Therapeutic potential of medicinal plants against COVID-19: The role of antiviral medicinal metabolites

The Potential of Anti-coronavirus Plant Secondary Metabolites in COVID-19 Drug Discovery as an Alternative to Repurposed Drugs: A Review

In early 2020, a global pandemic was announced due to the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), known to cause COVID-19. Despite worldwide efforts, there are only limited options regarding antiviral drug treatments for COVID-19. Although vaccines are now available, issues such as declining efficacy against different SARS-CoV-2 variants and the aging of vaccine-induced immunity highlight the importance of finding more antiviral drugs as a second line of defense against the disease. Drug repurposing has been used to rapidly find COVID-19 therapeutic options. Due to the lack of clinical evidence for the therapeutic benefits and certain serious side effects of repurposed antivirals, the search for an antiviral drug against SARS-CoV-2 with fewer side effects continues. In recent years, numerous studies have included antiviral chemicals from a variety of plant species. A better knowledge of the possible antiviral natural products and their mechanism against SARS-CoV-2 will help to develop stronger and more targeted direct-acting antiviral agents. The aim of the present study was to compile the current data on potential plant metabolites that can be investigated in COVID-19 drug discovery and development. This review represents a collection of plant secondary metabolites and their mode of action against SARS-CoV and SARS-CoV-2.

Nigella sativa and its chemical constituents: pre-clinical and clinical evidence for their potential anti-SARS-CoV-2 effects

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused over 500 million reported cases of COVID-19 worldwide with relatively high morbidity and mortality. Although global vaccination drive has helped control the pandemic, the newer variant of the virus still holds the world in ransom. Several medicinal herbs with antiviral properties have been reported, and one such promising herb is Nigella sativa (NS). Recent molecular docking, pre-clinical, and clinical studies have shown that NS extracts may have the potential to prevent the entry of coronaviruses into the host cell as well as to treat and manage COVID-19 symptoms. Several active compounds from NS, such as nigelledine, α-hederin, dithymoquinone (DTQ), and thymoquinone (TQ), have been proposed as excellent ligands to target angiotensin-converting enzyme 2 (ACE2 receptors) and other targets on host cells as well as the spike protein (S protein) on SARS-CoV-2. By binding to these target proteins, these ligands could potentially prevent the binding between ACE2 and S protein. Though several articles have been published on the promising therapeutic role of NS and its constituents against SARS-CoV-2 infection, in this review, we consolidate the published information on NS and SARS-CoV-2, focusing on pre-clinical in silico studies as well as clinical trials reported between 2012 and 2023.

Silicone-geranium essential oil blend for long-term antifouling coatings

This study explores the potential of geranium essential oil as a natural solution for combating marine biofouling, addressing the environmental concerns associated with commercial antifouling coatings. Compounds with bactericidal activities were identified by 13Carbon nuclear magnetic resonance (13C NMR). Thermogravimetric analysis (TGA) revealed minimal impact on film thermal stability, maintaining suitability for antifouling applications. The addition of essential oil induced changes in the morphology of the film and Fourier transform infrared spectroscopy (FTIR) analysis indicated that oil remained within the film. Optical microscopy showed an increase in coating porosity after immersion in a marine environment. A total of 18 bacterial colonies were isolated, with Psychrobacter adeliensis and Shewanella algidipiscicola being the predominant biofilm-forming species. The geranium essential oil-based coating demonstrated the ability to reduce the formation of Psychrobacter adeliensis biofilms and effectively inhibit macrofouling adhesion for a duration of 11 months.

Investigation of Epilobium hirsutum L. Optimized Extract's Anti-Inflammatory and Antitumor Potential

Epilobium hirsutum L., commonly known as hairy willowherb, is a perennial herbaceous plant native to Europe and Asia. In Romania, the Epilobium genus includes 17 species that are used in folk medicine for various purposes. This study aimed to investigate the anti-inflammatory and antitumor potential of the optimized extract of Epilobium hirsutum (EH) in animal models. The first study investigated the anti-inflammatory properties of EH optimized extract and the model used was carrageenan-induced paw inflammation. Wistar rats were divided into three groups: negative control, positive control treated with indomethacin, and a group treated with the extract. Oxidative stress markers, cytokine levels, and protein expressions were assessed. The extract demonstrated anti-inflammatory properties comparable to those of the control group. In the second study, the antitumor effects of the extract were assessed using the tumor model of Ehrlich ascites carcinoma. Swiss albino mice with Ehrlich ascites were divided into four groups: negative, positive treated with cyclophosphamide (Cph), Group 3 treated with Cph and EH optimized extract, and Group 4 treated with extract alone. Samples from the ascites fluid, liver, and heart were analyzed to evaluate oxidative stress, inflammation, and cancer markers. The extract showed a reduction in tumor-associated inflammation and oxidative stress. Overall, the EH optimized extract exhibited promising anti-inflammatory and antitumor effects in the animal models studied. These findings suggest its potential as a natural adjuvant therapeutic agent for addressing inflammation and oxidative stress induced by different pathologies.

Repurposing of Plant-based Antiviral Molecules for the Treatment of COVID-19

COVID-19, stemming from SARS-CoV-2, poses a formidable threat to global healthcare, with a staggering 77 million confirmed cases and 690,067 deaths recorded till December 24, 2023. Given the absence of specific drugs for this viral infection, the exploration of novel antiviral compounds becomes imperative. High-throughput technologies are actively engaged in drug discovery, and there is a parallel effort to repurpose plant-based molecules with established antiviral properties. In this context, the review meticulously delves into the potential of plant-based folk remedies and existing molecules. These substances have showcased substantial viral inhibition in diverse in vivo, in silico, and in vitro studies, particularly against critical viral protein targets, including SARS-CoV-2. The findings position these plant-based molecules as promising antiviral drug candidates for the swift advancement of treatments for COVID-19. It is noteworthy that the inherent attributes of these plant-based molecules, such as their natural origin, potency, safety, and cost-effectiveness, contribute to their appeal as lead candidates. The review advocates for further exploration through comprehensive in vivo studies conducted on animal models, emphasizing the potential of plant-based compounds to help in the ongoing quest to develop effective antivirals against COVID-19.

Plant-Derived Epi-Nutraceuticals as Potential Broad-Spectrum Anti-Viral Agents

Although the COVID-19 pandemic appears to be diminishing, the emergence of SARS-CoV-2 variants represents a threat to humans due to their inherent transmissibility, immunological evasion, virulence, and invulnerability to existing therapies. The COVID-19 pandemic affected more than 500 million people and caused over 6 million deaths. Vaccines are essential, but in circumstances in which vaccination is not accessible or in individuals with compromised immune systems, drugs can provide additional protection. Targeting host signaling pathways is recommended due to their genomic stability and resistance barriers. Moreover, targeting host factors allows us to develop compounds that are effective against different viral variants as well as against newly emerging virus strains. In recent years, the globe has experienced climate change, which may contribute to the emergence and spread of infectious diseases through a variety of factors. Warmer temperatures and changing precipitation patterns can increase the geographic range of disease-carrying vectors, increasing the risk of diseases spreading to new areas. Climate change may also affect vector behavior, leading to a longer breeding season and more breeding sites for disease vectors. Climate change may also disrupt ecosystems, bringing humans closer to wildlife that transmits zoonotic diseases. All the above factors may accelerate the emergence of new viral epidemics. Plant-derived products, which have been used in traditional medicine for treating pathological conditions, offer structurally novel therapeutic compounds, including those with anti-viral activity. In addition, plant-derived bioactive substances might serve as the ideal basis for developing sustainable/efficient/cost-effective anti-viral alternatives. Interest in herbal antiviral products has increased. More than 50% of approved drugs originate from herbal sources. Plant-derived compounds offer diverse structures and bioactive molecules that are candidates for new drug development. Combining these therapies with conventional drugs could improve patient outcomes. Epigenetics modifications in the genome can affect gene expression without altering DNA sequences. Host cells can use epigenetic gene regulation as a mechanism to silence incoming viral DNA molecules, while viruses recruit cellular epitranscriptomic (covalent modifications of RNAs) modifiers to increase the translational efficiency and transcript stability of viral transcripts to enhance viral gene expression and replication. Moreover, viruses manipulate host cells' epigenetic machinery to ensure productive viral infections. Environmental factors, such as natural products, may influence epigenetic modifications. In this review, we explore the potential of plant-derived substances as epigenetic modifiers for broad-spectrum anti-viral activity, reviewing their modulation processes and anti-viral effects on DNA and RNA viruses, as well as addressing future research objectives in this rapidly emerging field.

Promising role of Vitamin D and plant metabolites against COVID-19: Clinical trials review

Vitamin D possesses immunomodulatory qualities and is protective against respiratory infections. Additionally, it strengthens adaptive and cellular immunity and boosts the expression of genes involved in oxidation. Experts suggested taking vitamin D supplements to avoid and treat viral infection and also COVID-19, on the other hand, since the beginning of time, the use of plants as medicines have been vital to human wellbeing. The WHO estimates that 80 % of people worldwide use plants or herbs for therapeutic purposes. Secondary metabolites from medicinal plants are thought to be useful in lowering infections from pathogenic microorganisms due to their ability to inhibit viral protein and enzyme activity by binding with them. As a result, this manuscript seeks to describe the role of vitamin D and probable plant metabolites that have antiviral activities and may be complementary to the alternative strategy against COVID-19 in a single manuscript through reviewing various case studies.

Demonstration of the impact of COVID-19 on metabolic associated fatty liver disease by bioinformatics and system biology approach

BACKGROUND

Severe coronavirus disease 2019 (COVID-19) has caused a great threat to human health. Metabolic associated fatty liver disease (MAFLD) is a liver disease with a high prevalence rate. Previous studies indicated that MAFLD led to increased mortality and severe case rates of COVID-19 patients, but its mechanism remains unclear.

METHODS

This study analyzed the transcriptional profiles of COVID-19 and MAFLD patients and their respective healthy controls from the perspectives of bioinformatics and systems biology to explore the underlying molecular mechanisms between the 2 diseases. Specifically, gene expression profiles of COVID-19 and MAFLD patients were acquired from the gene expression omnibus datasets and screened shared differentially expressed genes (DEGs). Gene ontology and pathway function enrichment analysis were performed for common DEGs to reveal the regulatory relationship between the 2 diseases. Besides, the hub genes were extracted by constructing a protein-protein interaction network of shared DEGs. Based on these hub genes, we conducted regulatory network analysis of microRNA/transcription factors-genes and gene - disease relationship and predicted potential drugs for the treatment of COVID-19 and MAFLD.

RESULTS

A total of 3734 and 589 DEGs were screened from the transcriptome data of MAFLD (GSE183229) and COVID-19 (GSE196822), respectively, and 80 common DEGs were identified between COVID-19 and MAFLD. Functional enrichment analysis revealed that the shared DEGs were involved in inflammatory reaction, immune response and metabolic regulation. In addition, 10 hub genes including SERPINE1, IL1RN, THBS1, TNFAIP6, GADD45B, TNFRSF12A, PLA2G7, PTGES, PTX3 and GADD45G were identified. From the interaction network analysis, 41 transcription factors and 151 micro-RNAs were found to be the regulatory signals. Some mental, Inflammatory, liver diseases were found to be most related with the hub genes. Importantly, parthenolide, luteolin, apigenin and MS-275 have shown possibility as therapeutic agents against COVID-19 and MAFLD.

CONCLUSION

This study reveals the potential common pathogenesis between MAFLD and COVID-19, providing novel clues for future research and treatment of MAFLD and severe acute respiratory syndrome coronavirus 2 infection.

Phytochemical Profiling, Antimicrobial, Antiproliferative and Apoptotic Effects of Stemodia viscosa Roxb. of Western Ghats Region, India

The present study shows the chemical profile, antimicrobial, antiproliferative, and apoptotic effects of Stemodia viscosa extracts. Thirteen bioactive compounds were identified in the 80 % ethanolic extract by GC/MS analysis. The acetone extract exhibited a higher content of flavonoids and phenols of 805.10 μg QE/mg DW and 89.31 μg GAE/mg DW extracts, respectively. Furthermore, the acetone extract possessed the highest antioxidant activity (IC50 =9.96 μg/mL). The 80 % ethanolic extract exhibited significant antimicrobial activity; the highest activity was observed against Staphylococcus aureus with a zone of inhibition of 25±0.51 mm, MIC value of 4 mg/mL, and MBC value of 8 mg/mL. The antiproliferative results revealed the presence of anticancer activity with an IC50 =91.562 and 74.362 μg/mL against the B16F10 skin and COLO205 colon cancer cells, respectively. The flow cytometric analysis shows that the plant extracts cause cancer cell death through the induction of apoptosis. Our findings confirmed that Stemodia viscosa is a potential source of biologically active compounds.

Synergistic antiviral activity of Lactobacillus acidophilus and Glycyrrhiza glabra against Herpes Simplex-1 Virus (HSV-1) and Vesicular Stomatitis Virus (VSV): experimental and In Silico insights

BACKGROUND

The emergence of different viral infections calls for the development of new, effective, and safe antiviral drugs. Glycyrrhiza glabra is a well-known herbal remedy possessing antiviral properties.

OBJECTIVE

The objective of our research was to evaluate the effectiveness of a newly developed combination of the probiotics Lactobacillus acidophilus and G. glabra root extract against two viral models, namely the DNA virus Herpes simplex virus-1 (HSV-1) and the RNA virus Vesicular Stomatitis Virus (VSV), with regards to their antiviral properties.

METHODOLOGY

To examine the antiviral impacts of various treatments, we employed the MTT assay and real-time PCR methodology.

RESULTS

The findings of our study indicate that the co-administration of L. acidophilus and G. glabra resulted in a significant improvement in the survival rate of Vero cells, while also leading to a reduction in the titers of Herpes Simplex Virus Type 1 (HSV-1) and Vesicular Stomatitis Virus (VSV) in comparison to cells that were not treated. Additionally, an investigation was conducted on glycyrrhizin, the primary constituent of G. glabra extract, utilizing molecular docking techniques. The results indicated that glycyrrhizin exhibited a greater binding energy score for HSV-1 polymerase (- 22.45 kcal/mol) and VSV nucleocapsid (- 19.77 kcal/mol) in comparison to the cocrystallized ligand (- 13.31 and - 11.44 kcal/mol, respectively).

CONCLUSIONS

The combination of L. acidophilus and G. glabra extract can be used to develop a new, natural antiviral agent that is safe and effective.

Phytochemical profiling, anti-hyperglycemic, antifungal, and radicals scavenging potential of crude extracts of Athyrium asplenioides- an in-vitro approach

This research was aimed to evaluate the phytochemical profile, antifungal, anti-hyperglycemic, as well as antioxidant activity competence of different extracts of Athyrium asplenioides through in-vitro approach. The A. asplenioides crude methanol extract contained considerable quantity of pharmaceutically precious phytochemicals (saponins, tannins, quinones, flavonoid, phenols, steroid, and terpenoids) than others (acetone, ethyl acetate, and chloroform). Interestingly, the crude methanol extract showed remarkable antifungal activity against Candida species (C. krusei: 19.3 ± 2 mm > C. tropicalis: 18.4 ± 1 mm > C. albicans: 16.5 ± 1 mm > C. parapsilosis: 15.5 ± 2 mm  >  C. glabrate: 13.5 ± 2 mm > C. auris: 7.6 ± 1 mm) at a concentration of 20 mg mL-1. The crude methanol extract also showed remarkable anti-hyperglycemic activity on concentration basis. Surprisingly, remarkable free radicals scavenging potential against DPPH (76.38%) and ABTS (76.28%) free radicals at a concentration of 20 mg mL-1. According to the findings, the A. asplenioides crude methanol extract contains pharmaceutically valuable phytochemicals and may be useful for drug discovery.

Multi-drug resistant ESKAPE pathogens and the uses of plants as their antimicrobial agents

Infections by ESKAPE (Enterococcus sp., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) pathogens cause major concern due to their multi-drug resistance (MDR). The ESKAPE pathogens are frequently linked to greater mortality, diseases, and economic burden in healthcare worldwide. Therefore, the use of plants as a natural source of antimicrobial agents provide a solution as they are easily available and safe to use. These natural drugs can also be enhanced by incorporating silver nanoparticles and combining them with existing antibiotics. By focussing the attention on the ESKAPE organisms, the MDR issue can be addressed much better.

Plants as Biofactories for Therapeutic Proteins and Antiviral Compounds to Combat COVID-19

The outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) had a profound impact on the world's health and economy. Although the end of the pandemic may come in 2023, it is generally believed that the virus will not be completely eradicated. Most likely, the disease will become an endemicity. The rapid development of vaccines of different types (mRNA, subunit protein, inactivated virus, etc.) and some other antiviral drugs (Remdesivir, Olumiant, Paxlovid, etc.) has provided effectiveness in reducing COVID-19's impact worldwide. However, the circulating SARS-CoV-2 virus has been constantly mutating with the emergence of multiple variants, which makes control of COVID-19 difficult. There is still a pressing need for developing more effective antiviral drugs to fight against the disease. Plants have provided a promising production platform for both bioactive chemical compounds (small molecules) and recombinant therapeutics (big molecules). Plants naturally produce a diverse range of bioactive compounds as secondary metabolites, such as alkaloids, terpenoids/terpenes and polyphenols, which are a rich source of countless antiviral compounds. Plants can also be genetically engineered to produce valuable recombinant therapeutics. This molecular farming in plants has an unprecedented opportunity for developing vaccines, antibodies, and other biologics for pandemic diseases because of its potential advantages, such as low cost, safety, and high production volume. This review summarizes the latest advancements in plant-derived drugs used to combat COVID-19 and discusses the prospects and challenges of the plant-based production platform for antiviral agents.

Antiviral activities of plant-derived indole and β-carboline alkaloids against human and avian influenza viruses

The persistent evolution of drug-resistant influenza strains represents a global concern. The innovation of new treatment approaches through drug screening strategies and investigating the antiviral potential of bioactive natural-based chemicals may address the issue. Herein, we screened the anti-influenza efficacy of some biologically active indole and β-carboline (βC) indole alkaloids against two different influenza A viruses (IAV) with varied host range ranges; seasonal influenza A/Egypt/NRC098/2019(H1N1) and avian influenza A/chicken/Egypt/N12640A/2016(H5N1). All compounds were first assessed for their half-maximal cytotoxic concentration (CC₅₀) in MDCK cells and half-maximal inhibitory concentrations (IC₅₀) against influenza A/H5N1. Intriguingly, Strychnine sulfate, Harmalol, Harmane, and Harmaline showed robust anti-H5N1 activities with IC₅₀ values of 11.85, 0.02, 0.023, and 3.42 µg/ml, respectively, as compared to zanamivir and amantadine as control drugs (IC₅₀ = 0.079 µg/ml and 17.59 µg/ml, respectively). The efficacy of the predefined phytochemicals was further confirmed against influenza A/H1N1 and they displayed potent anti-H1N1 activities compared to reference drugs. Based on SI values, the highly promising compounds were then evaluated for antiviral efficacy through plaque reduction assay and consistently they revealed high viral inhibition percentages at non-toxic concentrations. By studying the modes of antiviral action, Harmane and Harmalol could suppress viral infection via interfering mainly with the viral replication of the influenza A/H5N1 virus, whilst Harmaline exhibited a viricidal effect against the influenza A/H5N1 virus. Whereas, Strychnine sulfate elucidated its anti-influenza potency by interfering with viral adsorption into MDCK cells. Consistently, chemoinformatic studies showed that all studied phytochemicals illustrated HB formations with essential peptide cleft through the NH of indole moiety. Among active alkaloids, harmalol displayed the best lipophilicity metrics including ligand efficiency (LE) and ligand lipophilic efficiency (LLE) for both viruses. Compounds geometry and their ability to participate in HB formation are very crucial.

Potential of glycyrrhizic and glycyrrhetinic acids against influenza type A and B viruses: A perspective to develop new anti-influenza compounds and drug delivery systems

Despite the recent dynamic development of medicine, influenza is still a significant epidemiological problem for people around the world. The growing resistance of influenza viruses to currently available antiviral drugs makes it necessary to search for new compounds or drug forms with potential high efficacy against human influenza A and B viruses. One of the methods of obtaining new active compounds is to chemically modify privileged structures occurring in the natural environment. The second solution, that is gaining more and more interest, is the use of modern drug carriers, which significantly improve physicochemical and pharmacokinetic parameters of the transported substances. Molecules known from the earliest times for their numerous therapeutic properties are glycyrrhizinic acid (GA) and glycyrrhetinic acid (GE). Both compounds constitute the main active agents of the licorice (Glycyrrhiza glabra, Leguminosae) root and, according to a number of scientific reports, show antiviral properties against both DNA and RNA viruses. The above information prompted many scientific teams around the world to obtain and test in vitro and/or in vivo new synthetic GA and GE derivatives against influenza A and B viruses. Similarly, in recent years, a significant amount of GA and GE-based drug delivery systems (DDS) such as nanoparticles, micelles, liposomes, nanocrystals, and carbon dots has been prepared and tested for antiviral activity, including those against influenza A and B viruses. This work systematizes the attempts undertaken to study the antiviral activity of new GA and GE analogs and modern DDS against clinically significant human influenza viruses, at the same time indicating the directions of their further development.

Chronobiological Efficacy of Combined Therapy of Pelargonium Sidoides and Melatonin in Acute and Persistent Cases of COVID-19: A Hypothetical Approach

Since the outbreak of the first SARS-CoV-2 epidemic in China, pharmacists have rapidly engaged and developed strategies for pharmaceutical care and supply. According to the guidelines of the International Pharmaceutical Federation (FIP), clinical pharmacists/hospital pharmacists, as members of care teams, play one of the most important roles in the pharmaceutical care of patients with COVID-19. During this pandemic, many immuno-enhancing adjuvant agents have become critical in addition to antivirals and vaccines in order to overcome the disease more easily. The liquid extract obtained from the Pelargonium sidoides plant is used for many indications such as colds, coughs, upper respiratory tract infections, sore throat, and acute bronchitis. The extract obtained from the roots of the plant has been observed to have antiviral and immunomodulatory activity. In addition to its anti-inflammatory and antioxidant effects, melatonin plays a role in suppressing the cytokine storm that can develop during COVID-19 infection. Knowing that the severity and duration of COVID-19 symptoms vary within 24 hours and/or in different time periods indicates that COVID-19 requires a chronotherapeutic approach. Our goal in the management of acute and long COVID is to synchronize the medication regimen with the patient's biological rhythm. This chapter provides a comprehensive review of the existing and emerging literature on the chronobiological use of Pelargonium sidoides and melatonin during acute and prolonged COVID-19 episodes.

Genome-wide analysis of AP2/ERF superfamily in Isatis indigotica

OBJECTIVE

AP2/ERF (APETALA2/ethylene-responsive factor) superfamily is one of the largest gene families in plants and has been reported to participate in various biological processes, such as the regulation of biosynthesis of active lignan. However, few studies have investigated the genome-wide role of the AP2/ERF superfamily in Isatis indigotica. This study establishes a complete picture of the AP2/ERF superfamily in I. indigotica and contributes valuable information for further functional characterization of IiAP2/ERF genes and supports further metabolic engineering.

METHODS

To identify the IiAP2/ERF superfamily genes, the AP2/ERF sequences from Arabidopsis thaliana and Brassica rapa were used as query sequences in the basic local alignment search tool. Bioinformatic analyses were conducted to investigate the protein structure, motif composition, chromosome location, phylogenetic relationship, and interaction network of the IiAP2/ERF superfamily genes. The accuracy of omics data was verified by quantitative polymerase chain reaction and heatmap analyses.

RESULTS

One hundred and twenty-six putative IiAP2/ERF genes in total were identified from the I. indigotica genome database in this study. By sequence alignment and phylogenetic analysis, the IiAP2/ERF genes were classified into 5 groups including AP2, ERF, DREB (dehydration-responsive element-binding factor), Soloist and RAV (related to abscisic acid insensitive 3/viviparous 1) subfamilies. Among which, 122 members were unevenly distributed across seven chromosomes. Sequence alignment showed that I. indigotica and A. thaliana had 30 pairs of orthologous genes, and we constructed their interaction network. The comprehensive analysis of gene expression pattern in different tissues suggested that these genes may play a significant role in organ growth and development of I. indigotica. Members that may regulate lignan biosynthesis in roots were also preliminarily identified. Ribonucleic acid sequencing analysis revealed that the expression of 76 IiAP2/ERF genes were up- or down-regulated under salt or drought treatment, among which, 33 IiAP2/ERF genes were regulated by both stresses.

CONCLUSION

This study undertook a genome-wide characterization of the AP2/ERF superfamily in I. indigotica, providing valuable information for further functional characterization of IiAP2/ERF genes and discovery of genetic targets for metabolic engineering.

Identification of novel potential inhibitors of varicella-zoster virus thymidine kinase from ethnopharmacologic relevant plants through an in-silico approach

Although Varicella or chickenpox infection which is caused by the varicella-zoster virus (VZV) has significantly been managed through vaccination, it remains an infection that poses threats to the nearest future due to therapeutic drawbacks. The focus of this research was geared towards in silico screening for the identification of novel compounds in plants of ethnopharmacological relevance in the treatment of chicken pox in West Africa. The work evaluated 65 compounds reported to be present in Achillea millefolium, Psidium guajava and Vitex doniana sweet to identify potential inhibitors of thymidine kinase, the primary drug target of varicella zoster virus. Out of the 65 compounds docked, 42 of these compounds were observed to possess binding energies lower than -7.0 kcal/mol, however only 20 were observed to form hydrogen bond interactions with the protein. These interactions were elucidated using LigPlot⁺ and MM-PBSA analysis with residue Ala134 predicted as critical for binding. Pharmacological profiling predicted three potential lead compounds comprising myricetin, apigenin- 4' -glucoside and Abyssinone V to possess good pharmacodynamics properties and negligibly toxic. The molecules were predicted as antivirals including anti-herpes and involved in mechanisms comprising inhibition of polymerase, ATPase and membrane integrity, which were corroborated previously in other viruses. These drug-like compounds are plausible biotherapeutic moieties for further biochemical and cell-based assaying to discover their potential for use against chickenpox. Communicated by Ramaswamy H. Sarma.

Bioactivity and In Silico Studies of Isoquinoline and Related Alkaloids as Promising Antiviral Agents: An Insight

Viruses are widely recognized as the primary cause of infectious diseases around the world. The ongoing global pandemic due to the emergence of SARS-CoV-2 further added fuel to the fire. The development of therapeutics becomes very difficult as viruses can mutate their genome to become more complex and resistant. Medicinal plants and phytocompounds could be alternative options. Isoquinoline and their related alkaloids are naturally occurring compounds that interfere with multiple pathways including nuclear factor-κB, mitogen-activated protein kinase/extracellular-signal-regulated kinase, and inhibition of Ca²⁺-mediated fusion. These pathways play a crucial role in viral replication. Thus, the major goal of this study is to comprehend the function of various isoquinoline and related alkaloids in viral infections by examining their potential mechanisms of action, structure-activity relationships (SAR), in silico (particularly for SARS-CoV-2), in vitro and in vivo studies. The current advancements in isoquinoline and related alkaloids as discussed in the present review could facilitate an in-depth understanding of their role in the drug discovery process.

Anti-Mayaro virus activity of a hydroethanolic extract from Fridericia chica (Bonpl.) L. G. Lohmann leaves

ETHNOPHARMACOLOGICAL RELEVANCE

Mayaro fever is a neglected tropical disease. The region of the most significant circulation of the Mayaro virus (MAYV) is the Amazon rainforest, situated in remote areas that are difficult to access and where medicine is scarce. Thus, the regional population uses plants as an alternative for the treatment of various diseases. Fridericia chica is an endemic plant of tropical regions used in traditional medicine to treat fever, malaise, inflammation, and infectious diseases such as hepatitis B. However, its antiviral activity is poorly understood.

AIM OF THE STUDY

This study aimed to investigate the anti-MAYV activity of the hydroethanolic extract of the leaves of Fridericia chica (HEFc) in mammalian cells and its possible mechanism of action.

MATERIALS AND METHODS

The antiviral activity of HEFc was studied using Vero cell lines against MAYV. The cytotoxicity and antiviral activity of the extract were evaluated by the 3-(4, 5- dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) assay. The overall antiviral activity was confirmed by the plaque forming units (PFU) method. Then, the effects of HEFc on MAYV multiplication kinetics, virus adsorption, penetration, and post-penetration, and its virucidal activity were determined in Vero cells using standard experimental procedures.

RESULTS

HEFc exerted a effect against viral infection in Vero cells at a non-cytotoxic concentration, and no virion was detected in the supernatant in a dose-dependent and selective manner. HEFc inhibited MAYV in the early and late stages of the viral multiplication cycle. The extract showed significant virucidal activity at low concentrations and did not affect adsorption or viral internalization stages. In addition, HEFc reduced virions at all post-infection times investigated.

CONCLUSIONS

HEFc has good antiviral activity against MAYV, acting directly on the viral particles. This plant extract possesses an excellent and promising potential for developing effective herbal antiviral drugs.

Role of ethno-phytomedicine knowledge in healthcare of COVID-19: advances in traditional phytomedicine perspective

Background

Since the outbreak of the COVID-19 virus, ethnomedicinal plants have been used in diverse geographical locations for their purported prophylactic and pharmacological effects. Medicinal plants have been relied on by people around the globe for centuries, as 80% of the world’s population rely on herbal medicines for some aspect of their primary health care needs, according to the World Health Organization.

Main body

This review portrays advances in traditional phytomedicine by bridging the knowledge of ethno-phytomedicine and COVID-19 healthcare. Ethnomedicinal plants have been used for symptoms related to COVID-19 as antiviral, anti-infective, anti-inflammatory, anti-oxidant, antipyretic, and lung–gut immune boosters. Traditionally used medicinal plants have the ability to inhibit virus entry and viral assembly, bind to spike proteins, membrane proteins, and block viral replications and enzymes. The efficacy of traditional medicinal plants in the terms of COVID-19 management can be evaluated by in vitro, in vivo as well as different in silico techniques (molecular docking, molecular dynamics simulations, machine learning, etc.) which have been applied extensively to the quest and design of effective biotherapeutics rapidly. Other advances in traditional phytomedicines against COVID-19 are controlled clinical trials, and notably the roles in the gut microbiome. Targeting the gut microbiome via medicinal plants as prebiotics is also found to be an alternative and potential strategy in the search for a COVID-19 combat strategy.

Conclusions

Since medicinal plants are the sources of modern biotherapeutics development, it is essential to build collaborations among ethnobotanists, scientists, and technologists toward developing the most efficient and the safest adjuvant therapeutics against the pandemic of the twenty-first century, COVID-19.

Plant Molecular Pharming and Plant-Derived Compounds towards Generation of Vaccines and Therapeutics against Coronaviruses

The current century has witnessed infections of pandemic proportions caused by Coronaviruses (CoV) including severe acute respiratory syndrome-related CoV (SARS-CoV), Middle East respiratory syndrome-related CoV (MERS-CoV) and the recently identified SARS-CoV2. Significantly, the SARS-CoV2 outbreak, declared a pandemic in early 2020, has wreaked devastation and imposed intense pressure on medical establishments world-wide in a short time period by spreading at a rapid pace, resulting in high morbidity and mortality. Therefore, there is a compelling need to combat and contain the CoV infections. The current review addresses the unique features of the molecular virology of major Coronaviruses that may be tractable towards antiviral targeting and design of novel preventative and therapeutic intervention strategies. Plant-derived vaccines, in particular oral vaccines, afford safer, effectual and low-cost avenues to develop antivirals and fast response vaccines, requiring minimal infrastructure and trained personnel for vaccine administration in developing countries. This review article discusses recent developments in the generation of plant-based vaccines, therapeutic/drug molecules, monoclonal antibodies and phytochemicals to preclude and combat infections caused by SARS-CoV, MERS-CoV and SARS-CoV-2 viruses. Efficacious plant-derived antivirals could contribute significantly to combating emerging and re-emerging pathogenic CoV infections and help stem the tide of any future pandemics.

Phytochemical profiling of antimicrobial and potential antioxidant plant: Nepeta cataria

Traditional and phytochemical studies have confirmed the richness and diversity of medicinal plants such as Nepeta cataria (N. cataria), but more studies are needed to complete its metabolite profiling. The objective of this research was to enhance the metabolomic picture and bioactivity of N. cataria for better evaluation. Phytochemical analysis was performed by bio-guided protocols and gas chromatography-mass spectrometry (GC/MS). For this, solvents such as methanol, ethanol, water, acetone, and hexane were used to extract a wide number of chemicals. Antibacterial analysis was performed using the 96-well plate test, Kirby Bauer's disk diffusion method, and the resazurin microdilution test. Antioxidant activity was determined by the DPPH assay and radical scavenging capacity was evaluated by the oxygen radical absorbance capacity (ORAC) assay. GC/MS analysis revealed a total of 247 identified and 127 novel metabolites from all extracts of N. cataria. Water and acetone extracts had the highest identified metabolites (n = 79), whereas methanol extract was the highest in unidentified metabolites (n = 48). The most abundant phytochemicals in methanol extract were 1-isopropylcyclohex-1-ene (concentration = 27.376) and bicyclo [2.2.1] heptan-2-one (concentration = 20.437), whereas in ethanol extract, it was 9,12,15-octadecatrienoic acid (concentration = 27.308) and 1-isopropylcyclohex-1-ene (concentration = 25.854). An abundance of 2 methyl indoles, conhydrin, and coumarin was found in water extracts; a good concentration of eucalyptol was found in acetone extract; and 7,9-di-tert-butyl-1-oxaspiro is the most abundant phytochemicals in hexane extracts. The highest concentration of flavonoids and phenols were identified in hexane and methanol extracts, respectively. The highest antioxidant potential (DPPH assay) was observed in acetone extract. The ethanolic extract exhibited a two-fold higher ORAC than the methanol extract. This examination demonstrated the inhibitory effect against a set of microbes and the presence of polar and non-polar constituents of N. cataria. The results of this study provide a safe resource for the development of food, agriculture, pharmaceutical, and other industrial products upon further research validation.

Garcinia cambogia Phenolics as Potent Anti-COVID-19 Agents: Phytochemical Profiling, Biological Activities, and Molecular Docking

COVID-19 is a disease caused by the coronavirus SARS-CoV-2 and became a pandemic in a critically short time. Phenolic secondary metabolites attracted much attention from the pharmaceutical industries for their easily accessible natural sources and proven antiviral activity. In our mission, a metabolomics study of the Garcinia cambogia Roxb. fruit rind was performed using LC-HRESIMS to investigate its chemical profile, especially the polar aspects, followed by a detailed phytochemical analysis, which led to the isolation of eight known compounds. Using spectrometric techniques, the isolated compounds were identified as quercetin, amentoflavone, vitexin, rutin, naringin, catechin, p-coumaric, and gallic acids. The antiviral activities of the isolated compounds were investigated using two assays; the 3CL-M^pro enzyme showed that naringin had a potent effect with IC₅₀ 16.62 μg/mL, followed by catechin and gallic acid (IC₅₀ 26.2, 30.35 μg/mL, respectively), while the direct antiviral inhibition effect of naringin confirmed the potency with an EC₅₀ of 0.0169 μM. To show the molecular interaction, in situ molecular docking was carried out using a COVID-19 protease enzyme. Both biological effects and docking studies showed the hydrophobic interactions with Gln 189 or Glu 166, per the predicated binding pose of the isolated naringin.

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 21^st 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.

Phenolic compounds versus SARS-CoV-2: An update on the main findings against COVID-19

The COVID-19 pandemic caused by SARS-CoV-2 remains an international concern. Although there are drugs to fight it, new natural alternatives such as polyphenols are essential due to their antioxidant activity and high antiviral potential. In this context, this review reports the main findings on the effect of phenolic compounds (PCs) against SARS-CoV-2 virus. First, the proven activity of PCs against different human viruses is briefly detailed, which serves as a starting point to study their anti-COVID-19 potential. SARS-CoV-2 targets (its proteins) are defined. Findings from in silico, in vitro and in vivo studies of a wide variety of phenolic compounds are shown, emphasizing their mechanism of action, which is fundamental for drug design. Furthermore, clinical trials have demonstrated the effectiveness of PCs in the prevention and as a possible therapeutic management against COVID-19. The results were complemented with information on the influence of polyphenols in strengthening/modulating the immune system. It is recommended to investigate compounds such as vitamins, minerals, alkaloids, triterpenes and fatty acids, and their synergistic use with PCs, many of which have been successful against SARS-CoV-2. Based on findings on other viruses, synergistic evaluation of PCs with accepted drugs against COVID-19 is also suggested. Other recommendations and limitations are also shown, which is useful for professionals involved in the development of efficient, safe and low-cost therapeutic strategies based on plant matrices rich in PCs. To the authors' knowledge, this manuscript is the first to evaluate the relationship between the antiviral and immunomodulatory (including anti-inflammatory and antioxidant effects) activity of PCs and their underlying mechanisms in relation to the fight against COVID-19. It is also of interest for the general population to be informed about the importance of consuming foods rich in bioactive compounds for their health benefits.

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Phenolic compounds are known for their high potential against various human viruses.

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Phenolic compounds also have anti-inflammatory and immunomodulatory activity.

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Medicinal plants used against COVID-19 are rich in phenolic compounds.

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Phenolic compounds interfere with the activity of SARS-CoV-2 proteins.

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A wide variety of food products with high polyphenolic content are presented.

Ethnomedical, phytochemical and pharmacological insights on an Indian medicinal plant: The balloon vine (Cardiospermum halicacabum Linn.)

ETHNOPHARMACOLOGICAL RELEVANCE

Cardiospermum halicacabum Linn. (C. halicacabum) is one of the well-known leafy green vegetables in India. It is an herbaceous climber from the Sapindaceae family which is found in almost every Continent and Oceania. In the traditional Indian medicine systems, this plant is used for the treatment of rheumatism, abdominal pain, orchitis, dropsy, lumbago, skin diseases, cough, nervous disorders, and hyperthermia.

AIM OF THE REVIEW

This review presents the current information about ethnomedical uses and progress on geographical distribution, pharmacological activities, phytochemistry, micropropagation, and toxicity of C. halicacabum. Also, critically summarizes the relationship between the reported pharmacological activities and the traditional usages along with the future perspectives for research on this medicinal plant.

MATERIALS AND METHODS

The data on C. halicacabum were collected using multiple internet sources such as Google Scholar, Science Direct, Taylor & Francis, PubMed, Web of Science, Springer Link, Wiley online, and plant databases.

RESULTS

Chemical characterization using LC-MS/MS, HPLC, and NMR exposed the presence of chlorogenic acid, caffeic acid, coumaric acid, luteolin-7-o-glucuronide, apigenin-7-o-glucuronide, and chrysoeriol in different parts of C. halicacabum. Based on the outcomes of this review, the main bioactive compounds found in C. halicacabum include phenols, phenolic acids, flavonoids, flavonoid glycosides, and flavonoid glucuronides. Besides the above-mentioned constituents, palmitic acid, oleic acid, stearic acid, linolenic acid, eicosenoic acid, and arachidic acid are the compounds that constitute the fatty acid profile of C. halicacabum seeds. Specifically, Cardiospermin, a bioactive compound isolated from the root extract of C. halicacabum has been recognized for its anxiolytic activity. Moreover, C. halicacabum showed a broad spectrum of pharmacological activities including anti-inflammatory, anti-arthritic, anti-diabetic, anxiolytic activity, antiulcer, apoptotic activity, antibacterial, antiviral, anti-diarrheal, antioxidant, hepatoprotective, and nephroprotective properties. However, the bioactive compounds responsible for most of the above therapeutic properties have not been elucidated till now.

CONCLUSION

Phytochemicals from C. halicacabum showed noticeable pharmacological effects against plethora of health disorders. Some of the traditional applications were supported by modern scientific studies, however, more pharmacological evaluations should be conducted to validate other traditional uses of C. halicacabum. Despite C. halicacabum's vast pharmacological activity, additional human clinical trials are needed to determine the potent and safe dosages for the treatment of various health abnormalities. Besides, bioassay-guided isolation of active constituents, pharmacokinetic evaluations and identification of their mode of action are recommended for future investigations on C. halicacabum to unveil its therapeutic drug leads. Overall, this review suggests that C. halicacabum could be a new source of functional foods.

Medicinal Herbs in the Relief of Neurological, Cardiovascular, and Respiratory Symptoms after COVID-19 Infection A Literature Review

COVID-19 infection causes complications, even in people who have had a mild course of the disease. The most dangerous seem to be neurological ailments: anxiety, depression, mixed anxiety–depressive (MAD) syndromes, and irreversible dementia. These conditions can negatively affect the respiratory system, circulatory system, and heart functioning. We believe that phytotherapy can be helpful in all of these conditions. Clinical trials confirm this possibility. The work presents plant materials (Valeriana officinalis, Melissa officinalis, Passiflora incarnata, Piper methysticum, Humulus lupulus, Ballota nigra, Hypericum perforatum, Rhodiola rosea, Lavandula officinalis, Paullinia cupana, Ginkgo biloba, Murraya koenigii, Crataegus monogyna and oxyacantha, Hedera helix, Polygala senega, Pelargonium sidoides, Lichen islandicus, Plantago lanceolata) and their dominant compounds (valeranon, valtrate, apigenin, citronellal, isovitexin, isoorientin, methysticin, humulone, farnesene, acteoside, hypericin, hyperforin, biapigenin, rosavidin, salidroside, linalool acetate, linalool, caffeine, ginkgolide, bilobalide, mihanimbine, epicatechin, hederacoside C,α-hederine, presegenin, umckalin, 6,7,8-trixydroxybenzopyranone disulfate, fumaroprotocetric acid, protolichesteric acid, aucubin, acteoside) responsible for their activity. It also shows the possibility of reducing post-COVID-19 neurological, respiratory, and cardiovascular complications, which can affect the functioning of the nervous system.

Bioactive Components of Houttuynia cordata Thunb and Their Potential Mechanisms Against COVID-19 Using Network Pharmacology and Molecular Docking Approaches

We investigated the molecular mechanism by which Houttuynia cordata Thunb (HCT) may intervene in coronavirus disease 2019 (COVID-19) and COVID-19-induced cytokine storms using network pharmacology and molecular docking approaches. Using the Traditional Chinese medicine Systems Pharmacology Database and Analysis Platform (TCMSP), a "component-target-pathway" topology map of HCT for COVID-19 treatment was constructed using Cytoscape. Core target genes were analyzed using the STRING database, and the signal pathway map and biological mechanism of COVID-19 therapy were obtained using cluster profilers. Active components of HCT were docked with severe respiratory syndrome coronavirus 2 (SARS-CoV-2) 3C-like protease (3CL^pro) and RNA-dependent RNA polymerase (RdRp) using AutoDockTools. Data visualization and statistical analysis were conducted using the R program. A molecular dynamic simulation was carried out with the Groningen Machine for Chemical Simulation program. HCT had six active anti-COVID-19 ingredients and 45 molecular targets. Their crucial target proteins for COVID-19 treatment were the RELA (nuclear factor kappa B [NF-κB] p65 subunit), interleukin 6, and mitogen-activated protein kinase 1. In functional enrichment analysis, the potential molecular targets of active components of HCT for COVID-19 treatment belonged to 18 signaling pathways (adjusted P = 2.12E-11). Gene ontology obtained by Kyoto Encyclopedia of Genes and Genome enrichment screening showed that the primary mechanism of COVID-19 treatment was upregulation of protein kinase C followed by downregulations of T cell differentiation and proliferation and NF-κB signaling. Molecular docking showed that the active components of HCT (quercetin and kaempferol) had similar binding affinities for SARS-CoV-2 3CL^pro and SARS-CoV-2 RdRp, primary COVID-19 target proteins as did clinically used drugs. These results were confirmed with molecular dynamics simulation. In conclusion, multiple components of HCT, especially quercetin and kaempferol, have the potential to treat COVID-19 infection and COVID-19-induced cytokine storm by targeting multiple proteins.

Pharmacophore based virtual screening for natural product database revealed possible inhibitors for SARS-COV-2 main protease

The challenge continues globally triggered by the absence of an approved antiviral drug against COVID-19 virus infection necessitating global concerted efforts of scientists. Nature still provides a renewable source for drugs used to solve many health problems. The aim of this work is to provide new candidates from natural origin to overcome COVID-19 pandemic. A virtual screening of the natural compounds database (47,645 compounds) using structure-based pharmacophore model and molecular docking simulations reported eight hits from natural origin against SARS-CoV-2 main proteinase (Mpro) enzyme. The successful candidates were of terpenoidal nature including taxusabietane, Isoadenolin A & C, Xerophilusin B, Excisanin H, Macrocalin B and ponicidin, phytoconstituents isolated from family Lamiaceae and sharing a common ent-kaurane nucleus, were found to be the most successful candidates. This study suggested that the diterpene nucleus has a clear positive contribution which can represent a new opportunity in the development of SARS-CoV-2 main protease inhibitors.

Revisiting liquorice (Glycyrrhiza glabra L.) as anti-inflammatory, antivirals and immunomodulators: Potential pharmacological applications with mechanistic insight

BACKGROUND

Glycyrrhiza glabra L. (G. glabra) commonly known as liquorice is one of the highly exploited and utilized medicinal plant of the world. Since ancient times liquorice is considered as an auspicious and valuable traditional medicine across the world for treatment of various ailments.

METHOD

Several electronic online scientific databases such as Science Direct, PubMed, Scopus, Scifinder, Google Scholar, online books and reports were assessed for collecting information. All the collected information was classified into different sections to meet the objective of the paper.

RESULTS

The electronic database search yielded 3908 articles from different countries. Out of them one ninety-eight articles published between 1956 and 2021 were included, corresponding to all detailed review on G. glabra and research on anti-inflammatories, antivirals and immunomodulatory through pre-clinical and clinical models. From all selective area of studies on G. glabra and its bioactive components it was established (including molecular mechanisms) as a suitable remedy as per the current requirement of pandemic situation arise through respiratory tract infection.

CONCLUSION

Different relevant studies have been thoroughly reviewed to gain an insight on utility of liquorice and its bioactive constituents for anti-inflammatories, antivirals and immunomodulatory effects with special emphasized for prevention and treatment of COVID-19 infection with possible mechanism of action at molecular level. Proposed directions for future research are also outlined to encourage researchers to find out various mechanistic targets and useful value added products of liquorice in future investigations.

Potential Inhibitors Identification of Severe Acute Respiratory Syndrome-Related Coronavirus 2 (SARS-CoV-2) Angiotensin-Converting Enzyme 2 and Main Protease from Anatolian Traditional Plants

Background:

The 2019 novel coronavirus disease (COVID-19) has caused a global health catastrophe by affecting the whole human population around the globe. Unfortunately, there is no specific medication or treatment for COVID-19 currently available.

Objective:

It’s extremely necessary to apply effective drug treatment in order to end the pandemic period and return daily life to normal. In terms of the urgency of treatment, rather than focusing on the discovery of novel compounds, it is critical to explore the effects of existing herbal agents with proven antiviral properties on the virus.

Method:

Molecular docking studies were carried out with three different methods, Glide extra precision (XP) docking, Induced Fit docking (IFD), and Molecular Mechanics/Generalized Born Surface Area (MM/GBSA), to determine the potential effects of 58 phytochemicals in the content of Rosmarinus officinalis, Thymbra spicata, Satureja thymbra, and Stachys lavandulifolia plants -have antiviral and antibacterial effects- against Main Protease (Mpro) and Angiotensin Converting Enzyme 2 (ACE2) enzymes.

Results:

7 compounds stand out among all molecules by showing very high binding affinities. According to our findings, the substances chlorogenic acid, rosmarinic acid, and rosmanol exhibit extremely significant binding affinities for both Mpro and ACE2 enzymes. Furthermore, it was discovered that carnosic acid and alpha-cadinol showed potential anti-Mpro activity, whereas caffeic acid and carvacrol had promising anti-ACE2 activity.

Conclusion:

Chlorogenic acid, rosmarinic acid, rosmanol, carnosic acid, alpha-cadinol, caffeic acid, and carvacrol compounds have been shown to be powerful anti-SARS-COV-2 agents in docking simulations against Mpro and ACE2 enzymes, as well as ADME investigations.

Jeopardy of COVID-19: Rechecking the Perks of Phytotherapeutic Interventions

The novel coronavirus disease (COVID-19), the reason for worldwide pandemic, has already masked around 220 countries globally. This disease is induced by Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2). Arising environmental stress, increase in the oxidative stress level, weak immunity and lack of nutrition deteriorates the clinical status of the infected patients. Though several researches are at its peak for understanding and bringing forward effective therapeutics, yet there is no promising solution treating this disease directly. Medicinal plants and their active metabolites have always been promising in treating many clinical complications since time immemorial. Mother nature provides vivid chemical structures, which act multi-dimensionally all alone or synergistically in mitigating several diseases. Their unique antioxidant and anti-inflammatory activity with least side effects have made them more effective candidate for pharmacological studies. These medicinal plants inhibit attachment, encapsulation and replication of COVID-19 viruses by targeting various signaling molecules such as angiotensin converting enzyme-2, transmembrane serine protease 2, spike glycoprotein, main protease etc. This property is re-examined and its potency is now used to improve the existing global health crisis. This review is an attempt to focus various antiviral activities of various noteworthy medicinal plants. Moreover, its implications as prophylactic or preventive in various secondary complications including neurological, cardiovascular, acute kidney disease, liver disease are also pinpointed in the present review. This knowledge will help emphasis on the therapeutic developments for this novel coronavirus where it can be used as alone or in combination with the repositioned drugs to combat COVID-19.

Nanotechnology Applications of Flavonoids for Viral Diseases

Recent years have witnessed the emergence of several viral diseases, including various zoonotic diseases such as the current pandemic caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Other viruses, which possess pandemic-causing potential include avian flu, Ebola, dengue, Zika, and Nipah virus, as well as the re-emergence of SARS (Severe Acute Respiratory Syndrome) and MERS (Middle East Respiratory Syndrome) coronaviruses. Notably, effective drugs or vaccines against these viruses are still to be discovered. All the newly approved vaccines against the SARS-CoV-2-induced disease COVID-19 possess real-time possibility of becoming obsolete because of the development of ‘variants of concern’. Flavonoids are being increasingly recognized as prophylactic and therapeutic agents against emerging and old viral diseases. Around 10,000 natural flavonoid compounds have been identified, being phytochemicals, all plant-based. Flavonoids have been reported to have lesser side effects than conventional anti-viral agents and are effective against more viral diseases than currently used anti-virals. Despite their abundance in plants, which are a part of human diet, flavonoids have the problem of low bioavailability. Various attempts are in progress to increase the bioavailability of flavonoids, one of the promising fields being nanotechnology. This review is a narrative of some anti-viral dietary flavonoids, their bioavailability, and various means with an emphasis on the nanotechnology system(s) being experimented with to deliver anti-viral flavonoids, whose systems show potential in the efficient delivery of flavonoids, resulting in increased bioavailability.

Egypt's COVID-19 Recent Happenings and Perspectives: A Mini-Review

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has affected countries across the world. While the zoonotic aspects of SARS-CoV-2 are still under investigation, bats and pangolins are currently cited as the animal origin of the virus. Several types of vaccines against COVID-19 have been developed and are being used in vaccination drives across the world. A number of countries are experiencing second and third waves of the pandemic, which have claimed nearly four million lives out of the 180 million people infected globally as of June 2021. The emerging SARS-CoV-2 variants and mutants are posing high public health concerns owing to their rapid transmissibility, higher severity, and in some cases, ability to infect vaccinated people (vaccine breakthrough). Here in this mini-review, we specifically looked at the efforts and actions of the Egyptian government to slow down and control the spread of COVID-19. We also review the COVID-19 statistics in Egypt and the possible reasons behind the low prevalence and high case fatality rate (CFR%), comparing Egypt COVID-19 statistics with China (the epicenter of COVID-19 pandemic) and the USA, Brazil, India, Italy, and France (the first countries in which the numbers of patients infected with COVID-19). Additionally, we have summarized the SARS-CoV-2 variants, vaccines used in Egypt, and the use of medicinal plants as preventive and curative options.

Possible Use of Phytochemicals for Recovery from COVID-19-Induced Anosmia and Ageusia

The year 2020 became the year of the outbreak of coronavirus, SARS-CoV-2, which escalated into a worldwide pandemic and continued into 2021. One of the unique symptoms of the SARS-CoV-2 disease, COVID-19, is the loss of chemical senses, i.e., smell and taste. Smell training is one of the methods used in facilitating recovery of the olfactory sense, and it uses essential oils of lemon, rose, clove, and eucalyptus. These essential oils were not selected based on their chemical constituents. Although scientific studies have shown that they improve recovery, there may be better combinations for facilitating recovery. Many phytochemicals have bioactive properties with anti-inflammatory and anti-viral effects. In this review, we describe the chemical compounds with anti- inflammatory and anti-viral effects, and we list the plants that contain these chemical compounds. We expand the review from terpenes to the less volatile flavonoids in order to propose a combination of essential oils and diets that can be used to develop a new taste training method, as there has been no taste training so far. Finally, we discuss the possible use of these in clinical settings.

Luteolin and hormesis

The present paper provides the first integrated assessment of the capacity of luteolin to induce hormetic dose responses. It was shown that luteolin induced hormetic responses in multiple biological systems, including enhancing neuroprotection in various experimental model disease systems, improving wounding healing, especially in experimental models of high-risk population subgroups, such as diabetics, as well as enhancing osteogenesis in models of osteoporosis. The mechanistic basis for the luteolin-induced hormetic dose responses has been demonstrated to commonly involve the upregulation of the nuclear factor erythroid-derived 2-like 2 (Nrf2), which mediates the extensive range of anti-inflammatory effects induced by luteolin in multiple cell types and organ systems.

Mechanistic Aspects of Medicinal Plants and Secondary Metabolites against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)

BACKGROUND AND OBJECTIVE

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), a highly pathogenic virus, is responsible for a respiratory disease termed coronavirus disease 2019 (COVID-19). SARS-CoV-2 genome encodes various structural and non-structural proteins, which are necessary for viral entry and replication. Among these proteins, papain-like protease (PLpro), 3C-like protease (3CLpro), RNA-dependent RNA polymerase (RdRp), helicase, a serine protease, and spike protein are potential targets of herbal remedies and phytocompounds for inhibition of viral infection and replication. There is at present no confirmed cure for the COVID-19. Various plants and their components have been introduced against SARS-Co-2. A number of review articles have also been published on them. This article is focusing on the mechanistic aspects of these plants and their derivatives on SARS-CV-2.

METHOD

The material in this review article was prepared from significant scientific databases, including Web of Science, PubMed, Science Direct, Scopus and Google Scholar.

RESULTS

Different medicinal plants and their phytocompounds interact with important structural and non-structural of SARS-CoV-2 proteins. Natural compounds form strong bonds with the active site of SARS-CoV-2 protease and make large conformational changes. These phytochemicals are potential inhibitors of structural and non-structural of SARS-CoV-2 proteins such as Spike protein, PLpro, and 3CLpro. Some important anti-SARS-CoV-2 actions of medicinal plants and their metabolites are inhibition of the virus replication or entry, blocking the angiotensin-converting enzyme 2 (ACE-2) receptor and "Transmembrane protease, serine 2 (TMPRSS2)" regulation of inflammatory mediators, inhibition of endothelial activation, toll-like receptors (TLRs) and activation of the nuclear factor erythroid-derived 2-related factor 2 (Nrf2). Some of these important natural immune boosters that are helpful for prevention and curing various symptoms related to COVID-19 include Allium sativum, Nigella sativa, Glycyrrhiza glabra Zingiber officinalis, Ocimum sanctum, Withania somnifera, Tinospora cordifolia, and Scutellaria baicalensis. Also, Kaempferol, Quercetin, Baicalin, Scutellarin, Glycyrrhizin, Curcumin, Apigenin, Ursolic acid, and Chloroquine are the best candidates for treating the symptoms associated with SARS-CoV-2 infection.

CONCLUSION

Medicinal plants and/or their bioactive compounds with inhibitory effects against SARS-CoV-2 support the human immune system and help in fighting against COVID-19 and rejuvenating the immune system.

Iron-doped zinc oxide nanoparticles-triggered elicitation of important phenolic compounds in cell cultures of Fagonia indica

The callus cultures of Fagonia indica could prove as factories for the production of important phytochemicals when triggered through different types of stress. In this study, we initiated callus cultures from healthy stem explants in the presence of iron-doped zinc oxide nanoparticles (Fe-ZnO-NPs). We performed experiments with the callus cultures of F. indica to determine the impact of Fe-ZnO-NPs in concentrations (15.62-250 µg/mL) on biomass accumulation, production of important phenolic and flavonoids, and antioxidative potential. Our results showed that maximum callus biomass [Fresh weight (FW) = 13.6 g and Dry weight (DW) = 0.58 ± 0.01] was produced on day 40 when the media was supplemented with 250 μg/mL Fe-ZnO-NPs. Similarly, maximum total phenolic content (268.36 μg GAE/g of DW) was observed in 40 days old callus added with 125 μg/mL Fe-ZnO-NPs. Maximum total flavonoid content (78.56 μg QE/g of DW) was recorded in 20 days old callus grown in 62.5 μg/mL Fe-ZnO-NPs containing media. Maximum total antioxidant capacity (390.74 µg AAE/g of DW) was recorded in 40 days old callus with 125 μg/mL Fe-ZnO-NPs treated cultures, respectively. Similarly, the highest free radical scavenging activity (93.02%) was observed in callus derived from media having 15.62 µg/mL Fe-ZnO-NPs. The antioxidant potential was observed to have positive correlation with TPC (r = 0.44). HPLC analysis showed that Fe-ZnO-NPs produced compounds (e.g., Epigallocatechin gallate) that were either absent or in lesser quantities in the control group. These results showed that Fe-ZnO-NPs elicitors could increase the biomass and activate secondary metabolism in F. indica cells.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11240-021-02123-1.

Phenolic compounds as promising drug candidates against COVID-19 - An integrated molecular docking and dynamics simulation study

Piper was used to cure certain human afflictions. It has various biological processes in literary works. Our work aims to identify and to explain the molecular base in silico in phytoderived anti-viral compounds in Piper nigrum against the major protease enzyme COVID-19. The thesis includes docking and molecular dynamic modelling review of 8 phenolic compounds from Piper extracted from the PubMed database. Docking analysis with Autodock programme was conducted. Our analysis reveals that the two Piper phytochemicals are very susceptible to the COVID-19 major protease enzyme. These phyto-compounds from piper may use contemporary techniques to create a stable drug or help the detection of lead. In order to assess their efficacy against COVID-19, identified hit compounds can be taken further in vitro and in vivo tests.

Andrographis paniculata (Burm. F.) Wall. Ex Nees, Andrographolide, and Andrographolide Analogues as SARS-CoV-2 Antivirals? A Rapid Review

Drug repurposing is commonly employed in the search for potential therapeutic agents. Andrographis paniculata, a medicinal plant commonly used for symptomatic relief of the common cold, and its phytoconstituent andrographolide, have been repeatedly identified as potential antivirals against SARS-CoV-2. In light of new evidence emerging since the onset of the COVID-19 pandemic, this rapid review was conducted to identify and evaluate the current SARS-CoV-2 antiviral evidence for A. paniculata, andrographolide, and andrographolide analogs. A systematic search and screen strategy of electronic databases and gray literature was undertaken to identify relevant primary articles. One target-based in vitro study reported the 3CLpro inhibitory activity of andrographolide as being no better than disulfiram. Another Vero cell-based study reported potential SARS-CoV-2 inhibitory activity for both andrographolide and A. paniculata extract. Eleven in silico studies predicted the binding of andrographolide and its analogs to several key antiviral targets of SARS-CoV-2 including the spike protein-ACE-2 receptor complex, spike protein, ACE-2 receptor, RdRp, 3CLpro, PLpro, and N-protein RNA-binding domain. In conclusion, in silico and in vitro studies collectively suggest multi-pathway targeting SARS-CoV-2 antiviral properties of andrographolide and its analogs, but in vivo data are needed to support these predictions.

An Updated Review of SARS-CoV-2 Vaccines and the Importance of Effective Vaccination Programs in Pandemic Times

Since the worldwide COVID-19 pandemic was declared a year ago, the search for vaccines has become the top priority in order to restore normalcy after 2.5 million deaths worldwide, overloaded sanitary systems, and a huge economic burden. Vaccine development has represented a step towards the desired herd immunity in a short period of time, owing to a high level of investment, the focus of researchers, and the urge for the authorization of the faster administration of vaccines. Nevertheless, this objective may only be achieved by pursuing effective strategies and policies in various countries worldwide. In the present review, some aspects involved in accomplishing a successful vaccination program are addressed, in addition to the importance of vaccination in a pandemic in the face of unwillingness, conspiracy theories, or a lack of information among the public. Moreover, we provide some updated points related to the landscape of the clinical development of vaccine candidates, specifically, the top five vaccines that are already being assessed in Phase IV clinical trials (BNT162b2, mRNA-1273, AZD1222, Ad26.COV2.S, and CoronaVac).

COVID-19 Prophylaxis Efforts Based on Natural Antiviral Plant Extracts and Their Compounds

During the time of the novel coronavirus disease 2019 (COVID-19) pandemic, it has been crucial to search for novel antiviral drugs from plants and well as other natural sources as alternatives for prophylaxis. This work reviews the antiviral potential of plant extracts, and the results of previous research for the treatment and prophylaxis of coronavirus disease and previous kinds of representative coronaviruses group. Detailed descriptions of medicinal herbs and crops based on their origin native area, plant parts used, and their antiviral potentials have been conducted. The possible role of plant-derived natural antiviral compounds for the development of plant-based drugs against coronavirus has been described. To identify useful scientific trends, VOSviewer visualization of presented scientific data analysis was used.