Historical herbal texts from Switzerland : a potential source for plant- derived natural products against SARS-CoV-2

In search for more effective prophylactic and curative therapeutics against SARS-CoV-2, an ethnopharmcological approach was used to select 20 plants described in the “Arzneibuch von Hallwyl” (ABvH), an influential recipe text from 16th century Switzerland. Plants were selected based on specific historical uses possibly linked with the treatment of microbial or viral infections as well as inflammatory conditions. For each plant candidate, aqueous and hydroethanolic extracts have been produced, respectively. The prophylactic activity of extracts against SARS-CoV-2 was assessed using the CellTiter-Glo​ Luminescent Cell Viability Assay upon viral infection in vitro. Four plants showed promising activity; among them Sambucus nigra L. (leaves) and Artemisia vulgaris L. (aerial parts) showed an anti-SARS-CoV-2 potential both with an activity of≤33.3 µg/mL for their hydroethanolic extract. The findings confirm the historical traditional use in the area of infectious diseases. Accordingly, this study shows supportive evidence that an ethnopharmacological approach combined with robust in vitro methods effectively enables to screen for promising antiviral plant extracts against SARS-CoV-2.