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Till now there is no approved treatment for COVID-19. Phenolic compounds are known to have antiviral activity against many viruses such as HCV and HIV, through their phenol rings interaction with viral proteins and/or RNA, or via its regulating MAP kinase signaling in host cell defense. The present study aimed to assess polyphenolic compounds (gallic acid, quercetin, caffeine, resveratrol, naringenin, benzoic acid, oleuropein and ellagic acid) as COVID-19 RNA-dependent RNA polymerase (PDB ID 6M71) inhibitors, using a molecular docking. Molecular docking of these polyphenols were performed using Autodock 4.0 and Chimera 1.8.1 programs. Drug likeness and polyphenols pharmacokinetic properties were calculated using SWISSADME prediction website (http://www.swissadme.ch/). Remdesivir and ribavirin were used as standard antiviral drugs for comparison. Docking analysis results, ranked by binding energy value (ΔG) of several tested ligands toward COVID-19 polymerase were; remdesivir > gallic acid > quercetin > caffeine > ribavirin > resveratrol > naringenin > benzoic acid > oleuropein > ellagic acid. The binding energies were -8.51, - 7.55, - 7.17, -6.10, - 6.01, - 5.79, - 5.69, - 5.54, - 4.94 and -4.59 kcal/mol, respectively. All tested polyphenols performed hydrogen bonds with one or two of the nucleotide triphosphate entry channel (NTP) amino acids in COVID-19 polymerase (ARG 555, ARG 555, LYS 545), except caffeine and oleuropein. Binding of polyphenols to NTP of COVID-19 polymerase may influence in the entry of the substrate and divalent cations into the central active site cavity, inhibiting the enzyme activity. It appears promising that, gallic acid and quercetin exhibited high binding affinity than ribavirin toward COVID-19 polymerase and expressed good drug likeness and pharmacokinetic properties. Therefore, gallic acid and quercetin may represent a potential treatment option for COVID-19. Further researches are urgently required to investigate the potential uses of these polyphenols in COVID-19 treatment. Additionally, resveratrol, naringenin, benzoic and ellagic acid seem to have the best potential to act as COVID-19 polymerase inhibitors.

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Till now there is no approved treatment for COVID-19. Phenolic compounds are known to have antiviral activity against many viruses such as HCV and HIV, through their phenol rings interaction with viral proteins and/or RNA, or via its regulating MAP kinase signaling in host cell defense. The present study aimed to assess polyphenolic compounds (gallic acid, quercetin, caffeine, resveratrol, naringenin, benzoic acid, oleuropein and ellagic acid) as COVID-19 RNA-dependent RNA polymerase (PDB ID 6M71) inhibitors, using a molecular docking. Molecular docking of these polyphenols were performed using Autodock 4.0 and Chimera 1.8.1 programs. Drug likeness and polyphenols pharmacokinetic properties were calculated using SWISSADME prediction website (http://www.swissadme.ch/). Remdesivir and ribavirin were used as standard antiviral drugs for comparison. Docking analysis results, ranked by binding energy value (ΔG) of several tested ligands toward COVID-19 polymerase were; remdesivir > gallic acid > quercetin > caffeine > ribavirin > resveratrol > naringenin > benzoic acid > oleuropein > ellagic acid.

Background Oxidative stress (OS) and inflammation are the central pathogenic events in liver diseases. In this study, the protective and therapeutic role of Carica Papaya Linn. seeds extract (SE) was evaluated against the hepatotoxicity induced by carbon tetrachloride (CCl4) in rats. Methods The air-dried papaya seeds were powdered and extracted with distilled water. The phytochemical ingredients, minerals, and antioxidant potentials were studied. For determination of the biological role of SE against hepatotoxicity induced by CCl4, five groups of adult male Sprague-Dawley rats were prepared (8 rats per each): C: control; SE: rats were administered with SE alone; CCl4: rats were injected subcutaneously with CCl4; SE-CCl4 group: rats were administered with SE orally for 2 weeks before and 8 weeks during CCl4 injection; SE-CCl4-SE group: Rats were administered with SE and CCl4 as mentioned in SE-CCl4 group with a prolonged administration with SE for 4 weeks after the stopping of CCl4 injection. Then, the markers of OS [lipid peroxidation (LP) and antioxidant parameters; glutathione (GSH), superoxide dismutase (SOD), glutathione-S-transferase (GST), glutathione peroxidase (GPx)], inflammation [nuclear factor (NF)-κB, tumor necrosis factor (TNF)-α, interleukin (IL)-6], fibrosis [transforming growth factor (TGF)-β], apoptosis [tumor suppressor gene (p53)], liver and kidney functions beside liver histopathology were determined. Results The phytochemical analyses revealed that SE contains different concentrations of phenolics, flavonoids, terpenoids, and minerals so it has potent antioxidant activities. Therefore, the treatment with SE pre, during, and/or after CCl4 administration attenuated the OS induced by CCl4 where the LP was reduced, but the antioxidants (GSH, SOD, GST, and GPx) were increased. Additionally, these treatments reduced the inflammation, fibrosis, and apoptosis induced by CCl4, since the levels of NF-κB, TNF-α, IL-6, TGF-β, and p53 were declined. Accordingly, liver and kidney functions were improved. These results were confirmed by the histopathological results. Conclusions SE has protective and treatment roles against hepatotoxicity caused by CCl4 administration through the reduction of OS, inflammation, fibrosis, and apoptosis induced by CCl4 and its metabolites in the liver tissues. Administration of SE for healthy rats for 12 weeks had no adverse effects. Thus, SE can be utilized in pharmacological tools as anti-hepatotoxicity.

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Among many tested enzymes, lipase was found to be the one most affected by schistosomiasis in human serum, where it is increased eightfold. Arylsulfatases A and B and aspartyl protease displayed a significant decrease in the serum, while other enzymes showed a significant increase. ␣-Amylase and Leucine aminopeptidase were significantly increased and arylsulfatase B showed a significant decrease. Arylsulfatase B from a patient's leucocytes did not show either changed kinetic behaviour or temperature-dependent conformational changes. These results indicate that the diminished activity of this enzyme may be attributed to an opposing mechanism of regulation.