacy results of mouse model, suggesting gammaPGA can be therapeutic candidate to modulate an innate immune response for Covid-19.

Research progress of antiviral material basis and mechanism of Compound Qinlan Oral Liquid.

Compound Qinlan Oral Liquid (,CQOL) is derived from Yinqiao San (), which is composed of Jinyinhua (Lonicerae Japonicae Flos), Huangqin (Scutellariae Radix), Lianqiao (Forsythiae Fructus) and Banlangen (Isatidis Radix). It is a common clinical herbal medicine for clearing heat and detoxification, and has antiviral effects. By reviewing the active ingredients of CQOL and the research progress on its anti-influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) efficacy, with view to providing a basis for the clinical use of CQOL in treatment of respiratory diseases caused by SARS-CoV-2.Copyright © 2023 Editorial Office of Chinese Traditional and Herbal Drugs. All rights reserved.

Nanosponges: As a Dynamic Drug Delivery Approach for Targeted Delivery

Recent advancements in nanotechnology have resulted in improved medicine delivery to the target site. Nanosponges are three-dimensional drug delivery systems that are nanoscale in size and created by cross-linking polymers. The introduction of Nanosponges has been a significant step toward overcoming issues such as drug toxicity, low bioavailability, and predictable medication release. Using a new way of nanotechnology, nanosponges, which are porous with small sponges (below one microm) flowing throughout the body, have demonstrated excellent results in delivering drugs. As a result, they reach the target place, attach to the skin's surface, and slowly release the medicine. Nanosponges can be used to encapsulate a wide range of medicines, including both hydrophilic and lipophilic pharmaceuticals. The medication delivery method using nanosponges is one of the most promising fields in pharmacy. It can be used as a biocatalyst carrier for vaccines, antibodies, enzymes, and proteins to be released. The existing study enlightens on the preparation method, evaluation, and prospective application in a medication delivery system and also focuses on patents filed in the field of nanosponges.Copyright © 2023 The Authors.

Current status and hotspot of Lonicera Japonica Flos research based on bibliometrics.

In order to comprehensively understand the research hotspots and development trends of Lonicera Japonica Flos in the past 20 years, and to provide intuitive data reference and objective opinions and suggestions for subsequent related research in this field, this study collected 8 871 Chinese literature and 311 English literature related to Lonicera Japonica Flos research in the core collection databases of Wanfang Data), CNKI and Web of Science (WOS) from 2002 to 2021, and conducted bibliometric and visual analysis using vosviewer. The results showed that the research on the active components of Lonicera Japonica Flos based on phenolic acid components, the research on the mechanism of novel coronavirus pneumonia based on data mining and molecular docking technology, and the pharmacological research on the anti-inflammatory and antiviral properties of Lonicera Japonica Flos are the three hot research directions in the may become the future research direction. In this paper, we analyze the research on Lonicera Japonica Flos from five aspects: active ingredients, research methods, formulation and preparation, pharmacological effects and clinical applications, aiming to reveal the research hotspots, frontiers and development trends in this field and provide predictions and references for future research.Copyright © Drug Evaluation Research 2022.

ANTIVIRAL HERBS.

Objective: Viruses are agents that can infect all kinds of living organisms, and the most important hosts are humans, animals, plants, bacteria and fungi. Viral diseases are responsible for serious morbidity and mortality worldwide, are a major threat to public health, and remain a major problem worldwide. The recently prominent Coronaviruses (CoVs) within this group belong to the Coronaviridae family, subfamily Coronavirinae, and are large (genome size 26-32 kb), enveloped, single-stranded ribonucleic acid (RNA ) viruses that can infect both animals and humans. The world has experienced three epidemics caused by betaCoVs in the last two decades: SARS in 2002-03, MERS in 2012, and COVID-19, first identified in 2019. COVID-19 continues to be our current health problem and studies on the subject continue. Result and Discussion: The term "antiviral agents" is defined in very broad terms as substances other than virus-containing vaccine or specific antibody that can produce a protective or therapeutic effect for the clearly detectable effect of the infected host. Nature has the potential to cure humanity's helplessness against viruses with many different plant species with strong antiviral effects. During the screening of plants with antiviral effects, focusing on plants used in folk medicine is of great importance in terms of maximizing the benefit to humanity - saving time and effort by dealing with valuable ancient knowledge on a scientific basis. In this review, viral diseases and the plants used in these diseases and determined to be effective are mentioned.Copyright © 2022 University of Ankara. All rights reserved.

Antibacterial and Antiviral Activities of Microwave-assisted Thuja orientalis Extracts

In this study, the components of microwave-assisted extracts obtained from Thuja orientalis leaves were analyzed, and the cytotoxicity, antibacterial and antiviral activities were evaluated. The predominant components from microwave-assisted extraction were catechin, leucopelargonidin, arecatannin, quinolone, and kaempferol derivatives, which are classified in the fla-vonoid and tannin groups. We observed that the 0.11 mg/mL of extract concentration did not show cytotoxicity in HaCaT cells. The antibacterial activities were tested according to the guidelines of methods for determining the bactericidal activity of antimicrobial agents. The extracts showed 99.9% antibacterial efficiency against gram-positive S. aureus, while the anti-bacterial effect on gram-negative E. coli was insignificant. When the extract concentration and contact time with bacteria were increased, 99.9% antibacterial efficiency was observed for E. coli as well as S. aureus. Following the standard to assess the activity of microbicides against viruses in suspension (ASTM-E1052-20), the antiviral efficiency was more than 99.99% for influenza A (H1N1) and SARS-CoV-2. These results suggest its potential use in antiviral disinfectants, surface coatings, personal protective equipment, and textiles. © 2023 The Korean Society of Industrial and Engineering Chemistry. All rights reserved.

Improving the Dissolution Rate and the Bioavailability of Favipiravir by Solid Dispersion with Curcumin

Favipiravir is an anti-viral agent that inhibits RNA-dependent RNA polymerase of several RNA viruses and is approved for the treatment of influenza in Japan. It has a role as an antiviral drug, an anti-coronaviral (COVID-19) agent but the poor solubility of the favipiravir in the aqueous media of the human body cause a reduction in the effectiveness and bioavailability. In the current work, the favipiravir was formulated for the first time as solid dispersed system with curcumin to improve dissolution property and antiviral activity during treatment of Covid-19. Binary and ternary mix of favipiravir and curcumin with/without soluplus were prepared and characterized by Differential Scanning Calorimetry (DSC), Powder X-ray Diffractometry (PXRD) and Fourier Transform Infrared Spec-troscopy (FTIR) and subjected to the dissolution test by apparatus I according to the European Pharma-copeia. The antiviral activity was measured by its cytotoxicity against A549-hACE2 cells. The results re-vealed that there was a reduction in the crystallinity of both binary and ternary mixtures with an en-hancement of the dissolution in comparison with the pure drug which accompanied by an improvement in the antiviral activity which is promising results that need further .Copyright © 2023, Colegio de Farmaceuticos de la Provincia de Buenos Aires. All rights reserved.

Nanomedicine "New Food for an Old Mouth": Novel Approaches for the Treatment of COVID-19

Coronavirus disease (COVID-19) is an infectious disease caused by coronavirus. Devel-oping specific drugs for inhibiting replication and viral entry is crucial. Several clinical trial studies are underway to evaluate the efficacy of anti-viral drugs for COVID-19 patients. Nanomedicine formulations can present a novel strategy for targeting the virus life cycle. Nano-drug delivery systems can modify the pharmacodynamics and pharmacokinetics properties of anti-viral drugs and reduce their adverse effects. Moreover, nanocarriers can directly exhibit anti-viral effects. A number of nanocarriers have been studied for this purpose, including liposomes, dendrimers, exosomes and decoy nanoparticles (NPs). Among them, decoy NPs have been considered more as nanodecoys can efficiently protect host cells from the infection of SARS-CoV-2. The aim of this review article is to highlight the probable nanomedicine therapeutic strategies to develop anti-viral drug delivery systems for the treatment of COVID-19.Copyright © 2023 Bentham Science Publishers.

Trace Elements Zinc and Selenium: Their Significance in the Conditions of the Covid-19 Pandemic

Within the conditions of the ongoing COVID-19 pandemic, when many questions regarding prevention and treatment strategies remain unsolved and the search for the best antiviral agents is underway, attention should be paid to the role of trace elements zinc and selenium in increasing the body's resistance to viral infections and their direct antiviral activity against SARS-CoV-2. Experimental data show that trace elements zinc and selenium not only actthrough regulating the immune response at all levels of humoral and cellular immunity, but also can play a significant role in adjuvant therapy for viral diseases. This is especially relevant in the case of COVID-19. Studies of the direct antiviral effect of these micro-elements testify to its 3 main ways to SARS-Cov-2: I - counteraction to virus replication and its transcription through: (i) their covalent binding to the SH-group of the cysteine of the main protease M(Pro) of the virus;(ii) inhibition of its RNA polymerase activity by zinc;II - preventing the penetration of the virus into cells due to blocking SH-groups of protein disulfide isomerase (RDI) of the protein of its spikes (peplomers);III - decreasing the adsorption capacity of the virus due to the blocking of the electrostatic interaction of SARS-CoV-2 peplomers and angiotensin-converting enzyme (ACE-2) in ultra-low, uncharacteristic oxidation states (Zn+1and Se-2). The intensity of the antiviral action of these trace elements may depend on their chemical form. It was found that zinc citrate (a five-membered complex of zinc with citric acid) and monoselenium citric acid obtained with the help of nanotechnology have a greater intensity of action and higher chemical purity. Taking into account the immunostimulating and direct antiviral effect of zinc and selenium, their use in the form of pharmaceuticals and dietary supplements should be considered as adjunctive therapy for SARS-CoV-2 in patients, or as a preventive strategy for uninfected people from risk groups during the spread of COVID-19.Copyright © Publisher PH <<Akademperiodyka>> of the NAS of Ukraine, 2023.

Systematic computer analysis of the pharmacology of bioflavonoids in the context of increasing the body's antiviral defenses.

Background. The rapidly developing resistance of viruses to synthetic antiviral drugs indicates the need to use substances with multitarget action (to avoid polypharmacy and to improve the safety of treatment). Objective(s): systematic analysis of the scientific literature on the pharmacology of bioflavonoids with an emphasis on their antiviral action. Material and methods. More than 150,000 references of primary sources were found in the PubMed/MEDLINE database of biomedical publications, including 3282 references on the antiviral effects of bioflavonoids. A systematic computerized analysis of this array of publications was carried out in order to identify the main directions in the pharmacology of bioflavonoids with an emphasis on their antiviral, antibacterial and immunomodulatory effects. The literature analysis was carried out using modern methods of topological and metric analysis of big data. Results. The molecular mechanisms of action of baicalin, hesperidin, rutin, quercetin, leukodelphinidin bioflavonoids and epigallocatechin-3gallate, curcumin polyphenols, their anti-inflammatory, antioxidant, antiviral, bactericidal, angioprotective, regenerative effects, and their prospects in therapy, prevention and rehabilitation of patients with COVID-19 and other respiratory viral infections were described in detail. Conclusion. Bioflavonoids and synergistic polyphenols exhibit not only multitarget antiviral effects by inhibiting the main protease, spike proteins, and other target proteins, but also pronounced anti-inflammatory, hepatoprotective, and immunomodulatory effects.Copyright © 2023 Modern Medical Technology. All rights reserved.

Differential of antiviral activity between chloroquine and hydroxychloroquine sulfate against SARS-CoV-2 in vitro.

Objective To investigated the in vitro antiviral activity of chloroquine and hydroxychloroquine sulfate against different variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (Prototype, Beta, Delta, Omicron) by changing the sequence of drug and virus introduction. Methods Prophylactic treatment: Vero E6 cells were treated with Chloroquine or hydroxychloroquine sulfate (200.00, 150.00, 100.00, 50.00, 16.70, 5.55, 1.85, 0.62, 0.21 micromol.L-1) for 1 h, then the virus was added and incubated for another 2 h. The virus-drug mixture was repalced with fresh medium until the end of the experiment. Post-entry treatment: Vero E6 cells were incubated with virus for 2 h, then the virus was removed and the cells were cultured with drug-containing medium until the end of the experiment. Full-time treatment: Vero E6 cells were pretreated with the drug for 1 h ahead, then virus was added and incubated for another 2 h. The virus-drug mixture was discarded and the cells were cultured with drug-containing medium until the end of the experiment. After 72 h of culture, the cells were observed to see whether they became round and shed to determine the cytopathic situation, and the semi-maximum effect concentration (EC50) and drug selection index (SI) were calculated. Results Both drugs were less effective in preventing SARS-CoV-2. Chloroquine/hydroxychloroquine sulfate showed good antiviral activity under both therapeutic and full-time treatment. EC50 of hydroxychloroquine sulfate was less than chloroquine, SI was greater than chloroquine, antiviral effect of hydroxychloroquine sulfate was better than chloroquine. The antiviral effect of chloroquine (EC50 = 0.904 micromol.L-1) and hydroxychloroquine sulfate (EC50 = 0.143 micromol.L-1) was more significant against Omicron variant than other variants under therapeutic and full-time treatment conditions. Conclusion Chloroquine/hydroxychloroquine sulfate showed good antiviral activity under both therapeutic and full-time treatment, and both drugs were significantly more active against the Omicron variant than the other variants.Copyright © 2023 Authors. All rights reserved.

[Antiviral activity of basidial fungus Inonotus obliquus aqueous extract against SARS-CоV-2 virus (Coronaviridae: Betacoronavirus: Sarbecovirus) in vivo in BALB/c mice model].

INTRODUCTION: The COVID-19 pandemic combined with seasonal epidemics of respiratory viral diseases requires targeted antiviral prophylaxis with restorative and immunostimulant drugs. The compounds of natural origin are low-toxic, but active against several viruses at the same time. One of the most famous compounds is Inonotus obliquus aqueous extract. The fruit body of basidial fungus I. obliquus is called Chaga mushroom. The aim of the work ‒ was to study the antiviral activity of I. obliquus aqueous extract against the SARS-CoV-2 virus in vivo. MATERIALS AND METHODS: Antiviral activity of I. obliquus aqueous extract sample (#20-17) was analyzed against strain of SARS-CoV-2 Omicron ВА.5.2 virus. The experiments were carried out in BALB/c inbred mice. The SARS-CoV-2 viral load was measured using quantitative real-time PCR combined with reverse transcription. The severity of lung tissue damage was assessed by histological methods. RESULTS: The peak values of the viral load in murine lung tissues were determined 72 hours after intranasal inoculation at dose of 2,85 lg TCID50. The quantitative real-time PCR testing has shown a significant decrease in the viral load compared to the control group by 4,65 lg copies/ml and 5,72 lg copies/ml in the lung tissue and nasal cavity samples, respectively. Histological methods revealed that the decrease in the number and frequency of observed pathomorphological changes in murine lung tissues depended on the introduction of the compound under study. CONCLUSION: The results obtained indicate the possibility of using basidial fungus Inonotus obliquus aqueous extract as a preventive agent against circulating variants of SARS-CoV-2 virus.

Antiviral Activity of Pyrimidine Containing Compounds: Patent Review.

Viruses are still the most prevalent infectious pathogens on a worldwide scale, with many of them causing life-threatening illnesses in humans. Influenza viruses, because of their significant morbidity and mortality, continue to pose a major threat to human health. According to WHO statistics, seasonal influenza virus epidemics are predicted to cause over 2 million severe illness cases with high death rates yearly. The whole world has been suffering from the COVID-19 epidemic for two years and is still suffering so far, and the deaths from this virus have exceeded three million cases. Because the great majority of viral infections do not have a specific medication or vaccination, discovering novel medicines remains a vital task. This review covers reports in the patent literature from 1980 to the end of 2021 on the antiviral activities of pyrimidine moieties. The patent database, SciFinder, was used to locate patent applications. A large variety of pyrimidine molecules have been produced and tested for antiviral activity over the last decade. These molecules were reported to inhibit a wide range of viruses, including influenza virus, respiratory syncytial virus, rhinovirus, dengue virus, herpes virus, hepatitis B and C, and human immunodeficiency virus. The cytotoxicity of the developed pyrimidine derivatives was tested in almost all reported studies and the selectivity index was calculated to show the selectivity and safety of such molecules. From the remarkable activity of pyrimidine compounds as antivirals for several dangerous viruses, we expect that these derivatives will be used as potent drugs in the very near future.

[Antiviral and virucidal activity of sodium deoxyribonucleate and its complex with iron against viruses of different kingdoms and families].

INTRODUCTION: The urgent problem of modern medicine is the fight against acute respiratory viral infections (ARVI). To combat ARVI, drugs of wide antiviral potency are needed, as well as immunomodulating drugs. Such antiviral and immunomodulatory effects has sodium deoxyribonucleate (DNA-Na) and its complex with iron (DNA-Na-Fe) developed on the basis of double-stranded DNA of natural origin. AIM OF THE STUDY: To assess antiviral and virucidal activity of DNA-Na and DNA-Na-Fe against viruses of different kingdoms and families. MATERIALS AND METHODS: Antiviral and virucidal activity of DNA-Na and DNA-Na-Fe was assessed in cell cultures infected with viruses. RESULTS AND DISCUSSION: DNA-Na and DNA-Na-Fe had antiviral activity against adenovirus at concentrations of 2501000 mcg/ml. Antiviral effect of both drugs was not detected in case of poliovirus. DNA-Na and DNA-Na-Fe had antiviral activity against coronavirus in all administration schemes. EC50 for DNA-Na ~ 2500 mcg/ml, for DNA-Na-Fe ~ 1000 mcg/ml. In cells treated with DNA-Na-Fe, secretion of following proinflammatory cytokines was detected: Interleukin (IL) 1, IL-2, IL-6, IL-18, interferon- (IFN-), IFN-, as well as anti-inflammatory cytokines: IL-4, IL-10, antagonist of IL-1 receptor. Evidently, DNA-Na and DNA-Na-Fe have antiviral effect, but mechanism of action does not seem to be associated with specific effect on viral replication. Presence of virucidal activity of drugs against representatives of Coronaviridae, Adenoviridae, Picornaviridae, Retroviridae, Herpesviridae in vitro test in range of 1.03.0 lg TCID50 was identified. CONCLUSION: Presence of simultaneous antiviral and virucidal activity of DNA-Na and DNA-Na-Fe against adeno- and coronaviruses shows their prospects for prevention and treatment of ARVI.

The Interaction of the Transmembrane Domain of SARS-CoV-2 E-Protein with Glycyrrhizic Acid in Lipid Bilayer.

The interaction of the transmembrane domain of SARS-CoV-2 E-protein with glycyrrhizic acid in a model lipid bilayer (small isotropic bicelles) is demonstrated using various NMR techniques. Glycyrrhizic acid (GA) is the main active component of licorice root, and it shows antiviral activity against various enveloped viruses, including coronavirus. It is suggested that GA can influence the stage of fusion between the viral particle and the host cell by incorporating into the membrane. Using NMR spectroscopy, it was shown that the GA molecule penetrates into the lipid bilayer in a protonated state, but localizes on the bilayer surface in a deprotonated state. The transmembrane domain of SARS-CoV-2 E-protein facilitates deeper GA penetration into the hydrophobic region of bicelles at both acidic and neutral pH and promotes the self-association of GA at neutral pH. Phenylalanine residues of the E-protein interact with GA molecules inside the lipid bilayer at neutral pH. Furthermore, GA influences the mobility of the transmembrane domain of SARS-CoV-2 E-protein in the bilayer. These data provide deeper insight into the molecular mechanism of antiviral activity of glycyrrhizic acid.

Swine acute diarrhoea syndrome coronavirus (SADS-CoV) Nsp5 antagonizes type I interferon signaling by cleaving DCP1A.

Swine acute diarrhoea syndrome coronavirus (SADS-CoV), which is a recently discovered enteric coronavirus, is the major aetiological agent that causes severe clinical diarrhoea and intestinal pathological damage in pigs, and it has caused significant economic losses to the swine industry. Nonstructural protein 5, also called 3C-like protease, cleaves viral polypeptides and host immune-related molecules to facilitate viral replication and immune evasion. Here, we demonstrated that SADS-CoV nsp5 significantly inhibits the Sendai virus (SEV)-induced production of IFN-ß and inflammatory cytokines. SADS-CoV nsp5 targets and cleaves mRNA-decapping enzyme 1a (DCP1A) via its protease activity to inhibit the IRF3 and NF-κB signaling pathways in order to decrease IFN-ß and inflammatory cytokine production. We found that the histidine 41 and cystine 144 residues of SADS-CoV nsp5 are critical for its cleavage activity. Additionally, a form of DCP1A with a mutation in the glutamine 343 residue is resistant to nsp5-mediated cleavage and has a stronger ability to inhibit SADS-CoV infection than wild-type DCP1A. In conclusion, our findings reveal that SADS-CoV nsp5 is an important interferon antagonist and enhance the understanding of immune evasion by alpha coronaviruses.

Antibacterial and Antiviral Activities of Microwave-assisted Thuja orientalis Extracts

In this study, the components of microwave-assisted extracts obtained from Thuja orientalis leaves were analyzed, and the cytotoxicity, antibacterial and antiviral activities were evaluated. The predominant components from microwave-assisted extraction were catechin, leucopelargonidin, arecatannin, quinolone, and kaempferol derivatives, which are classified in the fla-vonoid and tannin groups. We observed that the 0.11 mg/mL of extract concentration did not show cytotoxicity in HaCaT cells. The antibacterial activities were tested according to the guidelines of methods for determining the bactericidal activity of antimicrobial agents. The extracts showed 99.9% antibacterial efficiency against gram-positive S. aureus, while the anti-bacterial effect on gram-negative E. coli was insignificant. When the extract concentration and contact time with bacteria were increased, 99.9% antibacterial efficiency was observed for E. coli as well as S. aureus. Following the standard to assess the activity of microbicides against viruses in suspension (ASTM-E1052-20), the antiviral efficiency was more than 99.99% for influenza A (H1N1) and SARS-CoV-2. These results suggest its potential use in antiviral disinfectants, surface coatings, personal protective equipment, and textiles. © 2023 The Korean Society of Industrial and Engineering Chemistry. All rights reserved.

Experimental and Clinical Evaluation of Mefloquine Effectiveness against the Infection Caused by Sars-Cov-2

The efficacy of mefloquine has not been studied in the in vivo experiments and clinical trials involving COVID-19 patients. The study was aimed to assess the effects of mefloquine on the SARS-CoV-2 accumulation in the lungs of infected animals and to study the efficacy and safety of mefloquine compared to hydroxychloroquine in patients with COVID-19. During the experiment, a total of 96 Syrian hamsters were infected with SARS-CoV-2. Accumulation of the virus in lungs was compared in the groups of animals treated with mefloquine and ribavirin and in the control group. During the clinical trial, the mefloquine and hydroxychloroquine safety and efficacy in patients with mild and moderate COVID-19 (172 individuals) was assessed based on the symptom changes over time and the computed tomography results. The experiment showed that the SARS-CoV-2 accumulation in the lungs of Syrian hamsters 6 days after infection and mefloquine treatment was 2.2 +/- 0.18 lg PFU/g, which was lower (p < 0.05) than in the control group (3.5 +/- 0.21 lg PFU/g) and ribavirin group (5.2 +/- 0.05 lg PFU/g). During the clinical trial, it was found that 50.0% of patients in the mefloquine group and 32.4% in the hydroxychloroquine group (p < 0.05) developed a mild disease, and the completely resolved respiratory failure was registered in 76.5% and 44.6%, respectively (p < 0.001). Adverse events were observed in 86.7 % and 77% of patients in the mefloquine and hydroxychloroquine groups, respectively (p > 0.05). Thus, during the experiment, mefloquine contributed to the faster virus titer reduction in the lungs. During the clinical trial, the mefloquine efficacy was non-inferiority or, based on a number of indicators, higher compared to hydroxychloroquine, with comparable safety.Copyright © Extreme Medicine.All right reserved.