Background In the absence of a specific drug for COVID 19, treatment with plant extracts could be an option worthy of further investigation and has motivated to evaluate the safety and anti-SARS-CoV-2 activity of plant extracts. Purpose To screen the phytochemicals for anti-SARS-CoV-2 in silico and evaluate their safety and efficacy in vitro and in vivo. Method The phytochemicals for anti-SARS-CoV-2 were screened in silico using molecular docking. The hits generated from in silico screening were subjected for extraction, isolation and purification. The anti-SARS-CoV-2 activity of Zanthoxylum piperitum (E1), Withania somnifera (E2), Calophyllum inophyllum (E3), Andrographis paniculata (E4), Centella asiatica (E5) ethanol extracts. The aerial parts were used for E1, E3, E4, E5 and root was used for E2. The in vitro safety and anti-SARS-CoV-2 activity of plant methanol extracts were performed in VeroE6 cells using Remdesivir as positive control. The acute and sub-acute toxicity study was performed in Wistar male and female rats. Results The percentage of cell viability for E4, E5 and E2 treated VeroE6 cells were remarkably good on the 24th and 48th hour of treatment. The in vitro anti-SARS-CoV-2 activity of E4, E5 and E2 were significant for both E gene and N gene. The percentage of SARS-CoV-2 inhibition for E4 was better than Remdesivir. For E gene and N gene, Remdesivir showed IC 50 of 0.15 µM and 0.11 µM respectively, For E gene and N gene, E4 showed IC 50 of 1.18 µg and 1.16 µg respectively. Taking the clue from in vitro findings, the E4 , E5 and E2 were combined (E 4.5.2) and evaluated for acute and sub-acute toxicity in Wistar male and female rats. No statistically significant difference in haematological, biochemical and histopathological parameters were noticed. Conclusion The study demonstrated the anti-SARS-CoV-2 activity in vitro and safety of plant extracts in both in vitro and in vivo experimental conditions.

Human coronavirus (SARS-CoV-2) is causing a pandemic with significant morbidity and mortality. Although, no effective novel drugs are available, drug repurposing is emerging as an effective strategy. In this study, we present an in silico drug repurposing study implementing successful concepts of computer aided drug design (CADD) technology with an objective to repurpose known drugs to interfere the viral cellular entry via the spike glycoprotein (SARS-CoV-2-S), which mediates the virus–cell receptor interaction. SARS-CoV-2-S uses ACE2 to enter cells. Totally, 4015 known and approved small molecules were screened for interaction with SARS-CoV-2 S through docking studies and 15 lead molecules were shortlisted. Further, three molecules streptomycin, ciprofloxacin and Glycyrrhizic acid (GA) were selected based on their reported anti-viral activity, safety, availability, affordability and subjected for Molecular Dynamics (MD) simulation. The MD simulation results indicate that GA from plant origin may be repurposed against SARS-CoV-2 and further studies are needed for validation.

Background: In the absence of a specific drug for COVID 19, treatment with plant extracts could be an option worthy of further investigation. Purpose: To screen the phytochemicals for Anti-SARS-CoV-2 in silico and evaluate their safety and efficacy in vitro and in vivo. Method: The phytochemicals for Anti-SARS-CoV-2 were screened in silico using molecular docking. The hits generated from in silico screening were subjected for extraction, isolation and purification. The anti-SARS-CoV-2 activity of plant extracts of Z. piperitum (ATRI-CoV-E1), W. somnifera (ATRI-CoV-E2), C. inophyllum (ATRI-CoV-E3), A. paniculata (ATRI-CoV-E4), and C. Asiatica (ATRI-CoV-E5). The in vitro safety and anti-SARS-CoV-2 activity of plant extracts were performed in VeroE6 cells using Remdesivir as positive control. The acute and sub-acute toxicity study was performed in Wistar male and female rats. Results: The percentage of cell viability for ATRI-COV-E4, ATRI-COV-E5 and ATRI-COV-E2 treated VeroE6 cells were remarkably good on the 24th and 48th hour of treatment. The in vitro anti-SARS-CoV-2 activity of ATRI-COV-E4, ATRI-COV-E5 and ATRI-COV-E2 were significant for both E gene and N gene. The percentage of SARS-CoV-2 inhibition for ATRI-COV-E4 was better than Remdesivir. For E gene and N gene, Remdesivir showed IC50 of 0.15 micromolar and 0.11 micromolar respectively, For E gene and N gene, ATRI-CoV-E4 showed IC50 of 1.18 microgram and 1.16 microgram respectively. Taking the clue from in vitro findings, the plant extracts A. paniculata (ATRI-COV-E4), W. somnifera extract (ATRI-COV-E5) and C. asiatica extract (ATRI-COV-E2) were combined (ATRICOV 452) and evaluated for acute and sub-acute toxicity in Wistar male and female rats. No statistically significant difference in haematological, biochemical and histopathological parameters were noticed. Conclusion: The study demonstrated the Anti-SARS-CoV-2 activity in vitro and safety of plant extracts in both in vitro and in vivo experimental conditions.