Since the outbreak of the COVID-19 (coronavirus disease 19) pandemic, researchers have been trying to investigate several active compounds found in plants that have the potential to inhibit the proliferation of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2). The present study aimed to evaluate bioactive compounds found in plants using a molecular docking approach to inhibit the main protease (Mpro) and spike (S) glycoprotein of SARS-CoV-2. The evaluation was performed on the docking scores calculated using AutoDock Vina (AV) as a docking engine. A rule of five (Ro5) was calculated to determine whether a compound meets the criteria as an active drug orally in humans. The determination of the docking score was performed by selecting the best conformation of the protein-ligand complex that had the highest affinity (most negative Gibbs’ free energy of binding/ Δ G ). As a comparison, nelfinavir (an antiretroviral drug), chloroquine, and hydroxychloroquine sulfate (antimalarial drugs recommended by the FDA as emergency drugs) were used. The results showed that hesperidin, nabiximols, pectolinarin, epigallocatechin gallate, and rhoifolin had better poses than nelfinavir, chloroquine, and hydroxychloroquine sulfate as spike glycoprotein inhibitors. Hesperidin, rhoifolin, pectolinarin, and nabiximols had about the same pose as nelfinavir but were better than chloroquine and hydroxychloroquine sulfate as Mpro inhibitors. This finding implied that several natural compounds of plants evaluated in this study showed better binding free energy compared to nelfinavir, chloroquine, and hydroxychloroquine sulfate, which so far are recommended in the treatment of COVID-19. From quantum chemical DFT calculations, the ascending order of chemical reactivity of selected compounds was pectolinarin > hesperidin > rhoifolin > morin > epigallocatechin gallate. All isolated compounds’ C=O regions are preferable for an electrophilic attack, and O-H regions are suitable for a nucleophilic attack. Furthermore, Homo-Lumo and global descriptor values indicated a satisfactory remarkable profile for the selected compounds. As judged by the RO5 and previous study by others, the compounds kaempferol, herbacetin, eugenol, and 6-shogaol have good oral bioavailability, so they are also seen as promising candidates for the development of drugs to treat infections caused by SARS-CoV-2. The present study identified plant-based compounds that can be further investigated in vitro and in vivo as lead compounds against SARS-CoV-2.

The novel coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which initially appeared in Wuhan, China, in December 2019. Elderly individuals and those with comorbid conditions may be more vulnerable to this disease. Consequently, several research laboratories continue to focus on developing drugs to treat this infection because this disease has developed into a global pandemic with an extremely limited number of specific treatments available. Natural herbal remedies have long been used to treat illnesses in a variety of cultures. Modern medicine has achieved success due to the effectiveness of traditional medicines, which are derived from medicinal plants. The objective of this study was to determine whether components of natural origin from Iranian medicinal plants have an antiviral effect that can prevent humans from this coronavirus infection using the most reliable molecular docking method; in our case, we focused on the main protease (Mpro) and a receptor-binding domain (RBD). The results of molecular docking showed that among 169 molecules of natural origin from common Iranian medicinal plants, 20 molecules (chelidimerine, rutin, fumariline, catechin gallate, adlumidine, astragalin, somniferine, etc.) can be proposed as inhibitors against this coronavirus based on the binding free energy and type of interactions between these molecules and the studied proteins. Moreover, a molecular dynamics simulation study revealed that the chelidimerine–Mpro and somniferine–RBD complexes were stable for up to 50 ns below 0.5 nm. Our results provide valuable insights into this mechanism, which sheds light on future structure-based designs of high-potency inhibitors for SARS-CoV-2.

Since the outbreak of the COVID-19 (Coronavirus Disease 19) pandemic, researchers have been trying to investigate several active compounds found in plants that have the potential to inhibit the proliferation of SARS-CoV-2 (Severe acute respiratory syndrome coronavirus 2). The present study aimed to evaluate bioactive compounds found in plants by using a molecular docking approach to inhibit the Main Protease (Mpro) and Spike (S) glycoprotein of SARS-CoV-2. The evaluation was performed on the docking scores calculated using AutoDock Vina as a docking engine. A rule of five (RO5) was calculated to determine whether a compound meets the criteria as an active drug orally in humans. The determination of the docking score was done by selecting the best conformation of the protein-ligand complex that had the highest affinity (most negative Gibbs' free energy of binding / ΔG). As a comparison, nelfinavir (an antiretroviral drug), chloroquine and hydroxychloroquine sulfate (anti-malarial drugs recommended by the FDA as emergency drugs) were used. The results showed that hesperidin, nabiximols, pectolinarin, epigallocatechin gallate, and rhoifolin had better poses than nelfinavir, chloroquine, and hydroxychloroquine sulfate as spike glycoprotein inhibitors. Hesperidin, rhoifolin, pectolinarin, and nabiximols had about the same pose as nelfinavir, but were better than chloroquine and hydroxychloroquine sulfate as Mpro inhibitors. These plant compounds have the potential to be developed as specific therapeutic agents against COVID-19. Several natural compounds of plants evaluated in this study showed better binding free energy compared to nelfinavir, chloroquine, and hydroxychloroquine sulfate which so far are recommended in the treatment of COVID-19. As judged by the RO5 and previous study by others, the compounds kaempferol, herbacetin, eugenol, and 6-shogaol have good oral bioavailability, so they are also seen as promising candidates for the development lead compounds to treat infections caused by SARS-CoV-2.

Background: Since the outbreak of the coronavirus disease 2019 (COVID-19) pandemic, researchers have been trying to investigate several active compounds found in plants that have the potential to inhibit the proliferation of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), the cause of COVID-19. The search for plant-based antivirals against the SARS-CoV-2 is promising, as several plants have been shown to possess antiviral activities against betacoronaviruses (beta-CoVs) Objective: The present study aimed to evaluate bioactive compounds found in plants by using a molecular docking approach to inhibit Main Protease (Mpro) (PDB code: 6LU7) and Spike (S) Glycoprotein (PDB code: 6VXX) of SARS-CoV-2. Methods: Evaluation was performed on the docking scores calculated using AutoDock Vina as a docking engine. For each compound that was docked, a rule of five was calculated to determine whether a compound with certain pharmacological or biological activities might have chemical and physical properties that would make it an active drug orally in humans. Determination of the docking score was done by selecting the conformation of the ligand that has the lowest binding free energy (best pose). As a comparison, nelfinavir (an antiretroviral drug), chloroquine and hydroxychloroquine sulfate (anti-malarial drugs recommended by the FDA as emergency drugs) were used. Results: The results showed that hesperidine, cannabinoids, pectolinarin, epigallocatechin gallate, and rhoifolin had better poses than nelfinavir, chloroquine and hydroxychloroquine sulfate as spike glycoprotein inhibitors. Hesperidin, rhoifolin, pectolinarin, and cannabinoids had about the same pose as nelfinavir, but were better than chloroquine and hydroxychloroquine sulfate as Mpro/3CLpro inhibitors. These plant compounds have the potential to be developed as specific therapeutic agents against COVID-19. Conclusion: Several natural compounds of plants evaluated in this study showed better binding free energy compared to nelfinavir, chloroquine and hydroxychloroquine sulfate which so far are recommended in the treatment of COVID-19.

Background: Since the outbreak of the coronavirus disease 2019 (COVID-19) pandemic, researchers have been trying to investigate several active compounds found in plants that have the potential to inhibit the proliferation of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), the cause of COVID-19. The search for plant-based antivirals against the SARS-CoV-2 is promising, as several plants have been shown to possess antiviral activities against betacoronaviruses (beta-CoVs) Objective: The present study aimed to evaluate bioactive compounds found in plants by using a molecular docking approach to inhibit Main Protease (Mpro) (PDB code: 6LU7) and Spike (S) Glycoprotein (PDB code: 6VXX) of SARS-CoV-2. Methods: Evaluation was performed on the docking scores calculated using AutoDock Vina as a docking engine. For each compound that was docked, a rule of five was calculated to determine whether a compound with certain pharmacological or biological activities might have chemical and physical properties that would make it an active drug orally in humans. Determination of the docking score was done by selecting the conformation of the ligand that has the lowest binding free energy (best pose). As a comparison, nelfinavir (an antiretroviral drug), chloroquine and hydroxychloroquine sulfate (anti-malarial drugs recommended by the FDA as emergency drugs) were used. Results: The results showed that hesperidine, cannabinoids, pectolinarin, epigallocatechin gallate, and rhoifolin had better poses than nelfinavir, chloroquine and hydroxychloroquine sulfate as spike glycoprotein inhibitors. Hesperidin, rhoifolin, pectolinarin, and cannabinoids had about the same pose as nelfinavir, but were better than chloroquine and hydroxychloroquine sulfate as Mpro inhibitors. These plant compounds have the potential to be developed as specific therapeutic agents against COVID-19. Conclusion: Several natural compounds of plants evaluated in this study showed better binding free energy compared to nelfinavir, chloroquine and hydroxychloroquine sulfate which so far are recommended in the treatment of COVID-19.