Antiviral natural products and herbal medicines

Discovery of Natural Bisbenzylisoquinoline Analogs from the Library of Thai Traditional Plants as SARS-CoV-2 3CLPro Inhibitors: In Silico Molecular Docking, Molecular Dynamics, and In Vitro Enzymatic Activity

The emergence of SARS-CoV-2 in December 2019 has become a global issue due to the continuous upsurge in patients and the lack of drug efficacy for treatment. SARS-CoV-2 3CL^Pro is one of the most intriguing biomolecular targets among scientists worldwide for developing antiviral drugs due to its relevance in viral replication and transcription. Herein, we utilized computer-assisted drug screening to investigate 326 natural products from Thai traditional plants using structure-based virtual screening against SARS-CoV-2 3CL^Pro. Following the virtual screening, the top 15 compounds based on binding energy and their interactions with key amino acid Cys145 were obtained. Subsequently, they were further evaluated for protein-ligand complex stability via molecular dynamics simulation and binding free energy calculation using molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) approaches. Following drug-likeness and ADME/Tox assessments, seven bisbenzylisoquinolines were obtained, including neferine (3), liensinine (4), isoliensinine (5), dinklacorine (8), tiliacorinine (13), 2'-nortiliacorinine (14), and yanangcorinine (15). These compounds computationally showed a higher binding affinity than native N3 and GC-373 inhibitors and attained stable interactions on the active site of 3CL^pro during 100 ns in molecular dynamics (MD) simulation. Moreover, the in vitro enzymatic assay showed that most bisbenzylisoquinolines could experimentally inhibit SARS-CoV-2 3CL^Pro. To our delight, isoliensinine (5) isolated from Nelumbo nucifera demonstrated the highest inhibition of protease activity with the IC₅₀ value of 29.93 μM with low toxicity on Vero cells. Our findings suggested that bisbenzylisoquinoline scaffolds could be potentially used as an in vivo model for the development of effective anti-SARS-CoV-2 drugs.

Chetomin, a SARS-CoV-2 3C-like Protease (3CLpro) Inhibitor: In Silico Screening, Enzyme Docking, Molecular Dynamics and Pharmacokinetics Analysis

The emergence of the Coronavirus Disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has led to over 6 million deaths. The 3C-like protease (3CLpro) enzyme of the SARS-CoV-2 virus is an attractive druggable target for exploring therapeutic drug candidates to combat COVID-19 due to its key function in viral replication. Marine natural products (MNPs) have attracted considerable attention as alternative sources of antiviral drug candidates. In looking for potential 3CLpro inhibitors, the MNP database (>14,000 molecules) was virtually screened against 3CLpro with the assistance of molecular docking computations. The performance of AutoDock and OEDocking software in anticipating the ligand-3CLpro binding mode was first validated according to the available experimental data. Based on the docking scores, the most potent MNPs were further subjected to molecular dynamics (MD) simulations, and the binding affinities of those molecules were computed using the MM-GBSA approach. According to MM-GBSA//200 ns MD simulations, chetomin (UMHMNP1403367) exhibited a higher binding affinity against 3CLpro than XF7, with ΔGbinding values of −55.5 and −43.7 kcal/mol, respectively. The steadiness and tightness of chetomin with 3CLpro were evaluated, revealing the high stabilization of chetomin (UMHMNP1403367) inside the binding pocket of 3CLpro throughout 200 ns MD simulations. The physicochemical and pharmacokinetic features of chetomin were also predicted, and the oral bioavailability of chetomin was demonstrated. Furthermore, the potentiality of chetomin analogues −namely, chetomin A-D− as 3CLpro inhibitors was investigated. These results warrant further in vivo and in vitro assays of chetomin (UMHMNP1403367) as a promising anti-COVID-19 drug candidate.

Traditional Herbal Remedies in the Management of Metabolic Disorders in Ethiopia: A Systematic Review of Ethnobotanical Studies and Pharmacological Activities

Background

MetS are common throughout the world, including Ethiopia. These have traditionally been treated using medicinal plants, particularly in rural areas where they are freely accessible. This systematic review tried to investigate the treatment of MetS with Ethiopian medicinal herbs and made recommendations for more validation research. A careful analysis of the literature was also conducted on the therapeutic effects of these and other Ethiopian medicinal plants with hepatoprotective and antihypertensive activities.

Methods

The relevant keywords "Ethnomedicinal + hypertension," "Ethnopharmacological + hypertension," "Ethnomedicinal + hepatitis, jaundices, and liver disease," "Ethnopharmacological + hepatic disorder," and "Ethnomedicinal + weight loss" were used to search for relevant articles in the major electronic scientific databases, including PubMed, Science Direct, Web of Science, and Google Scholar. The search strategy included all articles with descriptions that were accessible until April 30, 2022. The study's subjects, methods, or year of publication were no restrictions in the search. The outcomes were compiled using descriptive statistics.

Results

Fifty-four (54) studies were examined in the review that satisfied the inclusion and exclusion criteria for the treatment of MetS in Ethiopia. The most often used ethnobotanical plant species for the treatment of hypertension and hepatic disorders were Moringa stenopetala and Croton macrostachyus. Both hepatic and hypertensive disorders were treated more frequently with leaves (52% and 39%, respectively) than with roots (20% and 13%, respectively). Some intriguing studies came from an ethnobotanical investigation into medicinal herbs' hepatoprotective and antihypertensive properties. The most often investigated medicinal plant for its antihypertensive effects is Moringa stenopetala.

Conclusion

The study revealed that Ethiopians often use anti-MetS herbal remedies. We advocate the experimental validation of the commonly used medicinal plants with the identification of active compounds and the development of effective alternative drugs for the treatment of MetS.

Inhibitory effect of phytochemicals towards SARS-CoV-2 papain like protease (PLpro) proteolytic and deubiquitinase activity

Recent studies have shown that RNA-dependent RNA polymerase (RdRp), 3-chymotrypsin-like protease (3CLpro), and papain-like protease (PLpro) are necessary for SARS-CoV-2 replication. Among these three enzymes, PLpro exhibits both proteolytic and deubiquitinase (DUB) activity and is responsible for disrupting the host's innate immune response against SARS-CoV-2. Because of this unique property of PLpro, we investigated the inhibitory effects of phytochemicals on the SARS-CoV-2 PLpro enzyme. Our data indicates that the phytochemicals such as catechin, epigallocatechin gallate (EGCG), mangiferin, myricetin, rutin, and theaflavin exhibited inhibitory activity with IC₅₀ values of 14.2, 128.4, 95.3, 12.1, and 43.4, and 7.3 μM, respectively, towards PLpro proteolytic activity. However, the IC₅₀ values of quercetin, oleuropein, and γ-mangostin are ambiguous. We observed that EGCG, mangiferin, myricetin, oleuropein, rutin, and theaflavin have also inhibited the DUB activity with IC₅₀ values of 44.7, 104.3, 29.2, 131.5, 61.7, and 13.2 μM, respectively. Mechanistically, the ligand-protein interaction structural modeling suggests that mangiferin, EGCG, theaflavin, and oleuropein shows that these four ligands interact with Glu¹⁶⁷, and Tyr²⁶⁸, however mangiferin and oleuropein showed very weak interaction with Glu¹⁶⁷ as compared to EGCG, and theaflavin which reflects their low IC₅₀ values for DUB activity. Our data indicate that the phytochemicals mentioned above inhibit the proteolytic and DUB activity of SARS-CoV-2 PLpro, thus preventing viral replication and promoting host innate immune response. However, the therapeutic potential of these phytochemicals needs to be validated by pre-clinical and clinical studies.

A knowledge-based protein-protein interaction inhibition (KPI) pipeline: an insight from drug repositioning for COVID-19 inhibition

The inhibition of protein-protein interactions (PPIs) by small molecules is an exciting drug discovery strategy. Here, we aimed to develop a pipeline to identify candidate small molecules to inhibit PPIs. Therefore, KPI, a Knowledge-based Protein-Protein Interaction Inhibition pipeline, was introduced to improve the discovery of PPI inhibitors. Then, phytochemicals from a collection of known Middle Eastern antiviral herbs were screened to identify potential inhibitors of key PPIs involved in COVID-19. Here, the following investigations were sequenced: 1) Finding the binding partner and the interface of the proteins in PPIs, 2) Performing the blind ligand-protein inhibition (LPI) simulations, 3) Performing the local LPI simulations, 4) Simulating the interactions of the proteins and their binding partner in the presence and absence of the ligands, and 5) Performing the molecular dynamics simulations. The pharmacophore groups involved in the LPI were also characterized. Aloin, Genistein, Neoglucobrassicin, and Rutin are our new pipeline candidates for inhibiting PPIs involved in COVID-19. We also propose KPI for drug repositioning studies.Communicated by Ramaswamy H. Sarma.

Natural Immunomodulators Treat the Cytokine Storm in SARS-CoV-2

Recently, the world has been dealing with a destructive global pandemic Coronavirus disease 2019 (COVID-19) infection, since 2020; there were millions of infections and hundreds of thousands of deaths worldwide. With sequencing generations of the virus, around 60% are expected to become infected during the pandemic. Unfortunately, no drug or vaccine has been approved because no real evidence from clinical trials in treatment was reached. According to current thinking, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mortality is caused by a cytokine storm syndrome in patients with hyper-inflammatory conditions, resulting in acute respiratory distress and finally death. In this review, we discuss the various types of natural immune-modulatory agents and their role in the management of SARS-CoV-2, and cytokine storm syndrome. For example, Polyphenols as natural products can block the binding of SARS-CoV-2 spike protein to host cell receptor ACE2, stop viral entry into the host cell and block viral RNA replication. Also, saikosaponins (A, B2, C, and D), triterpene glycosides, which are isolated from medicinal plants exert antiviral action against HCoV-22E9, and Houttuynia cordata water extract has antiviral effects on SARS-CoV. Moreover, eucalyptus oil has promising potential for COVID-19 prevention and treatment. There is an urgent need for research to improve the function of the human immune system all over the world. As a result, actions for better understanding and improving the human immune system are critical steps toward mitigating risks and negative outcomes. These approaches will be strongly recommended for future emerging viruses and pathogens.

Vitisin B inhibits influenza A virus replication by multi-targeting neuraminidase and virus-induced oxidative stress

The development of drug-resistant influenza and new pathogenic virus strains underscores the need for antiviral therapeutics. Currently, neuraminidase (NA) inhibitors are commonly used antiviral drugs approved by the US Food and Drug Administration (FDA) for the prevention and treatment of influenza. Here, we show that vitisin B (VB) inhibits NA activity and suppresses H1N1 viral replication in MDCK and A549 cells. Reactive oxygen species (ROS), which frequently occur during viral infection, increase virus replication by activating the NF-κB signaling pathway, downmodulating glucose-6-phosphate dehydrogenase (G6PD) expression, and decreasing the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant response activity. VB decreased virus-induced ROS generation by increasing G6PD expression and Nrf2 activity, and inhibiting NF-κB translocation to the nucleus through IKK dephosphorylation. In addition, VB reduced body weight loss, increased survival, decreased viral replication and the inflammatory response in the lungs of influenza A virus (IAV)-infected mice. Taken together, our results indicate that VB is a promising therapeutic candidate against IAV infection, complements existing drug limitations targeting viral NA. It modulated the intracellular ROS by G6PD, Nrf2 antioxidant response pathway, and NF-κB signaling pathway. These results demonstrate the feasibility of a multi-targeting drug strategy, providing new approaches for drug discovery against IAV infection.

Antiviral Potential of Traditional Unani Medicine with Special Emphasis on Dengue: A Review

Dengue fever has become a major public health concern. It is usually related to intravascular leaking, bleeding disorders, and thrombocytopenia and is recognized as a potent threat to humans. The scarcity of anti-dengue medication or vaccine for such a serious disease leads to an upsurge in the usage of traditional medicines for its proper management. India has diverse biodiversity and a long history of using plant-based remedies. Several medicinal plant extracts have been studied for producing anti-dengue viral activity. AYUSH traditional systems provide a plethora of plants that have been reported to be useful in the treatment of fever. Single and compound plant- based formulations in natural form have been used in Unani holistic approaches. This review serves as a new approach to illustrate the most recent evidence regarding the antiviral activity of various plants by providing scientific proof and also to validate the traditional formulations as effective treatments in dengue fever for global acceptance.

In silico prediction of natural compounds as potential multi-target inhibitors of structural proteins of SARS-CoV-2

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a colossal loss to human health and lives and has deeply impacted socio-economic growth. Remarkable efforts have been made by the scientific community in containing the virus by successful development of vaccines and diagnostic kits. Initiatives towards drug repurposing and discovery have also been undertaken. In this study, we compiled the known natural anti-viral compounds using text mining of the literature and examined them against four major structural proteins of SARS-CoV-2, namely, spike (S) protein, nucleocapsid (N) protein, membrane (M) protein and envelope (E) protein. Following computational approaches, we identified fangchinoline and versicolactone C as the compounds to exhibit strong binding to the target proteins and causing structural deformation of three structural proteins (N, S and M). We recommend the inhibitory effects of these compounds from our study should be experimentally validated against SARS-CoV-2.Communicated by Ramaswamy H. Sarma.

Tripterin liposome relieves severe acute respiratory syndrome as a potent COVID-19 treatment

For coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), 15-30% of patients are likely to develop COVID-19-related acute respiratory distress syndrome (ARDS). There are still few effective and well-understood therapies available. Novel variants and short-lasting immunity are posing challenges to vaccine efficacy, so finding antiviral and antiinflammatory treatments remains crucial. Here, tripterin (TP), a traditional Chinese medicine, was encapsulated into liposome (TP lipo) to investigate its antiviral and antiinflammatory effects in severe COVID-19. By using two severe COVID-19 models in human ACE2-transgenic (hACE2) mice, an analysis of TP lipo's effects on pulmonary immune responses was conducted. Pulmonary pathological alterations and viral burden were reduced by TP lipo treatment. TP lipo inhibits SARS-CoV-2 replication and hyperinflammation in infected cells and mice, two crucial events in severe COVID-19 pathophysiology, it is a promising drug candidate to treat SARS-CoV-2-induced ARDS.

Role of bioactive compounds in the treatment of hepatitis: A review

Hepatitis causes liver infection leading to inflammation that is swelling of the liver. They are of various types and detrimental to human beings. Natural products have recently been used to develop antiviral drugs against severe viral infections like viral hepatitis. They are usually extracted from herbs or plants and animals. The naturally derived compounds have demonstrated significant antiviral effects against the hepatitis virus and they interfere with different stages of the life cycle of the virus, viral release, replication, and its host-specific interactions. Antiviral activities have been demonstrated by natural products such as phenylpropanoids, flavonoids, xanthones, anthraquinones, terpenoids, alkaloids, aromatics, etc., against hepatitis B and hepatitis C viruses. The recent studies conducted to understand the viral hepatitis life cycle, more effective naturally derived drugs are being produced with a promising future for the treatment of the infection. This review emphasizes the current strategies for treating hepatitis, their shortcomings, the properties of natural products and their numerous types, clinical trials, and future prospects as potential drugs.

Paving New Roads Using Allium sativum as a Repurposed Drug and Analyzing its Antiviral Action Using Artificial Intelligence Technology

Context

The whole universe is facing a coronavirus catastrophe, and prompt treatment for the health crisis is primarily significant. The primary way to improve health conditions in this battle is to boost our immunity and alter our diet patterns. A common bulb veggie used to flavor cuisine is garlic. Compounds in the plant that are physiologically active are present, contributing to its pharmacological characteristics. Among several food items with nutritional value and immunity improvement, garlic stood predominant and more resourceful natural antibiotic with a broad spectrum of antiviral potency against diverse viruses. However, earlier reports have depicted its efficacy in the treatment of a variety of viral illnesses. Nonetheless, there is no information on its antiviral activities and underlying molecular mechanisms.

Objectives

The bioactive compounds in garlic include organosulfur (allicin and alliin) and flavonoid (quercetin) compounds. These compounds have shown immunomodulatory effects and inhibited attachment of coronavirus to the angiotensin-converting enzyme 2 (ACE2) receptor and the Mpro of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Further, we have discussed the contradictory impacts of garlic used as a preventive measure against the novel coronavirus.

Method

The GC/MS analysis revealed 18 active chemicals, including 17 organosulfur compounds in garlic. Using the molecular docking technique, we report for the first time the inhibitory effect of the under-consideration compounds on the host receptor ACE2 protein in the human body, providing a crucial foundation for understanding individual compound coronavirus resistance on the main protease protein of SARS-CoV-2. Allyl disulfide and allyl trisulfide, which make up the majority of the compounds in garlic, exhibit the most potent activity.

Results

Conventional medicine has proven its efficiency from ancient times. Currently, our article's prime spotlight was on the activity of Allium sativum on the relegation of viral load and further highlighted artificial intelligence technology to study the attachment of the allicin compound to the SARS-CoV-2 receptor to reveal its efficacy.

Conclusions

The COVID-19 pandemic has triggered interest among researchers to conduct future research on molecular docking with clinical trials before releasing salutary remedies against the deadly malady.

Tackling the Future Pandemics: Broad-Spectrum Antiviral Agents (BSAAs) Based on A-Type Proanthocyanidins

A-type proanthocyanidins (PAC-As) are plant-derived natural polyphenols that occur as oligomers or polymers of flavan-3-ol monomers, such as (+)-catechin and (-)-epicatechin, connected through an unusual double A linkage. PAC-As are present in leaves, seeds, flowers, bark, and fruits of many plants, and are thought to exert protective natural roles against microbial pathogens, insects, and herbivores. Consequently, when tested in isolation, PAC-As have shown several biological effects, through antioxidant, antibacterial, immunomodulatory, and antiviral activities. PAC-As have been observed in fact to inhibit replication of many different human viruses, and both enveloped and non-enveloped DNA and RNA viruses proved sensible to their inhibitory effect. Mechanistic studies revealed that PAC-As cause reduction of infectivity of viral particles they come in contact with, as a result of their propensity to interact with virion surface capsid proteins or envelope glycoproteins essential for viral attachment and entry. As viral infections and new virus outbreaks are a major public health concern, development of effective Broad-Spectrum Antiviral Agents (BSAAs) that can be rapidly deployable even against future emerging viruses is an urgent priority. This review summarizes the antiviral activities and mechanism of action of PAC-As, and their potential to be deployed as BSAAs against present and future viral infections.

Post-COVID-19 complications in home and hospital-based care: A study from Dhaka city, Bangladesh

A cross-sectional survey was undertaken to understand the management patterns and post-COVID-19 complications among hospital and home-treated participants. Retrospective information was collected from four COVID-19 dedicated hospitals and four selected community settings. Using probability proportional sampling, 925 participants were selected. Data were collected using a semi-structured questionnaire. Bivariate and multivariate logistic regression analysis and the exact chi-square tests were utilized to analyze the association between the studied variables. A total of 659 participants responded (response rate 70.93%); 375 from hospitals and 284 from communities. About 80% of participants were mild cases, 75% were treated at home, and 65% of hospital-treated participants were referred after home treatment. Participants treated at home-to hospital and directly in the hospital had 1.64 and 3.38 times longer recovery time respectively than what home-based participants had. A significant increasing trend (p < 0.001) of co-morbidities was found among referred and hospital treated participants. Age, level of education, physical exercise, practicing preventive measures, exposure to sunlight, and intake of carbohydrate, additional liquid, food supplements, and avoidance of junk foods were significantly associated with place of treatment. Post-COVID-19 difficulties of all factors were statistically significant for home treatment participants, whilst only depression (p = 0.026), chest pain (p = 0.017), and digestive disorders (p = 0.047) were significant (p < 0.05) for hospital treated participants. The outcomes from this study provide insight into a range of post-COVID-19 difficulties relating to at home and in hospital treatment participants. There are clear differences in the complications experienced, many of which are statistically significant. The health care professionals, the community people and COVID-19 survivors will be benefitted from the study findings, and the policy level people may use the information for designing health education program on post COVID-19 complications.

Mulberry Component Kuwanon C Exerts Potent Therapeutic Efficacy In Vitro against COVID-19 by Blocking the SARS-CoV-2 Spike S1 RBD:ACE2 Receptor Interaction

There has been an immense effort by global pharmaceutical companies to develop anti-COVID-19 drugs, including small molecule-based RNA replication inhibitors via drug repositioning and antibody-based spike protein blockers related to cell entry by SARS-CoV-2. However, several limitations to their clinical use have emerged in addition to a lack of progress in the development of small molecule-based cell entry inhibitors from natural products. In this study, we tested the effectiveness of kuwanon C (KC), which has mainly been researched using in silico docking simulation and can serve as an effective building block for developing anti-COVID-19 drugs, in blocking the spike S1 RBD:ACE2 receptor interaction. KC is a natural product derived from Morus alba L., commonly known as mulberry, which has known antiviral efficacy. Molecular interaction studies using competitive ELISA and the BLItz system revealed that KC targets both the spike S1 RBD and the ACE2 receptor, successfully disrupting their interaction, as supported by the in silico docking simulation. Furthermore, we established a mechanism of action by observing how KC prevents the infection of SARS-CoV-2 spike pseudotyped virus in ACE2/TPRSS2-overexpressing HEK293T cells. Finally, we demonstrated that KC inhibits clinical isolates of SARS-CoV-2 in Vero cells. Future combinations of small molecule-based cell entry inhibitors, such as KC, with the currently prescribed RNA replication inhibitors are anticipated to significantly enhance the efficacy of COVID-19 therapies.

Antioxidant, Anti-inflammatory, and Immunomodulatory Roles of Nonvitamin Antioxidants in Anti-SARS-CoV-2 Therapy

Viral pathologies encompass activation of pro-oxidative pathways and inflammatory burst. Alleviating overproduction of reactive oxygen species and cytokine storm in COVID-19 is essential to counteract the immunogenic damage in endothelium and alveolar membranes. Antioxidants alleviate oxidative stress, cytokine storm, hyperinflammation, and diminish the risk of organ failure. Direct antiviral roles imply: impact on viral spike protein, interference with the ACE2 receptor, inhibition of dipeptidyl peptidase 4, transmembrane protease serine 2 or furin, and impact on of helicase, papain-like protease, 3-chyomotrypsin like protease, and RNA-dependent RNA polymerase. Prooxidative environment favors conformational changes in the receptor binding domain, promoting the affinity of the spike protein for the host receptor. Viral pathologies imply a vicious cycle, oxidative stress promoting inflammatory responses, and vice versa. The same was noticed with respect to the relationship antioxidant impairment-viral replication. Timing, dosage, pro-oxidative activities, mutual influences, and interference with other antioxidants should be carefully regarded. Deficiency is linked to illness severity.

In silico evaluation of Philippine Natural Products against SARS-CoV-2 Main Protease

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, is a novel strain of coronavirus first reported in December 2019 which rapidly spread throughout the world and was subsequently declared a pandemic by the World Health Organization (WHO) in March 2020. Although vaccines, as well as treatments, have been rapidly developed and deployed, these are still spread thin, especially in the developing world. There is also a continuing threat of the emergence of mutated variants which may not be as responsive to available vaccines and drugs. Accessible and affordable sources of antiviral drugs against SARS-CoV-2 offer wider options for the clinical treatment of populations at risk for severe COVID-19. Using in silico methods, this study identified potential inhibitors against the SARS-CoV-2 main protease (Mpro), the protease directly responsible for the activation of the viral replication enzyme, from a consolidated database of 1516 Philippine natural products. Molecular docking experiments, along with in silico ADME predictions, determined top ligands from this database with the highest potential inhibitory effects against Mpro. Molecular dynamic trajectories of the apo and diosmetin-7-O-b-D-glucopyranoside (DG) in complex with the protein predicted potential mechanisms of action for the ligand-by separating the Cys145-His41 catalytic dyad and by influencing the protein network through key intra-signaling residues within the Mpro binding site. These findings show the inhibitory potential of DG against the SARS-CoV-2 Mpro, and further validation is recommended through in vitro or in vivo experimentation.

Potential of Azadirachta indica as a Capping Agent for Antiviral Nanoparticles against SARS-CoV-2

A rare type of pneumonia later on referred to as COVID-19 was reported in China in December 2019. Investigations revealed that this disease is caused by a coronavirus previously identified as SARS-CoV-2, and since then, it has become a global pandemic with new strains emerging rapidly as a result of genetic mutations. Various therapeutic options are being explored in order to eradicate this pandemic even though approved vaccine candidates are being currently rolled out globally. Most medicinal plant extracts have astonishing properties, and they can therefore be used in the biosynthesis of effective antiviral nanoparticles. In this systematic review, we aimed to highlight the specific attributes that make Azadirachta indica (neem plant) a suitable candidate for the biosynthesis of anti-SARS-CoV-2 nanoparticles. A systematic investigation was therefore carried out in PubMed, Scopus, Web of Science, and AJOL databases with the keywords "Nanoparticles," "Biosynthesis," "Antivirals," "SARS-CoV-2," and "Azadirachta indica." 1216 articles were retrieved by the 21st of February 2022, but we screened studies that reported data on biomedical and antimicrobial assessment of Azadirachta indica extracts. We also screened studies that were reporting nanoparticles possessing antiviral properties against SARS-C0V-2, narrowing our results to 98 reports. Herein, the SARS-CoV-2 viral structure is briefly discussed with nanoparticles of biomedical importance in the design of SARS-CoV-2 antivirals. Most importantly, we focused on the biomedical and antiviral properties of Azadirachta indica extracts that could be of importance in the design of potential anti-SARS-CoV-2 nanoformulations.

Antiviral perspectives of economically important Indian medicinal plants and spices

Human respiratory diseases caused by viral infections leads to morbidity. Among infectious diseases, viral infections associated with the respiratory tract remain the primary reason for global deaths due to their transmissibility. Since immemorial, traditional Indian medicinal plants, their extracts, and several phytochemicals can treat various diseases. Sources for this review paper are data derived from a peer-reviewed journal that emphasizes the economic importance of medicinal plants. Several plant-based medicines have been reported to be effective against multiple viral infections, including the Human Adenovirus, Enterovirus, Influenza virus, Hepatitis virus, etc. This review emphasizes use of the Indian medicinal plants like as Withania somnifera (Ashwagandha, Winter Cherry), Moringa oleifera (Drumstick), Ocimum tenuiflorum (Tulsi), Azadirachta indica (Neem), Curcuma longa (Turmeric), Terminalia chebula (Chebulic Myrobalan), Punica granatum (Pomegranate) and the Indian household spices (ginger, garlic and black pepper). It further describes their secondary phytoconstituents extraction procedure, mode of action and the potential application to improve clinical outcomes of neutraceuticals against various viral infections.

Integration of the Connectivity Map and Pathway Analysis to Predict Plant Extract’s Medicinal Properties—The Study Case of Sarcopoterium spinosum L

Medicinal properties of plants are usually identified based on knowledge of traditional medicine or using low-throughput screens for specific pharmacological activities. The former is very biased since it requires prior knowledge of plants’ properties, while the latter depends on a specific screening system and will miss medicinal activities not covered by the screen. We sought to enrich our understanding of the biological activities of Sarcopoterium spinosum L. root extract based on transcriptome changes to uncover a plurality of possible pharmacological effects without the need for prior knowledge or functional screening. We integrated Gene Set Enrichment Analysis of the RNAseq data to identify pathways affected by the treatment of cells with the extract and perturbational signatures in the CMAP database to enhance the validity of the results. Activities of signaling pathways were measured using immunoblotting with phospho-specific antibodies. Mitochondrial membrane potential was assessed using JC-1 staining. SARS-CoV-2-induced cell killing was assessed in Vero E6 and A549 cells using an MTT assay. Here, we identified transcriptome changes following exposure of cultured cells to the medicinal plant Sarcopoterium spinosum L. root extract. By integrating algorithms of GSEA and CMAP, we confirmed known anti-cancer activities of the extract and predicted novel biological effects on oxidative phosphorylation and interferon pathways. Experimental validation of these pathways uncovered strong activation of autophagy, including mitophagy, and excellent protection from SARS-CoV-2 infection. Our study shows that gene expression analysis alone is insufficient for predicting biological effects since some of the changes reflect compensatory effects, and additional biochemical tests provide necessary corrections. This study defines the advantages and limitations of transcriptome analysis in predicting the biological and medicinal effects of the Sarcopoterium spinosum L. extract. Such analysis could be used as a general approach for predicting the medicinal properties of plants.

In silico investigation and potential therapeutic approaches of natural products for COVID-19: Computer-aided drug design perspective

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a substantial number of deaths around the world, making it a serious and pressing public health hazard. Phytochemicals could thus provide a rich source of potent and safer anti-SARS-CoV-2 drugs. The absence of approved treatments or vaccinations continues to be an issue, forcing the creation of new medicines. Computer-aided drug design has helped to speed up the drug research and development process by decreasing costs and time. Natural compounds like terpenoids, alkaloids, polyphenols, and flavonoid derivatives have a perfect impact against viral replication and facilitate future studies in novel drug discovery. This would be more effective if collaboration took place between governments, researchers, clinicians, and traditional medicine practitioners' safe and effective therapeutic research. Through a computational approach, this study aims to contribute to the development of effective treatment methods by examining the mechanisms relating to the binding and subsequent inhibition of SARS-CoV-2 ribonucleic acid (RNA)-dependent RNA polymerase (RdRp). The in silico method has also been employed to determine the most effective drug among the mentioned compound and their aquatic, nonaquatic, and pharmacokinetics' data have been analyzed. The highest binding energy has been reported -11.4 kcal/mol against SARS-CoV-2 main protease (7MBG) in L05. Besides, all the ligands are non-carcinogenic, excluding L04, and have good water solubility and no AMES toxicity. The discovery of preclinical drug candidate molecules and the structural elucidation of pharmacological therapeutic targets have expedited both structure-based and ligand-based drug design. This review article will assist physicians and researchers in realizing the enormous potential of computer-aided drug design in the design and discovery of therapeutic molecules, and hence in the treatment of deadly diseases.

Unraveling the multi-targeted curative potential of bioactive molecules against cervical cancer through integrated omics and systems pharmacology approach

Molecular level understanding on the role of viral infections causing cervical cancer is highly essential for therapeutic development. In these instances, systems pharmacology along with multi omics approach helps in unraveling the multi-targeted mechanisms of novel biologically active compounds to combat cervical cancer. The immuno-transcriptomic dataset of healthy and infected cervical cancer patients was retrieved from the array express. Further, the phytocompounds from medicinal plants were collected from the literature. Network Analyst 3.0 has been used to identify the immune genes around 384 which are differentially expressed and responsible for cervical cancer. Among the 87 compounds reported in plants for treating cervical cancer, only 79 compounds were targeting the identified immune genes of cervical cancer. The significant genes responsible for the domination in cervical cancer are identified in this study. The virogenomic signatures observed from cervical cancer caused by E7 oncoproteins serve as the potential therapeutic targets whereas, the identified compounds can act as anti-HPV drug deliveries. In future, the exploratory rationale of the acquired results will be useful in optimizing small molecules which can be a viable drug candidate.

Broad-spectrum antiviral activity of Spatholobus suberectus Dunn against SARS-CoV-2, SARS-CoV-1, H5N1, and other enveloped viruses

The current COVID-19 pandemic caused by SARS-Cov-2 is responsible for more than 6 million deaths globally. The development of broad-spectrum and cost-effective antivirals is urgently needed. Medicinal plants are renowned as a complementary approach in which antiviral natural products have been established as safe and effective drugs. Here, we report that the percolation extract of Spatholobus suberectus Dunn (SSP) is a broad-spectrum viral entry inhibitor against SARS-CoV-1/2 and other enveloped viruses. The viral inhibitory activities of the SSP were evaluated by using pseudotyped SARS-CoV-1 and 2, HIV-1_{ADA and HXB2} , and H5N1. SSP effectively inhibited viral entry and with EC₅₀ values ranging from 3.6 to 5.1 μg/ml. Pre-treatment of pseudovirus or target cells with SSP showed consistent inhibitory activities with the respective EC₅₀ value of 2.3 or 2.1 μg/ml. SSP blocked both SARS-CoV-2 spike glycoprotein and the host ACE2 receptor. In vivo studies indicated that there was no abnormal toxicity and behavior in long-term SSP treatment. Based on these findings, we concluded that SSP has the potential to be developed as a drug candidate for preventing and treating COVID-19 and other emerging enveloped viruses.

(+)-Usnic acid and its salts, inhibitors of SARS-CoV-2, identified by using in silico methods and in vitro assay

The pandemic caused by severe acute respiratory Coronavirus-2 (SARS-CoV-2) has been ongoing for over two years, and treatment for COVID-19, other than monoclonal antibodies, is urgently required. Accordingly, we have investigated the inhibitors of SARS-CoV-2 protein targets by high-throughput virtual screening using a marine natural products database. Considering the calculated molecular properties and availability of the compounds, (+)-usnic acid was selected as a suitable hit. In the in vitro antiviral assay of (+)-usnic acid by the immunofluorescence method, IC₅₀ was 7.99 μM, which is similar to that of remdesivir used as a positive control. The generalized Born and surface area continuum solvation (MM/GBSA) method was performed to find the potent target of (+)-usnic acid, and the Mpro protein showed the most prominent value, -52.05 kcal/mol, among other SARS-CoV-2 protein targets. Thereafter, RMSD and protein-ligand interactions were profiled using molecular dynamics (MD) simulations. Sodium usnate (NaU) improved in vitro assay results with an IC₅₀ of 5.33 μM and a selectivity index (SI) of 9.38. Additionally, when (+)-usnic acid was assayed against SARS-CoV-2 variants, it showed enhanced efficacy toward beta variants with an IC₅₀ of 2.92 μM and SI of 11.1. We report the in vitro anti-SARS-CoV-2 efficacy of (+)-usnic acid in this study and propose that it has the potential to be developed as a COVID-19 treatment if its in vivo efficacy has been confirmed.

The Inhibitory Potential of Ferulic Acid Derivatives against the SARS-CoV-2 Main Protease: Molecular Docking, Molecular Dynamics, and ADMET Evaluation

The main protease (Mpro) of SARS-CoV-2 is an appealing target for the development of antiviral compounds, due to its critical role in the viral life cycle and its high conservation among different coronaviruses and the continuously emerging mutants of SARS-CoV-2. Ferulic acid (FA) is a phytochemical with several health benefits that is abundant in plant biomass and has been used as a basis for the enzymatic or chemical synthesis of derivatives with improved properties, including antiviral activity against a range of viruses. This study tested 54 reported FA derivatives for their inhibitory potential against Mpro by in silico simulations. Molecular docking was performed using Autodock Vina, resulting in comparable or better binding affinities for 14 compounds compared to the known inhibitors N3 and GC376. ADMET analysis showed limited bioavailability but significantly improved the solubility for the enzymatically synthesized hits while better bioavailability and druglikeness properties but higher toxicity were observed for the chemically synthesized ones. MD simulations confirmed the stability of the complexes of the most promising compounds with Mpro, highlighting FA rutinoside and compound e27 as the best candidates from each derivative category.

The Main Protease of SARS-CoV-2 as a Target for Phytochemicals against Coronavirus

In late December 2019, the first cases of COVID-19 emerged as an outbreak in Wuhan, China that later spread vastly around the world, evolving into a pandemic and one of the worst global health crises in modern history. The causative agent was identified as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although several vaccines were authorized for emergency use, constantly emerging new viral mutants and limited treatment options for COVID-19 drastically highlighted the need for developing an efficient treatment for this disease. One of the most important viral components to target for this purpose is the main protease of the coronavirus (Mpro). This enzyme is an excellent target for a potential drug, as it is essential for viral replication and has no closely related homologues in humans, making its inhibitors unlikely to be toxic. Our review describes a variety of approaches that could be applied in search of potential inhibitors among plant-derived compounds, including virtual in silico screening (a data-driven approach), which could be structure-based or fragment-guided, the classical approach of high-throughput screening, and antiviral activity cell-based assays. We will focus on several classes of compounds reported to be potential inhibitors of Mpro, including phenols and polyphenols, alkaloids, and terpenoids.

Essential oil nebulization in mild COVID-19(EONCO): Early phase exploratory clinical trial

Background

Medications studied for therapeutic benefits in coronavirus disease 2019 (COVID-19) have produced inconclusive efficacy results except for steroids.

Objective

A prospective randomized open-label, parallel-arm Phase I/II clinical trial was planned to compare essential oil (EO) blend versus placebo nebulization in mild COVID-19.

Methods

A Phase I safety evaluation was carried out in a single ascending and multiple ascending dose study designs. We assessed Phase II therapeutic efficacy on COVID-19 and general respiratory symptoms on days 0, 3, 5, 7, 10, and 14 on the predesigned case record form. Viremia was evaluated on day 0, day 5, and day 10.

Results

Dose-limiting toxicities were not reached with the doses, frequencies, and duration studied, thus confirming the formulation's preliminary safety. General respiratory symptoms (p < 0.001), anosmia (p < 0.05), and dysgeusia (p < 0.001) benefited significantly with the use of EO blend nebulization compared to placebo. Symptomatic COVID-19 participants with mild disease did not show treatment benefits in terms of symptomatic relief (p = 1.0) and viremia clearance (p = 0.74) compared to the placebo. EO blend was found to be associated with the reduced evolution of symptoms in previously asymptomatic reverse transcription polymerase chain reaction (RT-PCR)-positive study participants (p = 0.034).

Conclusion

EO nebulization appears to be a safer add-on symptomatic relief approach for mild COVID-19. However, the direct antiviral action of the EO blend needs to be assessed with different concentrations of combinations of individual phytochemicals in the EO blend.

Computational studies evidenced the potential of steroidal lactone to disrupt surface interaction of SARS-CoV-2 spike protein and hACE2

The critical event in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pathogenesis is recognition of host cells by the virus, which is facilitated by protein-protein interaction (PPI) of viral Spike-Receptor Binding Domain (S-RBD) and Human Angiotensin Converting Enzyme 2-Receptor (hACE2-R). Thus, disrupting the interaction between S-RBD and hACE2-R is widely accepted as a primary strategy for managing COVID-19. The purpose of this study is to assess the ability of three steroidal lactones (SL) (4-Dehydrowithaferin A, Withaferin A, and Withalongolide A) derived from plants to disrupt the PPI of S-RBD and hACE2-R under two conditions (CON-I and CON-II) using in-silico methods. Under CON-I, 4-Dehydrowithaferin A destabilizing the interactions between S-RBD and hACE2-R, as indicated by an increase in binding energy (BE) from -1028.5 kJ/mol (control) to -896.12 kJ/mol 4-Dehydrowithaferin A exhibited a strong interaction with S-RBD GLY496 with a hydrogen bond occupancy (HBO) of 37.33%. Under CON-II, Withalongolide A was capable of disrupting all types of PPI, as evidenced by an increased BE from -913 kJ/mol (control) to -133.69 kJ/mol and an increased distance (>3.55 nm) between selected AAR combinations of S-RBD and hACE2-R. Withalongolide A formed a hydrogen bond with TYR453 (97%, HBO) of S-RBD, which is required for interaction with hACE2-R's HIS34. Our studies demonstrated that SL molecules have the potential to disrupt the S-RBD and hACE2-R interaction, thereby preventing SARS-CoV-2 from recognizing host cells. The SL molecules can be considered for additional in-vitro and in-vivo studies with this research evidence.

Therapeutic role of traditionally used Indian medicinal plants and spices in combating COVID-19 pandemic situation

The coronavirus disease (COVID-19) caused by SARS-CoV-2 is a big challenge and burning issue to the scientific community and doctors worldwide. Globally, COVID-19 has created a health disaster and adversely affects the economic growth. Although some vaccines have already emerged, no therapeutic medication has yet been approved by FDA for the treatment of COVID-19 patients. Traditionally, we have been using different medicinal plants like neem, tulsi, tea, and many spices like garlic, ginger, turmeric, black seed, onion, etc. for the treatment of flu-like diseases. In this paper, we are highlighting the recent research progress in the identification of natural products from the Indian medicinal plants and spices that have potential inhibition properties against SARS-CoV-2. This study will provide an initiative to stimulate further research by providing useful guidance to the medicinal chemists for designing new protease inhibitors effective against SARS-CoV-2 in future.

Synthesized Magnolol Derivatives Improve Anti-Micropterus salmoides Rhabdovirus (MSRV) Activity In Vivo

Micropterus salmoides rhabdovirus (MSRV) is a primary viral pathogen in largemouth bass aquaculture, which leads to tremendous economic losses yearly. Currently, there are no approved drugs for the treatment and control of this virus. Our previous studies screened the herb Magnolia officinalis from many traditional Chinese medicines, and we isolated and identified magnolol as its main active compound against multiple rhabdoviruses, including MSRV. On the basis of the structure–activity relationship and pharmacophore model of magnolol, two new magnolol derivatives, namely, hydrogenated magnolol and 2,2′-dimethoxy-magnolol, were designed and synthesized. Their anti-MSRV activities were systematically investigated both in vitro and in vivo. By comparing the half-maximal inhibitory concentration (IC₅₀), it was found that hydrogenated magnolol possessed a higher anti-MSRV activity than magnolol and 2,2′-dimethoxy-magnolol, with an IC₅₀ of 13.37 μM. Furthermore, hydrogenated magnolol exhibited a protective effect on the grass carp ovary (GCO) cell line by reducing the cytopathic effect induced by MSRV. Further studies revealed that hydrogenated magnolol did not directly impact virions or interfere with MSRV adsorption. It worked within the 6–8 h of the phase of virus replication. In vivo treatment of MSRV infection with magnolol and hydrogenated magnolol showed that they significantly improved the survival rate by 44.6% and 62.7%, respectively, compared to MSRV-infected groups. The viral load measured by the expression of viral glycoprotein in the organs including the liver, spleen, and kidney also significantly decreased when fish were intraperitoneally injected at a dose of 20 mg/kg. Altogether, the structural optimization of magnolol via hydrogenation of the propylene groups increased its anti-MSRV activity both in vitro and in vivo. These results may provide a valuable reference for anti-MSRV drug discovery and development in aquaculture.

Bergamottin, a bioactive component of bergamot, inhibits SARS-CoV-2 infection in golden Syrian hamsters

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused an ongoing pandemic, coronavirus disease-2019 (COVID-19), which has become a major global public health event. Antiviral compounds remain the predominant means of treating COVID-19. Here, we reported that bergamottin, a furanocoumarin originally found in bergamot, exhibited inhibitory activity against SARS-CoV-2 in vitro, ex vivo, and in vivo. Bergamottin interfered with multiple stages of virus life cycles, specifically blocking the SARS-CoV-2 spike-mediated membrane fusion and effectively reducing viral RNA synthesis. Oral delivery of bergamottin to golden Syrian hamsters at dosages of both 50 mg/kg and 75 mg/kg reduced the SARS-CoV-2 load in nasal turbinates and lung tissues. Pathological damage caused by viral infection was also ameliorated after bergamottin treatment. Overall, our study provides evidence of bergamottin as a promising natural compound, with broad-spectrum anti-coronavirus activity, that could be further developed in the fight against COVID-19 infection during the current pandemic.

Review of Medicinal Plants and Active Pharmaceutical Ingredients against Aquatic Pathogenic Viruses

Aquaculture offers a promising source of economic and healthy protein for human consumption, which can improve wellbeing. Viral diseases are the most serious type of diseases affecting aquatic animals and a major obstacle to the development of the aquaculture industry. In the background of antibiotic-free farming, the development and application of antibiotic alternatives has become one of the most important issues in aquaculture. In recent years, many medicinal plants and their active pharmaceutical ingredients have been found to be effective in the treatment and prevention of viral diseases in aquatic animals. Compared with chemical drugs and antibiotics, medicinal plants have fewer side-effects, produce little drug resistance, and exhibit low toxicity to the water environment. Most medicinal plants can effectively improve the growth performance of aquatic animals; thus, they are becoming increasingly valued and widely used in aquaculture. The present review summarizes the promising antiviral activities of medicinal plants and their active pharmaceutical ingredients against aquatic viruses. Furthermore, it also explains their possible mechanisms of action and possible implications in the prevention or treatment of viral diseases in aquaculture. This article could lay the foundation for the future development of harmless drugs for the prevention and control of viral disease outbreaks in aquaculture.

Bis-Benzylisoquinoline Alkaloids Inhibit Porcine Epidemic Diarrhea Virus In Vitro and In Vivo

Porcine epidemic diarrhea virus (PEDV) belongs to the genus Alphacoronavirus of the family Coronaviridae that causes severe diarrhea and high mortality in neonatal suckling piglets. Currently, there is no effective medication against this pathogen. Cepharanthine (CEP), tetrandrine (TET), and fangchinoline (FAN) are natural bis-benzylisoquinoline alkaloids with anti-inflammatory, antitumor, and antiviral properties. Here, we first found that CEP, TET, and FAN had anti-PEDV activity with IC₅₀ values of 2.53, 3.50, and 6.69 μM, respectively. The compounds could block all the processes of viral cycles, but early application of the compounds before or during virus infection was advantageous over application at a late stage of virus replication. FAN performed inhibitory function more efficiently through interfering with the virus entry and attachment processes or through attenuating the virus directly. CEP had a more notable effect on virus entry. With the highest SI index of 11.8 among the three compounds, CEP was chosen to carry out animal experiments. CEP in a safe dosage of 11.1 mg/kg of body weight could reduce viral load and pathological change of piglet intestinal tracts caused by PEDV field strain challenge, indicating that CEP efficiently inhibited PEDV infection in vivo. All of these results demonstrated that the compounds of bis-benzylisoquinoline alkaloids could inhibit PEDV proliferation efficiently and had the potential of being developed for PED prevention and treatment.

Antiviral Activity of Medicinal Plants against Human Coronavirus: a systematic scoping review of and experimentations

OBJECTIVE

To investigate the and studies of natural compounds and medicinal plants with anti-coronavirus activity.

METHODS

A systematic review was performed based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Animal Research: Reporting of experiments guidelines to find data for medicinal plants and natural products effective against human coronaviruses in or studies. Studies published up to September 6, 2020 were included. Studies ( or ) reporting the effect of medicinal plants and natural products or their derivatives on human coronavirus were included RESULTS: Promising anti-coronavirus effects are seen with different herbal compounds like some diterpenoids, sesquiterpenoids, and three compounds in tea with 3CLpro inhibiting effect of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV); Hirsutenone, Six cinnamic amides and bavachinin are PLpro inhibitors and Tanshinones are active on both 3CLpro and PLpro. Some flavonoid compounds of Citrus fruits act on Immun-oregulation and target angiotensin-converting enzyme 2 which is used by SARS-COV for entry. Virus helicase is possibly inhibited by two compounds myricetin and scutellarein.

CONCLUSION

This review shows that complementary medicine have the potential for new drug discovery against coronavirus. Further research is needed before definitive conclusions can be made concerning the safety and efficacy of the use of these medicinal plants.

Multidimensional in silico strategy for identification of natural polyphenols-based SARS-CoV-2 main protease (Mpro) inhibitors to unveil a hope against COVID-19

SARS-CoV-2, a rapidly spreading new strain of human coronavirus, has affected almost all the countries around the world. The lack of specific drugs against SARS-CoV-2 is a significant hurdle towards the successful treatment of COVID-19. Thus, there is an urgent need to boost up research for the development of effective therapeutics against COVID-19. In the current study, we investigated the efficacy of 81 medicinal plant-based bioactive compounds against SARS-CoV-2 M^pro by using various in silico techniques. The interaction affinities of polyphenolic compounds towards SARS-CoV-2 M^pro was assessed via intramolecular (by Quantum Mechanic), intermolecular (by Molecular Docking), and spatial (by Molecular Dynamic) simulations. Our obtained result demonstrate that Hesperidin, rutin, diosmin, and apiin are most effective compounds agents against SARS-CoV-2 Mpro as compared to Nelfinavir (positive control). This study will hopefully pave a way for advanced experimental research to evaluate the in vitro and in vivo efficacy of these compounds for the treatment of COVID-19.

West African medicinal plants and their constituent compounds as treatments for viral infections, including SARS-CoV-2/COVID-19

OBJECTIVES

The recent emergence of the COVID-19 pandemic (caused by SARS-CoV-2) and the experience of its unprecedented alarming toll on humanity have shone a fresh spotlight on the weakness of global preparedness for pandemics, significant health inequalities, and the fragility of healthcare systems in certain regions of the world. It is imperative to identify effective drug treatments for COVID-19. Therefore, the objective of this review is to present a unique and contextualised collection of antiviral natural plants or remedies from the West African sub-region as existing or potential treatments for viral infections, including COVID-19, with emphasis on their mechanisms of action.

EVIDENCE ACQUISITION

Evidence was synthesised from the literature using appropriate keywords as search terms within scientific databases such as Scopus, PubMed, Web of Science and Google Scholar.

RESULTS

While some vaccines and small-molecule drugs are now available to combat COVID-19, access to these therapeutic entities in many countries is still quite limited. In addition, significant aspects of the symptomatology, pathophysiology and long-term prognosis of the infection yet remain unknown. The existing therapeutic armamentarium, therefore, requires significant expansion. There is evidence that natural products with antiviral effects have been used in successfully managing COVID-19 symptoms and could be developed as anti-COVID-19 agents which act through host- and virus-based molecular targets.

CONCLUSION

Natural products could be successfully exploited for treating viral infections/diseases, including COVID-19. Strengthening natural products research capacity in developing countries is, therefore, a key strategy for reducing health inequalities, improving global health, and enhancing preparedness for future pandemics.

Bioactive Compounds from Plants and their Immune Potential against Corona Virus

Background:

Corona virus is a contagious single-strand RNA virus affecting majorly the lungs causing severe acute respiratory disease. The viral pandemic has affected the world economy and posed new challenges to the scientific community. Due to high mutation rate, a lot of variants are occurring and persons who are vaccinated are also getting affected. In addition, vaccination trials for children aged below 18 are still going on. Moreover, the cost, shelf-life, success rate, no booster dose required, and the long-term complications associated with the vaccine are yet to be studied. Preservation and transportation of vaccines are another big challenge.

Objective:

Despite vaccination, the best alternative is to boost our immune system by administration of bioactive compounds which are safe and effective. Bioactive compounds have been found to be effective against several viral infections.

Methods:

Literature review has been performed using recently published research and review articles pertaining to the role of plant-derived bioactive compounds in regulating COVID-19 infection.

Result:

The current review will describe the role and mechanism of bioactive compounds derived from natural sources in disease management and boosting the immune system against COVID-19.

Conclusion:

In addition to vaccination, the administration of plant-derived bioactive compounds will help in regulating viral infection and boosting the immune response during COVID-19 infection.

Medicinal plants with anti-SARS-CoV activity repurposing for treatment of COVID-19 infection: A systematic review and meta-analysis

The novel SARS-CoV-2 (severe acute respiratory syndrome coronavirus) has emerged as a significant threat to public health with startling drawbacks in all sectors globally. This study investigates the practicality of some medicinal plants for SARS-CoV-2 therapy using a systematic review and meta-analysis of their reported SARS-CoV-1 inhibitory potencies. Relevant data were systematically gathered from three databases, viz., Web of Science, PubMed and Scopus. The information obtained included botanical information, extraction method and extracts concentrations, as well as the proposed mechanisms. Fourteen articles describing 30 different plants met our eligibility criteria. Random effects model and subgroup analysis were applied to investigate heterogeneity. According to subgroup analysis, the substantial heterogeneity of the estimated mean based on the IC ₅₀ values reporting the most potent anti-SARS-CoV 3C--like protease (3CLpro) inhibitors (10.07 %, p < 0.0001), was significantly higher compared to the most active anti-SARS-CoV papain-like protease (PLpro) inhibitors (6.12 %, p < 0.0001). More importantly, the literature analysis revealed that fruit extracts of Rheum palmatum L. and the compound cryptotanshinone isolated from the root of Salvia miltiorrhiza (IC ₅₀ = 0.8 ± 0.2 μmol L^-1) were excellent candidates for anti--SARS-CoV targeting PLpro. Meanwhile, iguesterin (IC ₅₀ = 2.6 ± 0.6 μmol L^-1) isolated from the bark of Tripterygium regelii emerged as the most excellent candidate for anti-SARS--CoV targeting 3CLpro. The present systematic review and meta-analysis provide valuable and comprehensive information about potential medicinal plants for SARS-CoV-2 inhibition. The chemotypes identified herein can be adopted as a starting point for developing new drugs to contain the novel virus.

Comprehensive Review on Applications of Surfactants in Vaccine Formulation, Therapeutic and Cosmetic Pharmacy and Prevention of Pulmonary Failure due to COVID-19

Our world is under serious threat of environmental degradation, climate change and in association with this the out breaks of diseases as pandemics. The devastating impact of the very recent COVID-19, The sharp increase in cases of Cancer, Pulmonary failure, Heart health has triggered questions for the sustainable development of pharmaceutical and medical sciences. In the search of inclusive and effective strategies to meet today’s demand, improvised methodologies and alternative green chemical, bio-based precursors are being introduced by scientists around the globe. In this extensive review we have presented the potentiality and Realtime applications of both synthetic and bio-based surfactants in bio-medical and pharmaceutical fields. For their excellent unique amphoteric nature and ability to solubilise in both organic and inorganic drugs, surfactants are one of the most potential candidates for bio-medicinal fields such as dermatology, drug delivery, anticancer treatment, surfactant therapy, vaccine formulation, personal hygiene care and many more. The self-assembly property of surfactants is a very powerful function for drug delivery systems that increases the bio-availability of the poorly aqueous soluble pharmaceutical products by influencing their solubility. Over the decades many researchers have reported the antimicrobial, anti-adhesive, antibiofilm, anti-inflammatory, antioxidant activities of surfactants regarding its utility in medicinal purposes. In some reports surfactants are found to have spermicidal and laxative activity too. This comprehensive report is targeted to enlighten the versatile applications of Surfactants in drug delivery, vaccine formulation, Cancer Treatment, Therapeutic and cosmetic Pharmaceutical Sciences and prevention of pulmonary failure due to COVID-19.

Point-specific interactions of isovitexin with the neighboring amino acid residues of the hACE2 receptor as a targeted therapeutic agent in suppressing the SARS-CoV-2 influx mechanism

Objective:

Despite the development of several vaccines against severe acute respiratory syndrome coronavirus-2, the need for an additional prophylactic agent is evident. In recent in silico studies, isovitexin exhibited a higher binding affinity against the human angiotensin converting-enzyme 2 (hACE2) receptor than existing antiviral drugs. The research aimed to find out the point specificity of isovitexin for the hACE2 receptor and to assess its therapeutic potential, depending on the stability of the isovitexin–hACE2 complex.

Materials and Methods:

The pharmacokinetic profile of isovitexin was analyzed. The crystal structure of the hACE2 receptor and the ligand isovitexin were docked to form a ligand–protein complex following molecular optimization. To determine the isovitexin–hACE2 complex stability, their binding affinity, hydrogen bonding, and hydrophobic interactions were studied. Lastly, the root mean square deviation (RMSD), root mean square fluctuation, solvent accessible surface area, molecular surface area, radius of gyration (Rg), polar surface area, and principal component analysis values were found by simulating the complex with molecular dynamic (MD).

Results:

The predicted Lethal dose₅₀ for isovitexin was 2.56 mol/kg, with an acceptable maximum tolerated dose and no hepatotoxicity or AMES toxicity. Interactions with the amino acid residues Thr371, Asp367, Glu406, Pro346, His345, Phe274, Tyr515, Glu375, Thr347, Glu402, and His374 of the hACE2 protein were required for the high binding affinity and specificity of isovitexin. Based on what was learned from the MD simulation, the hACE2 receptor-blocking properties of isovitexin were looked at.

Conclusions:

Isovitexin is a phytochemical with a reasonable bioactivity and safety profile for use in humans, and it can potentially be used as a hACE2-specific therapeutic to inhibit COVID-19 infection.

Role of Diet and Nutrients in SARS-CoV-2 Infection: Incidence on Oxidative Stress, Inflammatory Status and Viral Production

Coronavirus illness (COVID-19) is an infectious pathology generated by intense severe respiratory syndrome coronavirus 2 (SARS-CoV-2). This infectious disease has emerged in 2019. The COVID-19-associated pandemic has considerably affected the way of life and the economy in the world. It is consequently crucial to find solutions allowing remedying or alleviating the effects of this infectious disease. Natural products have been in perpetual application from immemorial time given that they are attested to be efficient towards several illnesses without major side effects. Various studies have shown that plant extracts or purified molecules have a promising inhibiting impact towards coronavirus. In addition, it is substantial to understand the characteristics, susceptibility and impact of diet on patients infected with COVID-19. In this review, we recapitulate the influence of extracts or pure molecules from medicinal plants on COVID-19. We approach the possibilities of plant treatment/co-treatment and feeding applied to COVID-19. We also show coronavirus susceptibility and complications associated with nutrient deficiencies and then discuss the major food groups efficient on COVID-19 pathogenesis. Then, we covered emerging technologies using plant-based SARS-CoV-2 vaccine. We conclude by giving nutrient and plants curative therapy recommendations which are of potential interest in the COVID-19 infection and could pave the way for pharmacological treatments or co-treatments of COVID-19.

Thiazole-based SARS-CoV-2 protease (COV Mpro ) inhibitors: Design, synthesis, enzyme inhibition, and molecular modeling simulations

As an attempt to contribute to the efforts of combating the pandemic virus severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) responsible for COVID‐19, new analogs of the repurposed drug nitazoxanide which showed promising inhibitory efficacy on a viral protease enzyme were designed, synthesized and evaluated for their inhibitory activity on the main protease of the SARS‐CoV‐2 virus, using the COV2‐3CL protease inhibition assay. The obtained results showed that the N‐(substituted‐thiazol‐2‐yl)cinnamamide analogs 19, 20, and 21 were the most active compounds with IC₅₀ values of 22.61, 14.7, 21.99 µM, respectively, against the viral protease compared to the reference drugs, nitazoxanide, and lopinavir. Molecular modeling studies showed binding interactions of 19, 20, and 21 with hydrogen bonds to Gln189 and Glu166, arene–arene interaction between the thiazole moiety and His41, and other hydrophobic interactions between the ethene spacer moiety and Asn142. Moreover, an extra arene–arene interaction between substituted benzo[d]thiazole and His41 was observed regarding compounds 19 and 21. Surface mapping and flexible alignment proved the structural similarity between the new drug candidates and nitazoxanide. Compliance of the new compounds to Lipinski's rule of five was investigated and absorption, distribution, metabolism, excretion, and toxicology data were predicted. The newly synthesized compounds are promising template ligands for further development and optimization.

Olive Leaves as a Potential Phytotherapy in the Treatment of COVID-19 Disease; A Mini-Review

Beginning from December 2019, widespread COVID-19 has caused huge financial misfortunes and exceptional wellbeing emergencies across the globe. Discovering an effective and safe drug candidate for the treatment of COVID-19 and its associated symptoms became an urgent global demand, especially due to restricted information that has been discharged with respect to vaccine efficacy and safety in humans. Reviewing the recent research, olive leaves were selected as a potential co-therapy supplement for the treatment and improvement of clinical manifestations in COVID-19 patients. Olive leaves were reported to be rich in phenolic compounds such as oleuropein, hydroxytyrosol, verbascoside, apigenin-7-O-glucoside, and luteolin-7-O-glucoside and also triterpenoids such as maslinic, ursolic, and oleanolic acids that have been reported as anti-SARS-CoV-2 metabolites in recent computational and in vitro studies. In addition, olive leaf extract was previously reported in several in vivo studies for its anti-inflammatory, analgesic, antipyretic, immunomodulatory, and antithrombotic activities which are of great benefit in the control of associated inflammatory cytokine storm and disseminated intravascular coagulation in COVID-19 patients. In conclusion, the described biological activities of olive leaves alongside their biosafety, availability, and low price make them a potential candidate drug or supplement to control COVID-19 infection and are recommended for clinical investigation.

Novel Antiviral Activity of Ethyl 3-Hydroxyhexanoate Against Coxsackievirus B Infection

Coxsackievirus group B (CVB) is a member of the genus Enterovirus in the family Picornaviridae. CVB infection has been implicated as a major etiologic agent of viral myocarditis, dilated cardiomyopathy, meningitis, and pancreatitis among children and young adults. Until date, no antiviral agent has been licensed for the treatment of Coxsackievirus infection. In an effort to identify antiviral agents against diseases caused by the CVB, we found that ethyl 3-hydroxyhexanoate (EHX), a volatile compound present in fruits and food additives, is a potent antiviral compound. In this study, we demonstrated that EHX treatment significantly inhibits CVB replication both in vivo and in vitro. Furthermore, EHX possesses antiviral activity at 50% effective concentration (EC₅₀) of 1.2 μM and 50% cytotoxicity (CC₅₀) of 25.6 μM, yielding a selective index (SI) value as high as 20.8. Insights into the mechanism of antiviral activity of EHX showed that it acts at the step of viral RNA replication. Since EHX has received approval as food additives, treatment of CVB-related infections with EHX might be a safe therapeutic option and may be a promising strategy for the development of semi-synthetic antiviral drugs for viral diseases.

Bioactive Based Nanocarriers for the Treatment of Viral Infections and SARS-CoV-2

Since ancient times, plants have been used for their medicinal properties. They provide us with many phytomolecules, which serve a synergistic function for human well-being. Along with anti-microbial, plants also possess anti-viral activities. In Western nations, about 50% of medicines were extracted from plants or their constituents. The spread and pandemic of viral diseases are becoming a major threat to public health and a burden on the financial prosperity of communities worldwide. In recent years, SARS-CoV-2 has made a dramatic lifestyle change. This has promoted scientists not to use synthetic anti-virals, such as protease inhibitors, nucleic acid analogs, and other anti-virals, but to study less toxic anti-viral phytomolecules. An emerging approach includes searching for eco-friendly therapeutic molecules to develop phytopharmaceuticals. This article briefly discusses numerous bioactive molecules that possess anti-viral properties, their mode of action, and possible applications in treating viral diseases, with a special focus on coronavirus and various nano-formulations used as a carrier for the delivery of phytoconstituents for improved bioavailability.

Target prediction, computational identification, and network-based pharmacology of most potential phytoconstituent in medicinal leaves of Justicia adhatoda against SARS-CoV-2

The current global epidemic of the novel coronavirus (SARS-CoV-2) has been labeled a global public health emergency since it is causing substantial morbidity and mortality on daily basis. We need to identify an effective medication against SARS-CoV-2 because of its fast dissemination and re-emergence. This research is being carried out as part of a larger strategy to identify the most promising therapeutic targets using protein-protein interactions analysis. Mpro has been identified as one of the most important therapeutic targets. In this study, we did in-silico investigations to identify the target and further molecular docking, ADME, and toxicity prediction were done to assess the potential phyto-active antiviral compounds from Justicia adhatoda as powerful inhibitors of the Mpro of SARS-COV-2. We also investigated the capacity of these molecules to create stable interactions with the Mpro using 100 ns molecular dynamics simulation. The highest scoring compounds (taraxerol, friedelanol, anisotine, and adhatodine) were also found to exhibit excellent solubility and pharmacodynamic characteristics. We employed MMPBSA simulations to assess the stability of docked molecules in the Mpro binding site, revealing that the above compounds form the most stable complex with the Mpro. Network-based Pharmacology suggested that the selected compounds have various modes of action against SARS-CoV-2 that include immunoreaction enrichment, inflammatory reaction suppression, and more. These findings point to a promising class of drugs that should be investigated further in biochemical and cell-based studies to see their effectiveness against nCOVID-19.Communicated by Ramaswamy H. Sarma.