Investigation of the inhibitory activity of extracts, fractions and secondary metabolites of Silene spp. (Caryophyllaceae) and Serratula cupuliformis (Asteraceae) on the replication of SARS-CoV-2 coronavirus

Aim. In vitro analysis of the inhibitory activity of extracts, fractions and secondary metabolites of plants of the genus Silene (Caryophylaceae) and Serratula cupuliformis (Asteraceae) on the replication of SARS-CoV-2.Material and Methods. Silene spp. and Serratula cupuliformis of the Siberian Botanical Garden of National Research Tomsk State University were used. Ethanol extracts and butanol fractions of Silene spp. were prepared. The flavonoid shaftoside and the ecdysteroid 20hydroxyecdysone from Lychnis chalcedonica were isolated. Analysis of BAS was carried out by the HPLC method. In vitro analysis of the inhibitory activity of extracts on SARS-CoV-2 replication was performed in Vero cell culture by direct inactivation (neutralization) of virions. Comparison samples were dry ethanol extracts of chaga (Inonotus obliquus, Basidiomycota), spices of cloves (Syzygium aromaticum, Myrtaceae) and root of licorice (Glycyrrhiza glabra L., Fabaceae).Results. The inhibitory activity of ethanol extracts and butanol fractions of Silene spp., as well as individual compounds (shaftozide and 20-E) was revealed in the range of 50% effective concentrations (EC50) when dissolved in water from 339.85 +/- 83.92 mu g/ml to 1.59 +/- 0.39 mu g/ml and when dissolved in DMSO from 119.34 +/- 26.34 mu g/ml to 2.22 +/- 0.57 mu g/ml, respectively. The butanol fraction of Serratula cupuliformis was active with EC50=21.74 +/- 4.80 and 27.42 +/- 6.05 mu g/mL. These results for some samples of Silene spp. and Serratula cupuliformis are comparable to the EC50 values of the comparators.Conclusion. The results obtained suggest the presence of biologically active substances in the herbal preparations studied that act destructively on virions of SARS-CoV-2 and affect one of the main stages of its "life" cycle - on the attachment to receptors of sensitive cells.

Investigation of the inhibitory activity of extracts, fractions and secondary metabolites of Silene spp. (Caryophyllaceae) and Serratula cupuliformis (Asteraceae) on the replication of SARS‐CoV‐2 coronavirus

Aim. In vitro analysis of the inhibitory activity of extracts, fractions and secondary metabolites of plants of the genus Silene (Caryophylaceae) and Serratula cupuliformis (Asteraceae) on the replication of SARS-CoV-2. Material and Methods. Silene spp. and Serratula cupuliformis of the Siberian Botanical Garden of National Research Tomsk State University were used. Ethanol extracts and butanol fractions of Silene spp. were prepared. The flavonoid shaftoside and the ecdysteroid 20-hydroxyecdysone from Lychnis chalcedonica were isolated. Analysis of BAS was carried out by the HPLC method. In vitro analysis of the inhibitory activity of extracts on SARS-CoV-2 replication was performed in Vero cell culture by direct inactivation (neutralization) of virions. Comparison samples were dry ethanol extracts of chaga (Inonotus obliquus, Basidiomycota), spices of cloves (Syzygium aromaticum, Myrtaceae) and root of licorice (Glycyrrhiza glabra L., Fabaceae). Results. The inhibitory activity of ethanol extracts and butanol fractions of Silene spp., as well as individual compounds (shaftozide and 20-E) was revealed in the range of 50% effective concentrations (EC50) when dissolved in water from 339.85±83.92 µg/ml to 1.59±0.39 µg/ml and when dissolved in DMSO from 119.34±26.34 µg/ml to 2.22±0.57 µg/ml, respectively. The butanol fraction of Serratula cupuliformis was active with EC50=21.74±4.80 and 27.42±6.05 µg/mL. These results for some samples of Silene spp. and Serratula cupuliformis are comparable to the EC50 values of the comparators. Conclusion. The results obtained suggest the presence of biologically active substances in the herbal preparations studied that act destructively on virions of SARS-CoV-2 and affect one of the main stages of its "life” cycle - on the attachment to receptors of sensitive cells. © 2023 The authors. South of Russia: ecology, development. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Inhibitory activity of dry ethanol extracts of Artemisia spp. on SARS-CoV-2 replication in vitro

Aim. In vitro analysis of the inhibitory activity of dry ethanol extracts of some Artemisia spp. growing in the Novosibirsk region for SARS-CoV-2 replication. Materials and Methods. The laboratory strain SARS-CoV-2/human/RUS/Nsk-FRCFTM-1/2020 was passed on Vero cell culture. Dry ethanol extracts of plant parts (stems, flowers, leaves) of six types of Artemisia were prepared. The types used were: A. vulgaris L.;A. glauca (Pall. Ex Willd.);A. dracunculus L. (from three growth locations);A. absinthium L.;A. frigida Willd.;and A. sieversiana Ehrh. ex Willd. Dry extracts were dissolved in DMSO. In vitro analysis of the inhibitory activity of extracts against SARS-CoV-2 (an infectious titer of 10(3) TCID50/ml) replication was performed in a Vero E6 cell culture. To do this, the method of direct inactivation (neutralization) of virions, as well as schemes of & ldquo;preventive & rdquo;and & ldquo;therapeutic & rdquo;of cells, were used. Comparison samples were dry ethanol extracts of Inonotus obliquus, Syzygium aromaticum L. and Camellia sinensis L. Results. Extracts of leaves of Artemisia spp. proved to be most effective in direct inactivation of virions. By equal and decreasing activity these are the species: A. vulgaris;A. dracunculus*;A. absinthium;A. dracunculus***;A. dracunculus**;A. frigid;A. glauca;and A. sieversiana with a 50% effective concentration of range 1.10 +/- 0.24 & ndash;11.72 +/- 2.89 mu g/ml. Extracts of flowers of A. vulgaris, A.glauca, A. dracunculus*, A. dracunculus**, A. dracunculus***, A. frigida and A. sieversiana also contain biologically active substances which act both destructively on virions and after the virus has entered cells. For extracts of stems consistently high values of EC50 were found for A. glauca (6.84 +/- 1.35;7.81 +/- 2.00 and 14.06 +/- 3.06 mu g/ml) according to the results of three experimental schemes. Conclusion. The results obtained can become the basis for the development of inexpensive domestic drugs for the treatment and/or prevention of COVID-19.

Inhibitory activity of tea compositions and their constituent ingredients on SARS-COV-2 replication in vitro

Aim. In vitro analysis of the inhibitory activity of aqueous extracts of ready-made tea compositions and their constituent ingredients on SARS-COV-2 replication. Material and Methods. The laboratory strain SARS-CoV-2/human/RUS/Nsk-FRCFTM-1/2020 was passivated on Vero cell culture. For the preparation of water extracts six types of experimental tea compositions (not containing flavorings) based on black and green tea or flowers of hibiscus as well as individual ingredients were used. Antiviral (inhibitory) activity of plant raw materials was studied in vitro according to the classical scheme of neutralization (inactivation) of the virus. Results. When compared with the main control sample of an aqueous extract of chaga (Inonotus obliquus) with a 50% effective concentration equal to 13.72±2.99 µg/ml against 103 TCPD50/ml of SARS-CoV-2, superior activity was found for extracts of the spice Syzygium aromaticum L. and black tea from Nepal. Approximately equal inhibitory activity was detected for extracts of tea compositions based on black tea with the addition of the grass Thymus altaicus and the spice S. aromaticum L. or with the addition of seeds of Carum carvi L. and the root of Angelica archangelica L. In addition, such activity was detected for extracts of tea compositions based on green tea from China with the addition of leaves of Mentha piperita L. and flowers of Lavandula angustifolia MILL. or with the addition of the peel of Citrus sinensis L. and seeds of Pimpinella anisum L. Extracts from individual plant raw materials used to make tea compositions were black teas from India, Argentina, Vietnam and Sri Lanka, leaves of M. piperita L. and flowers of L. angustifolia MILL. Cetraria islandica lichen, green tea and berries of Oxycoccus also showed antiviral activity. Conclusion. The results obtained suggest that tea compositions based on black and green tea with the addition of various plant raw materials in the form of a regular drink can be useful to people with COVID-19 infection. © 2022 The authors.

Cell and Organism Technologies for Assessment of the SARS-CoV-2 Infectivity in Fluid Environment.

Under conditions of COVID-19 pandemic, considerable amounts of SARS-CoV-2 contained in household, municipal, and medical wastewaters inevitably reach natural water bodies. Possible preservation of virus infectivity in liquid environment is of a paramount epidemiological importance. Experiments demonstrated that SARS-CoV-2 is resistant to multiple freezing/thawing cycles and retains its infectivity in tap and river water for up to 2 days at 20°C and 7 days at 4°C. In natural milk, its viability is preserved in a refrigerator for 6 days. The exposure of aquarium fish to the virus-containing water fails to cause any infection.

Development of a Purified Viral Preparation for Studies of COVID-19 (SARS-CoV-2) Biology.

Different methods for producing bulk quantities of concentrated and purified SARS-CoV-2 for the use as antigens and for the research into COVID-19 biology were tested.

Antigenic properties of sARs-CoV-2/human/RUs/nsk-FRCFtM-1/2020 coronavirus isolate from a patient in novosibirsk

Objective: isolation of coronavirus SARS-CoV-2 from clinical sample of patient with COVID-19 in Novosibirsk;obtaining a purified and inactivated viral antigen and study of its antigenic properties. Materials and methods: virus isolation was carried out in Vero cell culture from nasopharyngeal swab positive on SARS-CoV-2 RNA. The efficiency of SARS-CoV-2 replication in cell culture was assessed on the appearance of cytopathic effect (CPE) and the presence of viral RNA in cultural medium with reverse transcription – polymerase chain reaction (RT-PCR). Purification, concentration and inactivation of the viral preparation were carried out according to standard methods. The purity of the purified preparation and the profile of viral proteins were determined by electrophoresis in 10% polyacrylamide gel (PAG) with the addition of sodium dodecyl sulfate (SDS). The presence and specificity of viral proteins were detected using COVID-19 convalescent’s sera with enzyme-linked immunosorbent assay (ELISA) and immunoblotting. Results: SARS-CoV-2/human/ RUS/Nsk-FRCFTM-1/2020 isolate was obtained after passage on Vero cells from a virus-containing clinical sample. A purified, concentrated, inactivated, whole-virion antigen was obtained. It contains three structural proteins: glycoprotein S (approximately 200 kDa), nucleoprotein N (48 kDa), and matrix protein M (20-25 kDa). All viral proteins were detected with serum antibodies of COVID-19 convalescents. Conclusion: SARS-CoV-2 coronavirus can be isolated in Vero cell culture. The antigenic specificity of the three structural viral proteins (S, N, and M) is preserved in the purified inactivated viral preparation. The inactivated whole-virion antigen of SARS-CoV-2/human/RUS/Nsk-FRCFTM-1/2020 isolate can be used to study the antigenic immunomodulating properties of viral proteins, to obtain immune sera of laboratory animals, and also as a component of test systems for the detection of specific antibodies with ELISA and immunoblotting.