In vitro evaluation of antiviral efficacy of a Siddha Formulation against SARS-CoV-2

Introduction: SARS-CoV-2 virus caused COVID-19 pandemic with 218 million cases and 45 million deaths world over. It has challenged the already overburdened healthcare systems and created an urgent need to investigate solutions present in other healthcare systems. In this study Kabasura Kudineer is investigated as an intervention to influence the immune response which is beneficial for the host and stop the viral replication. Methods: Kabasura Kudineer is a polyherbal formulation containing 15 herbal drugs mixed in equal quantity. It is an official Siddha formulation, used for phlegmatic fevers and flu-like symptoms. To conduct this study Vero E6 (CL1008), the African monkey kidney epithelial cell line was taken and infected with SARS-CoV-2 viral isolate. The Kabasura Kudineer was added in different concentrations; 0.5 mg/mL, 0.25 mg/mL, 0.12 mg/mL, 0.06 mg/mL and 0.03 mg/mL to the infected cells respectively. These cell plates were incubated for 3 days in 5% CO2 incubator. Remdesivir was used as a positive control. The cells were fixed with formaldehyde, stained with crystal violet and plaques were visualised. Plaques were counted as PFU/ml. Result: Kabasura Kudineer was found to exhibit good antiviral activity against SARS-CoV-2. The highest antiviral activity was 81.5% at a concentration of 0.5 mg/ml. The IC-50 value was found to be 0.2 mg/mL. Conclusion: The antiviral efficacy of Kabasura Kudineer in our study showed reduction in the viral load which supports the results of clinical studies. Kabasura Kudineer can be used widely in a clinical setting as a treatment for COVID-19.