Silymarin Inhibits In Vitro SARS-CoV-2 Infection In Vero E6 Cells

The study evaluated the in vitro ability of Silymarin to inhibit SARS-COV-2 infection on Vero Cells. We set out to evaluate the hypothesis that Silymarin has both preventive and curative against SARS-COV-2. To study this, we first evaluated the safety profile of Silymarin using the Drosophila melanogaster (Harwich strain) model. Silymarin tablet film coated 140 mg (Silybon-140) was used for the study. We evaluated the fly for acute toxicity, Locomotor performance, estimation of total thiol level, determination of Acetylcholinesterases (AchE) activity, Catalase activity, Glutathion-S-transferase(GST) activity and fecundity assay. To evaluate the in vitro activity of Silymarin against SARS-COV-2, SARS-COV-2 isolates from oropharyngeal swabs and confirmed using qRT-PCR were cultured in Vero E6 monolayer cells. Different concentrations of silymarin concentration were used to determine pre- or post-exposure activity. The result showed that daily exposure to silymarin dose between 50% to 2000% adult dose showed no adverse effect after 28 days. Treatment of Vero cells with silymarin at the concentration 250-500 ug/ml all revealed a pre-treatment effect to SARS-COV-2 in vitro and no inhibition effect was observed when the virus was first added before the addition of Silymarin. Silymarin had no adverse effect on D. melanogaster and can be used a preventive drug against SARS-COV-2. ### Competing Interest Statement The authors have declared no competing interest.