Efficacy of selected Nigerian tropical plants in the treatment of COVID-19: in silico and in vitro investigations.

The whole world is still challenged with COVID-19 pandemic caused by Coronavirus-2 (SARS-CoV-2) which has affected millions of individuals around the globe. Although there are prophylactic vaccines being used, till now, there is ongoing research into discovery of drug candidates for total eradication of all types of coronaviruses. In this context, this study sought to investigate the inhibitory effects of six selected tropical plants against four pathogenic proteins of Coronavirus-2. The medicinal plants used in this study were selected based on their traditional applications in herbal medicine to treat COVID-19 and related symptoms. The biological activities (antioxidant, free radical scavenging, and anti-inflammatory activities) of the extracts of the plants were assessed using different standard procedures. The phytochemicals present in the extracts were identified using GCMS and further screened via in silico molecular docking. The data from this study demonstrated that the phytochemicals of the selected tropical medicinal plants displayed substantial binding affinity to the binding pockets of the four main pathogenic proteins of Coronavirus-2 indicating them as putative inhibitors of Coronavirus-2 and as potential anti-coronavirus drug candidates. The reaction between these phytocompounds and proteins of Coronavirus-2 could alter the pathophysiology of COVID-19, thus mitigating its pathogenic reactions/activities. In conclusion, phytocompounds of these plants exhibited promising binding efficiency with target proteins of SARS-COV-2. Nevertheless, in vitro and in vivo studies are important to potentiate these findings. Other drug techniques or models are vital to elucidate their compatibility and usage as adjuvants in vaccine development against the highly contagious COVID-19 infection.

Covid-19 treatment: Investigation on the phytochemical constituents of Vernonia amygdalina as potential Coronavirus-2 inhibitors.

The upsurge in the current cases of COVID-19 poses a major threat on human health and population all over the globe. The emergence of new infectious diseases and increase in frequency of drug resistant viruses demand effective and novel therapeutic agents. In this study, we used bioinformatics approach to investigate the possible inhibitory potentials of phytochemical constituents of Vernonia amygdalina towards coronavirus-2 major protease. Pharmacodynamics, pharmacokinetics and toxicological profiles of the compounds were also examined using the pkCSM server. All the phytochemicals showed good binding affinity to the binding pocket of PDB ID 6LU7. It was observed that veronicoside A exhibited the highest binding affinity when compared to remdesivir, hydroxy-vernolide, vernodalin, vernodalol, and vernolide. The amino acids LEU272, LEU287, GLY275, TYR237, LYS236, THR198, THR199, ARG131, and LYS5 were showed as the key residues for veronicoside A binding to human SARS-COV2 major protease. The Pharmacodynamics and pharmacokinetics results suggested that all the tested phytochemicals have significant drug likeness properties and they could be absorbed through the human intestine. Furthermore, all the tested phytochemicals are not hepatoxic and also exhibited non or relatively low toxic effects in human. Taken together, the results of this study indicated that all the tested phytochemicals are potential putative inhibitors of SARS-COV2 major protease with non or low toxicity effects. However, further experimental and clinical studies are needed to further explore their activities and validate their efficacies against COVID-19.