Water Extract of the Chaga Medicinal Mushroom, Inonotus obliquus (Agaricomycetes), Inhibits SARS-CoV-2 Replication in Vero E6 and Vero Cell Culture Experiments.

The antiviral properties of water extracts from pharmaceutical raw materials of the chaga mushroom, Inonotus obliquus, were studied against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). All studies with infectious materials were carried out in an isolated virological laboratory of the State Research Center of Virology and Biotechnology Vector of Rospotrebnadzor, which has a sanitary and epidemiological conclusion for the right to work with pathogenic biological agents of I-II pathogenicity groups. Antiviral activity was determined by the ability of I. obliquus water extracts to inhibit the replication of SARS-CoV-2 (nCoV/Victoria /1/2020 strain) in Vero E6 and Vero cell cultures. The results of these studies showed that water extracts of I. obliquus are characterized by low toxicity in Vero and Vero E6 cell cultures and have antiviral activity against SARS-CoV-2. The 50% inhibitory concentration ranged from 0.75 to 11.6 µg/mL. A patent for the invention was received (Patent RU, 2741714 C 1, 2021).

Genome Features and In Vitro Activity against Influenza A and SARS-CoV-2 Viruses of Six Probiotic Strains.

PURPOSE: The aim of this work was to analyze the complete genome of probiotic bacteria Lactobacillus plantarum 8 RA 3, Lactobacillus fermentum 90 TC-4, Lactobacillus fermentum 39, Bifidobacterium bifidum 791, Bifidobacterium bifidum 1, and Bifidobacterium longum 379 and to test their activity against influenza A and SARS-CoV-2 viruses. METHODS: To confirm the taxonomic affiliation of the bacterial strains, MALDI TOF mass spectrometry and biochemical test systems were used. Whole genome sequencing was performed on the Illumina Inc. MiSeq platform. To determine the antiviral activity, A/Lipetsk/1V/2018 (H1N1 pdm09) (EPI_ISL_332798) and A/common gull/Saratov/1676/2018 (H5N6) (EPI_ISL_336925) influenza viruses and SARS-CoV-2 virus strain Australia/VIC01/2020 (GenBank: MT007544.1) were used. RESULTS: All studied probiotic bacteria are nonpathogenic for humans and do not contain the determinants of transmission-type antibiotic resistance and integrated plasmids. Resistance to antibiotics of different classes is explained by the presence of molecular efflux pumps of the MatE and MFS families. Cultures of L. fermentum 90 TC 4, L. plantarum 8 RA 3, and B. bifidum 791 showed a pronounced activity against influenza A viruses in MDCK cells. Activity against the SARS-CoV-2 virus was demonstrated only by the L. fermentum 90 TC 4 strain in VERO cells. CONCLUSIONS: The studied probiotic bacteria are safe, have antiviral activity, and are of great importance for the prevention of diseases caused by respiratory viruses that can also infect the human intestine.