Background: Human coronavirus (SARS-CoV-2) is causing a pandemic with significant morbidity and mortality. As no effective novel drugs are available currently, drug repurposing is an alternative intervention strategy. Here we present an in silico drug repurposing study that implements successful concepts of computer-aided drug design (CADD) technology for repurposing known drugs to interfere with viral cellular entry via the spike glycoprotein (SARS-CoV-2-S), which mediates host cell entry via the hACE2 receptor. Methods: A total of 4015 known and approved small molecules were screened for interaction with SARS-CoV-2-S through docking studies and 15 lead molecules were shortlisted. Additionally, streptomycin, ciprofloxacin, and glycyrrhizic acid (GA) were selected based on their reported anti-viral activity, safety, availability and affordability. The 18 molecules were subjected to molecular dynamics (MD) simulation. Results: The MD simulation results indicate that GA of plant origin may be repurposed for SARS-CoV-2 intervention, pending further studies. Conclusions: Repurposing is a beneficial strategy for treating COVID-19 with existing drugs. It is aimed at using docking studies to screen molecules for clinical application and investigating their efficacy in inhibiting SARS-CoV-2-S. SARS-CoV-2-S is a key pathogenic protein that mediates pathogen-host interaction. Hence, the molecules screened for inhibitory properties against SARS-CoV-2-S can be clinically used to treat COVID-19 since the safety profile is already known.

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.

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Due to the huge demand for health care facilities, there is a need for safe therapeutic intervention which can reduce the need for extensive health care support. In that regard, the current study was aimed at performing Phase 1 clinical trial to determine the safety of plant formulation in 24 healthy volunteers and Phase 2 trials in 100 COVID-19 patients to determine the tolerability and impact on the level of COVID 19 specific inflammatory markers. The outcomes of the Phase 1study have suggested the safe usage of plant formulation in humans and encouraged to conduct Phase 2 clinical trial. In the Phase 2 trial, the plant formulation was evaluated in 100 COVID-19 patients along with the standard of care. In Phase 1 single dose of 500 mg plant formulation capsule was used as an intervention, while 1gm thrice a day of plant formulation for 14 days was the testing dose for Phase 2. During the Phase 1 trial, no adverse event was observed and all organ systems were normal in function. During the Phase 2 trial, 100 patients underwent randomization, 50 were assigned to receive plant formulation, and 50 to receive placebo. Three patients in the placebo and two patients in the plant formulation group had dropped out from the study. Hence, the primary analysis population included 95 patients (48 allocated to plant formulation and 47 to placebo). The COVID 19 specific inflammatory markers improved faster and became normal in the plant formulation treatment group. In conclusion, the plant formulation (ATRICOV 452) has been found to be safe in phases 1 and 2.

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.