Orientin for COVID-19

Aim: Structure-based identification of natural compounds against SARS-CoV-2, Delta and Omicron target proteins. Materials & methods: Several known antiviral natural compounds were subjected to molecular docking and MD simulation against SARS-CoV-2 Mpro, Helicase and Spike, including Delta and Omicron Spikes. Results: Of the docked ligands, 20 selected for each complex exhibited overall good binding affinities (-7.79 to -5.06 kcal/mol) with acceptable physiochemistry following Lipinski's rule. Finally, two best ligands from each complex upon simulation showed structural stability and compactness. Conclusion: Quercetin-3-acetyl-glucoside, Rutin, Kaempferol, Catechin, Orientin, Obetrioside and Neridienone A were identified as potential inhibitors of SARS-CoV-2 Mpro, Helicase and Spike, while Orientin and Obetrioside also showed good binding-affinities with Omicron Spike. Catechin and Neridienone A formed stable complexes with Delta Spike.

Abstract Aims The aim of the present review was to highlight natural product investigations in silico and in vitro to find plants and chemicals that inhibit or stimulate angiotensin-converting enzyme 2 (ACE-2). Background The global reduction of incidents and fatalities attributable to infections with SARS-CoV-2 is one of the most public health problems. In the absence of specific therapy for coronavirus disease 2019 (COVID-19), phytocompounds generated from plant extracts may be a promising strategy worth further investigation, motivating researchers to evaluate the safety and anti-SARS-CoV-2 effectiveness of these ingredients. Objective To review phytochemicals in silico for anti-SARS-CoV-2 activity and to assess their safety and effectiveness in vitro and in vivo. Methods The present review was conducted using various scientific databases and studies on anti-SARS-CoV-2 phytochemicals were analyzed and summarized. The results obtained from the in silico screening were subjected to extraction, isolation, and purification. The in vitro studies on anti-SarcoV-2 were also included in this review. In addition, the results of this research were interpreted, analyzed, and documented on the basis of the bibliographic information obtained. Results This review discusses recent research on using natural remedies to cure or prevent COVID-19 infection. The literature analysis shows that the various herbal preparations (extracts) and purified compounds can block the replication or entrance of the virus directly to carry out their anti-SARS-CoV-2 effects. It is interesting to note that certain items can prevent SARS-CoV-2 from infecting human cells by blocking the ACE-2 receptor or the serine protease TMPRRS2. Moreover, natural substances have been demonstrated to block proteins involved in the SARS-CoV-2 life cycle, such as papain- or chymotrypsin-like proteases. Conclusion The natural products may have the potential for use singly or in combination as alternative drugs to treat/prevent COVID-19 infection, including blocking or stimulating ACE-2. In addition, their structures may provide indications for the development of anti-SARS-CoV-2 drugs.

Abstract Objectives The study aims to explore the potential of medicinal plants and their phytoconstituents as effective inhibitors of the coronavirus disease 2019 (COVID-19), caused by the SARS-CoV-2 virus. The focus is on investigating specific medicinal plants known for their pharmacological properties, such as: antioxidant, anti-inflammatory, and immunomodulatory effects, to determine their viability in developing COVID-19 treatments. Materials and methods This study involves a comprehensive study of medicinal plants, including: Withania somnifera (Ashwagandha) and Ocimum sanctum (Holy Basil), known for their beneficial health effects. Molecular docking studies were conducted to assess the interactions between phytoconstituents from these plants and SARS-CoV-2 proteins. The compounds’ drug-like characteristics and safety profiles were also evaluated to determine their potential as therapeutic agents. Results The molecular docking studies revealed that the phytoconstituents from the studied medicinal plants exhibit favourable interactions with SARS-CoV-2 proteins, suggesting their potential as therapeutic targets. These compounds demonstrated promising drug-like characteristics and safety profiles, indicating their suitability for further development as COVID-19-fighting medications. Discussion The results indicate that medicinal plants and their bioactive substances hold significant potential for developing therapies against COVID-19. The ability of these organic substances to interact with key viral proteins and provide various therapeutic benefits highlights their potential as multi-functional treatment options. However, further research is necessary to confirm these findings and to understand the full scope of their therapeutic efficacy and safety in clinical settings. Conclusions Medicinal plants and their phyto-constituents represent a promising avenue for developing effective treatments for COVID-19. The favourable interactions with SARS-CoV-2 proteins and the promising drug-like characteristics observed in this study suggest that these natural compounds could be integral in the fight against the COVID-19 pandemic. Further research and clinical trials are essential to fully validating their potential and translating these findings into practical medical applications.

AbstractTo attain promising pharmacotherapies, researchers have applied drug repurposing (DR) techniques to discover the candidate medicines to combat the coronavirus disease 2019 (COVID-19) outbreak. Although many DR approaches have been introduced for treating different diseases, only structure-based DR (SBDR) methods can be employed as the first therapeutic option against the COVID-19 pandemic because they rely on the rudimentary information about the diseases such as the sequence of the severe acute respiratory syndrome coronavirus 2 genome. Hence, to try out new treatments for the disease, the first attempts have been made based on the SBDR methods which seem to be among the proper choices for discovering the potential medications against the emerging and re-emerging infectious diseases. Given the importance of SBDR approaches, in the present review, well-known SBDR methods are summarized, and their merits are investigated. Then, the databases and software applications, utilized for repurposing the drugs against COVID-19, are introduced. Besides, the identified drugs are categorized based on their targets. Finally, a comparison is made between the SBDR approaches and other DR methods, and some possible future directions are proposed.

SARS-CoV-2, the causative agent of COVID-19, has led to over seven million deaths worldwide prior to May 2025. Despite widespread vaccination programs, COVID-19 remains a persistent global health challenge, underscoring the urgent need for new therapeutic approaches. Orientin is a flavonoid with reported antiviral activity, though its potential against SARS-CoV-2 remains poorly explored. This study aimed to investigate whether Orientin interacts with the viral Spike protein and impacts viral replication. Molecular docking simulations using DockThor were employed to predict the binding affinity between Orientin and the receptor-binding domain (RBD) of the Spike protein. Fluorescence spectroscopy assays were performed to assess direct interactions between Orientin and the trimeric form of the Spike protein. Additionally, cytotoxicity and viral replication assays were carried out in Vero cells to evaluate Orientin’s antiviral effects. Docking results indicated that Orientin likely binds to key RBD residues involved in ACE2 receptor recognition. Spectroscopic analyses showed a decrease in intrinsic tryptophan fluorescence, suggesting direct interaction. Orientin demonstrated no cytotoxicity in Vero cells and exhibited moderate inhibition of viral replication. These findings suggest that Orientin interacts with critical regions of the Spike protein and may act as a moderate in vitro inhibitor of SARS-CoV-2, warranting further investigation into its therapeutic potential.

The ongoing COVID-19 pandemic has resulted in a global panic because of its continual evolution and recurring spikes. This serious malignancy is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since the outbreak, millions of people have been affected from December 2019 till now, which has led to a great surge in finding treatments. Despite trying to handle the pandemic with the repurposing of some drugs, such as chloroquine, hydroxychloroquine, remdesivir, lopinavir, ivermectin, etc., against COVID-19, the SARS-CoV-2 virus continues its out-of-control spread. There is a dire need to identify a new regimen of natural products to combat the deadly viral disease. This article deals with the literature reports to date of natural products showing inhibitory activity towards SARS-CoV-2 through different approaches, such as in vivo, in vitro, and in silico studies. Natural compounds targeting the proteins of SARS-CoV-2—the main protease (Mpro), papain-like protease (PLpro), spike proteins, RNA-dependent RNA polymerase (RdRp), endoribonuclease, exoribonuclease, helicase, nucleocapsid, methyltransferase, adeno diphosphate (ADP) phosphatase, other nonstructural proteins, and envelope proteins—were extracted mainly from plants, and some were isolated from bacteria, algae, fungi, and a few marine organisms.

AbstractThis study deals with the comprehensive phytochemical composition and antiviral activity against SARS‐CoV‐2 of acidic (non‐decarboxylated) and neutral (decarboxylated) ethanolic extracts from seven high‐cannabidiol (CBD) and two high‐Δ9‐tetrahydrocannabinol (Δ9‐THC) Cannabis sativa L. genotypes. Their secondary metabolite profiles, phytocannabinoid, terpenoid, and phenolic, were determined by LC‐UV, GC‐MS, and LC‐MS/MS analyses, respectively. All three secondary metabolite profiles, cannabinoid, terpenoid, and phenolic, varied significantly among cannabinoid extracts of different genotypes. The dose–response analyses of their antiviral activity against SARS‐CoV‐2 showed that only the single predominant phytocannabinoids (CBD or THC) of the neutral extracts exhibited antiviral activity (all IC50 < 10.0 μM). The correlation matrix between phytoconstituent levels and antiviral activity revealed that the phenolic acids, salicylic acid and its glucoside, chlorogenic acid, and ferulic acid, and two flavonoids, abietin, and luteolin, in different cannabinoid extracts from high‐CBD genotypes are implicated in the genotype‐distinct antagonistic effects on the predominant phytocannabinoid. On the other hand, these analyses also suggested that the other phytocannabinoids and the flavonoid orientin can enrich the extract's pharmacological profiles. Thus, further preclinical studies on cannabinoid extract formulations with adjusted non‐phytocannabinoid compositions are warranted to develop supplementary antiviral treatments.