Aim: Today, the COVID-19 pandemic, which causes deaths in 224 countries around the world, continues to show its effect all over the world. However, unfortunately, there are few studies that determine the effect of natural products derived from plants on COVID-19. However, as it is known, the source of most drugs is plants and medicinal aromatic plants have been used frequently for therapeutic purposes since the existence of humanity. The aim of this study is to investigate the cytotoxic effects of six medicinal plants such as Licorice (Glycyrrhiza glabra), Saffron (Crocus sativus L.), Black Cumin (Nigella sativa L.), Laurel (Lauris nobilis), Buckwheat (Lavandula stoechas) and Zahter (Thymbra spicata L. var. spicata) and their antiviral activities against SARS-CoV-2 in vitro conditions.
Material and Method: This study was carried out in two stages. In the first stage, plants were collected and extracts were obtained. At the beginning of the second stage, cytotoxic effects on vero cells at non-cytotoxic broad-spectrum concentrations against SARS-CoV-2 in cell culture of six medicinal plants were investigated. In this step, the concentration of six ethnobotanically important medicinal plants that were not cytotoxic to SARS-CoV-2 was determined. In the continuation of the second stage, the plants were evaluated for the determination of viral replication inhibition and their antiviral effectiveness against SARS-CoV-2. In this step, in vitro antiviral effects of plants against SARS-CoV-2 were determined at a concentration that did not show cytotoxic effects..
Results: The concentration of six plants used in the study without cytotoxic effects was determined.. Among the plants examined, it was determined that the only plant that was effective against SARS-CoV-2 in vitro conditions was the licorice plant (Glycyrrhiza glabra). The licorice plant was found to inhibit SARS-CoV-2 in vitro at the 2nd dilution (1:4) after the initial concentration.
Conclusion: According to the findings obtained from our study, it was determined that the licorice plant was effective against the SARS-CoV-2 in vitro conditions. Supported by further studies, it can be thought that our findings may contribute to the fight against the COVID-19 pandemic.
Keywords: SARS-CoV-2, Antiviral Efficacy, Plant Extract, Licorice (Glycyrrhiza glabra), Saffron (Crocus sativus L.), Black Cumin (Nigella sativa L.), Laurel (Lauris nobilis), Buckwheat (Lavandula stoechas), Zahter (Thymbra spicata L. var. spicata).