[Screening of antiviral activity of samples from chaga Inonotus obliquus and humic acid from brown coal on Vero cell culture against ectromelia virus (Poxviridae: Orthopoxvirus; ECTV)].

INTRODUCTION: The mouse-specific orthopoxvirus, ectromelia virus, is one of the best models that can be used to study key issues of pathogenesis, prevention, and treatment of smallpox, and to develop measures to increase virulence, transmissibility, or the ability to overcome vaccine immunity. The aim of the work is to screen the antiviral activity of samples from Inonotus obliquus chaga and humic acid from brown coal in vitro against ectromelia virus. MATERIALS AND METHODS: We used ectromelia virus, strain K-1 (reg. No V-142), obtained from the State Collection of Pathogens of Viral Infections and Rickettsioses of the State Scientific Center of Virology and Biotechnology "Vector"; Vero Е6 cell culture (No 70) from the Collection of cell cultures of the State Scientific Center of Virology and Biotechnology "Vector". Nine samples from chaga I. obliquus and humic acid from brown coal were used to evaluate the changes in the infectivity of the ectromelia virus on cell culture using 2 schemes of application of drugs and virus (preventive and therapeutic schemes), and to assess their cytotoxicity and antiviral activity. RESULTS: 50% cytotoxic concentration, 50% virus-inhibiting concentrations and selectivity index were determined for all samples. The studied samples were shown to be non-toxic to the monolayer of Vero cell culture in a dilution of 300 and more micrograms/ml, while demonstrated high antiviral activity against strain K-1 of ectromelia virus in two application schemes - preventive and curative. CONCLUSION: All samples tested for ectromelia virus in vitro can be considered promising for further development of drugs against diseases caused by orthopoxviruses.

[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 extracts of basidiomycetes and humic compounds substances against Human Immunodeficiency Virus (Retroviridae: Orthoretrovirinae: Lentivirus: Human immunodeficiency virus 1) and Herpes Simplex Virus (Herpesviridae: Simplexvirus: Human alphaherpesvirus 1)].

INTRODUCTION: One of the most urgent problem of modern medicine is the fight against the disease caused by the Human Immunodeficiency Virus (HIV) - HIV infection. The chemical compounds have improved the situation for infected people, but they are toxic, disrupt the metabolism and cannot eliminate the integrated virus from the body. The emergence of resistant HIV strains makes these treatments ineffective. Often, the death of HIV-infected people occurs as a result of the development of opportunistic infections caused by viruses of the Herpesviridae family. Therefore, the search for new therapeutic and preventive drugs that are less toxic and active against several viruses at the same time is relevant. Basidiomycetes, higher fungi, are a source of medicinal compounds that have antimicrobial properties, as well as antiviral ones. Humic compounds (HS) of various nature also have antiviral activity.The aim of the study was to obtain nontoxic compounds from the basidiomycete Inonotus obliquus and humic compounds from brown coals and to test their activity against viruses that are pathogenic to humans: HIV and Herpes Simplex Virus (HSV). MATERIAL AND METHODS: The antiviral activity of melanin extracts obtained from the culture of the chaga fungus Inonotus obliquus and HS from the brown coal of the Kansko-Achinsk Deposit was studied using a model of MT-4 lymphoblastoid cells infected with HIV type 1 (HIV-1) strains and a monolayer culture of Vero cells infected with HSV type 1 (HSV-1) using virological and statistical research methods. RESULTS AND DISCUSSION: It was found that all the studied compounds did not have a cytotoxic effect on cells at a concentration of 100 mcg/ml. It was shown that extracts of basidiomycetes and HS have antiviral activity against HIV-1 and HSV-1. EC 50 (50%-effective concentration) for HIV-1 was 3.7-5.0 mcg/ml, selectivity index 28-35. Antiherpetic activity was detected at a dose of 50-100 mcg/ml. The antiviral effectiveness of melanin compounds was established both in the «preventive¼ (2 hours before cell infection) and in the «therapeutic¼ regimen of drug administration, both for HIV-1 and HSV-1. The presence of antiviral activity of melanin and HS in relation to the RNA-containing HIV-1 virus and DNA-containing HSV-1 virus in our study coincides with the results of a number of authors in relation to influenza viruses, herpes virus, HIV, hepatitis B virus, Coxsackievirus, smallpox vaccine virus, which suggests that the type of nucleic acid in the virus does not play a fundamental role in the antiviral action of these drugs. It is also clear that HS is effective against both enveloped and non-enveloped viruses. CONCLUSION: In general, it can be concluded that melanin and humic compounds are characterized by low toxicity in the presence of both virucidal and antiviral activity. This allows us to consider the studied compounds as the basis for creating safe medicines that are effective against pathogens of various viral infections.

Toxicity and Antiviral Activity of the Extracts of Submerged Mycelium of Nematophagous Duddingtonia flagrans Fungus in Vero Cell Culture.

We studied toxicity and antiviral activity of aqueous and ethanol extracts of bioactive substances from the biomass of nematophagous fungus Duddingtonia flagrans prepared by submerged culturing of the mycelium. It is found that both extracts were characterized by low toxicity for cultured Vero cells and inhibited reproduction of DNA-viruses in this cell line. Ethanol extract of the fungus exhibited higher in vitro antiviral activity against Herpes simplex virus type 2, ectromelia virus, and vaccinia virus than water extract, which can be due to higher content of proteins, polysaccharides, flavonols, catechins, or carotenes or more effective their combination. The extracts of cultured mycelium of Duddingtonia flagrans fungus containing a complex of bioactive substances can be used for creation of broad-spectrum antiviral drugs against DNA-viruses.