Medicinal plants as rich sources of bioactive compounds are now being explored for drug development against COVID-19. 19 medicinal plants known to exhibit antiviral and anti-inflammatory effects were manually curated, procuring a library of 521 metabolites; this was virtually screened against NSP9, including some other viral and host targets and were evaluated for polypharmacological indications. Leads were identified via rigorous scoring thresholds and ADMET filtering. MM-GBSA calculation was deployed to select NSP9-Lead complexes and the complexes were evaluated for their stability and protein-ligand communication via MD simulation. We identified 5 phytochemical leads for NSP9, 23 for Furin, 18 for ORF3a, and 19 for IL-6. Ochnaflavone and Licoflavone B, obtained from Lonicera japonica (Japanese Honeysuckle) and Glycyrrhiza glabra (Licorice), respectively, were identified to have the highest potential polypharmacological properties for the aforementioned targets and may act on multiple pathways simultaneously to inhibit viral entry, replication, and disease progression. Additionally, MD simulation supports the robust stability of Ochnaflavone and Licoflavone B against NSP9 at the active sites via hydrophobic interactions, H-bonding, and H-bonding facilitated by water. This study promotes the initiation of further experimental analysis of natural product-based anti-COVID-19 therapeutics. Communicated by Ramaswamy H. Sarma

The phenolic structural analogues of synthetic antioxidants such as butylated hydroxytoluene (BHT) in essential oils have been reported to exhibit antioxidant properties. Additionally, their lipophilicity makes them suitable for use in lipid-rich foods. This study evaluated the antioxidant capacity of carvacrol, a monoterpenoid antioxidant compound in the Monodora myristica (Gaertn.) seed essential oil, compared to the seed essential oil and BHT. In vitro studies (ferric reducing antioxidant power (FRAP), metal chelating activity (MCA), and nitric oxide scavenging activity (NOSA)) were conducted to ascertain if the antioxidant capacity of carvacrol was comparable to that of the seed essential oil. The potential binding affinity and molecular interactions between carvacrol and lipoxygenase (LOX) and its homologous model were investigated in silico. The molecular docking was performed using Autodock Vina, and the best poses were subjected to molecular dynamics simulation. The IC₅₀ for MCA and NOSA were: carvacrol 50.29 µL/mL, seed essential oil (SEO) 71.06 µL/mL; and carvacrol 127.61 µL/mL, SEO 165.18 µL/mL, respectively. The LOX model was Ramachandran favoured (97.75%) and the overall quality factor in the ERRAT plot was 95.392. The results of the molecular docking and molecular dynamics simulations revealed that lipoxygenase has a higher affinity (−22.79 kcal/mol) for carvacrol compared to BHT. In the LOX–BHT and LOX–carvacrol complexes, the root-mean-square deviation (RMSD), root-mean-square fluctuation (RMSF), and the radius of gyration (RoG) were not significantly different, indicating similar molecular interactions. The results obtained from this study suggest that carvacrol exhibits an antioxidant capacity that may be explored as an alternative for crude essential oils and synthetic compounds during the storage of lipid-rich foods.

The continued use of potassium bromate in some food and cosmetic products in Nigeria against regulatory provision has continually exposed Nigerians to its deleterious effect. The mechanism of bromate induced damage in the liver and kidney is through oxidative stress. Phytochemicals have antioxidant capacity and have gained research interest in the management of oxidative stress. In this study, the effect of the ethanol extract of Aframomum angustifolium seed on kidney and liver damage induced by exposure to an acute dose of potassium bromate was measured using appropriate biomarkers. Eighteen male Wistar rats, randomly divided into 3 groups were used for the study. Group I (normal control) received distilled H2O; Group II (positive control) received 400 mg/kgbw bromate once while Group III (test) received same acute dose as Group II but thereafter treated with an oral dose of ethanol extract (750 mg/kgbw) for 10days. Half the populations of each group were sacrificed on day 3 while the remaining was sacrificed on day 10 of treatment. Liver and kidney tissues as well as blood samples were collected for analysis. Biochemical parameters; malondialdehyde, creatinine, electrolytes (Na+ and K+) concentration as well as catalase, alanine aminotransferase and alkaline phosphatase activities were measured using standard spectrophotometric procedures. In the kidney tissue, malondialdehyde concentration increased significantly in all groups from day 3 to day 10 but was highest in Group II. A similar trend was observed in the liver tissue but only group III increased significantly. Catalase activity was inhibited in Group II in both kidney and liver tissues and was significantly lower than test group. Serum Na+ decreased and K+ increased respectively but Group III were comparable to the Group I. Creatinine concentration increased in all groups but was highest in Group II though it was not significant. ALP activity was significantly higher (p0.05) on day 10. The results of this study suggests that ethanol extract of Aframomum angustifolium seeds can accelerate the in vivo repair of bromate induced hepato- and reno- toxicity in Wistar rats. Keywords: Aframomum angustifolium, bromate toxicity, malondialdehyde, antioxidant, phytochemicals.

Background: Medicinal plants, as rich sources of bioactive compounds with antiviral properties, are now being explored for the development of drugs against SARS-CoV-2.Aims: Identification of promising compounds for the treatment of COVID-19 from natural products via molecular modelling against NSP9, including some other viral and host targets and evaluation of polypharmacological indications.Main methods: A manually curated library of 521 phytochemicals (from 19 medicinal plants) was virtually screened using Mcule server and binding interactions were studied using DS Visualiser. Docking thresholds were set based on the scores of standard controls and rigorous ADMET properties were used to finally get the potential inhibitors. Free binding energies of the docked complexes were calculated employing MM-GBSA method. MM-GBSA informed our choice for MD simulation studies performed against NSP9 to study the stability of the drug-receptor interaction. NSP9 structure comparison was also performed. Key findings: Extensive screening of the molecules identified 5 leads for NSP9, 23 for Furin, 18 for ORF3a, and 19 for interleukin-6. Ochnaflavone and Licoflavone B, obtained from Lonicera japonica (Japanese Honeysuckle) and Glycyrrhiza glabra (Licorice), respectively, were identified to have the highest potential multi-target inhibition properties for NSP9, furin, ORF3a, and IL-6. Additionally, molecular dynamics simulation supports the robust stability of Ochnaflavone and Licoflavone B against NSP9 at the active sites via hydrophobic interactions, H-bonding, and H-bonding facilitated by water.Significance: These compounds with the highest drug-like ranking against multiple viral and host targets have the potential to be drug candidates for the treatment of SARS-CoV-2 infection that may possibly act on multiple pathways simultaneously to inhibit viral entry and replication as well as disease progression.