Broad-spectrum antiviral activity of chebulagic acid and punicalagin against viruses that use glycosaminoglycans for entry

Transcription factor EB (TFEB) interaction with RagC is disrupted during enterovirus D68 infection

Enterovirus D68 (EV-D68) is a picornavirus associated with severe respiratory illness and a paralytic disease called acute flaccid myelitis in infants. Currently, no protective vaccines or antivirals are available to combat this virus. Like other enteroviruses, EV-D68 uses components of the cellular autophagy pathway to rewire membranes for its replication. Here, we show that transcription factor EB (TFEB), the master transcriptional regulator of autophagy and lysosomal biogenesis, is crucial for EV-D68 infection. Knockdown of TFEB attenuated EV-D68 genomic RNA replication but did not impact viral binding or entry into host cells. The 3C protease of EV-D68 cleaves TFEB at the N-terminus at glutamine 60 (Q60) immediately post-peak viral RNA replication, disrupting TFEB-RagC interaction and restricting TFEB transport to the surface of the lysosome. Despite this, TFEB remained mostly cytosolic during EV-D68 infection. Overexpression of a TFEB mutant construct lacking the RagC-binding domain, but not the wild-type construct, blocks autophagy and increases EV-D68 nonlytic release in H1HeLa cells but not in autophagy-defective ATG7 KO H1HeLa cells. Our results identify TFEB as a vital host factor regulating multiple stages of the EV-D68 lifecycle and suggest that TFEB could be a promising target for antiviral development against EV-D68.

IMPORTANCE

Enteroviruses are among the most significant causes of human disease. Some enteroviruses are responsible for severe paralytic diseases such as poliomyelitis or acute flaccid myelitis. The latter disease is associated with multiple non-polio enterovirus species, including enterovirus D68 (EV-D68), enterovirus 71, and coxsackievirus B3 (CVB3). Here, we demonstrate that EV-D68 interacts with a host transcription factor, transcription factor EB (TFEB), to promote viral RNA(vRNA) replication and regulate the egress of virions from cells. TFEB was previously implicated in the viral egress of CVB3, and the viral protease 3C cleaves TFEB during infection. Here, we show that EV-D68 3C protease also cleaves TFEB after the peak of vRNA replication. This cleavage disrupts TFEB interaction with the host protein RagC, which changes the localization and regulation of TFEB. TFEB lacking a RagC-binding domain inhibits autophagic flux and promotes virus egress. These mechanistic insights highlight how common host factors affect closely related, medically important viruses differently.

In silico molecular study of hepatitis B virus X protein as a therapeutic target

The Hepatitis B virus is a leading cause of liver cirrhosis and hepatocellular carcinoma. HBx viral protein is considered a contributor to pathogenesis and hepatocarcinogenesis. This study aimed to screen the effect of some antiviral compounds to target HBx protein for inhibition of its function. Here, molecular docking, molcular dynsmic simulation, MM/GBSA and T-SNE methods were applied to study the complex stability and to cluster the conformations that generated in the simulation. Among the 179 compounds screened in this study, three antiviral agents (SC75741, Punicalagin, and Ledipasvir) exhibited the lowest docking energy and best interaction. Among these compounds, SC75741 was identified as a potent inhibitor of HBx that showed the best and most stable interaction during molecular dynamic simulation, and blocking a region near to HBx helix resides (aa 88-100) that is associated with cell invasion. The analysis of relative binding free energy through MM/GBSA for molecular dynamic simulation results revealed binding energy -9.9 kcal/mol for SC75741, -11 kcal/mol for Punicalagin, and -10.1 kcal/mol for Ledipasvir. These results elucidate the possible use of these compounds in the research for targeting HBx.Communicated by Ramaswamy H. Sarma.

Inhibition of NS2B-NS3 protease from all four serotypes of dengue virus by punicalagin, punicalin and ellagic acid identified from Punica granatum

Despite a major threat to the public health in tropical and subtropical regions, dengue virus (DENV) infections are untreatable. Therefore, efforts are needed to investigate cost-effective therapeutic agents that could cure DENV infections in future. The NS2B-NS3 protease encoded by the genome of DENV is considered a critical target for the development of anti-dengue drugs. The objective of the current study was to find out a specific inhibitor of the NS2B-NS3 proteases from all four serotypes of DENV. To begin with, nine plant extracts with a medicinal history were evaluated for their role in inhibiting the NS2B-NS3 proteases by Fluorescence Resonance Energy Transfer (FRET) assay. Among the tested extracts, Punica granatum was found to be the most effective one. The metabolic profiling of this extract revealed the presence of several active compounds, including ellagic acid, punicalin and punicalagin, which are well-established antiviral agents. Further evaluation of IC50 values of these three antiviral molecules revealed punicalagin as the most potent anti-NS2B-NS3 protease drug with IC50 of 0.91 ± 0.10, 0.75 ± 0.05, 0.42 ± 0.03, 1.80 ± 0.16 µM against proteases from serotypes 1, 2, 3 and 4, respectively. The docking studies demonstrated that these compounds interacted at the active site of the enzyme, mainly with His and Ser residues. Molecular dynamics simulations analysis also showed the structural stability of the NS2B-NS3 proteases in the presence of punicalagin. In summary, this study concludes that the punicalagin can act as an effective inhibitor against NS2B-NS3 proteases from all four serotypes of DENV.Communicated by Ramaswamy H. Sarma.

Pseudorabies virus upregulates low-density lipoprotein receptors to facilitate viral entry

Pseudorabies virus (PRV) is the causative agent of Aujeszky's disease in pigs. The low-density lipoprotein receptor (LDLR) is a transcriptional target of the sterol-regulatory element-binding proteins (SREBPs) and participates in the uptake of LDL-derived cholesterol. However, the involvement of LDLR in PRV infection has not been well characterized. We observed an increased expression level of LDLR mRNA in PRV-infected 3D4/21, PK-15, HeLa, RAW264.7, and L929 cells. The LDLR protein level was also upregulated by PRV infection in PK-15 cells and in murine lung and brain. The treatment of cells with the SREBP inhibitor, fatostatin, or with SREBP2-specific small interfering RNA prevented the PRV-induced upregulation of LDLR expression as well as viral protein expression and progeny virus production. This suggested that PRV activated SREBPs to induce LDLR expression. Furthermore, interference in LDLR expression affected PRV proliferation, while LDLR overexpression promoted it. This indicated that LDLR was involved in PRV infection. The study also demonstrated that LDLR participated in PRV invasions. The overexpression of LDLR or inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9), which binds to LDLR and targets it for lysosomal degradation, significantly enhanced PRV attachment and entry. Mechanistically, LDLR interacted with PRV on the plasma membrane, and pretreatment of cells with LDLR antibodies was able to neutralize viral entry. An in vivo study indicated that the treatment of mice with the PCSK9 inhibitor SBC-115076 promoted PRV proliferation. The data from the study indicate that PRV hijacks LDLR for viral entry through the activation of SREBPs.IMPORTANCEPseudorabies virus (PRV) is a herpesvirus that primarily manifests as fever, pruritus, and encephalomyelitis in various domestic and wild animals. Owing to its lifelong latent infection characteristics, PRV outbreaks have led to significant financial setbacks in the global pig industry. There is evidence that PRV variant strains can infect humans, thereby crossing the species barrier. Therefore, gaining deeper insights into PRV pathogenesis and developing updated strategies to contain its spread are critical. This study posits that the low-density lipoprotein receptor (LDLR) could be a co-receptor for PRV infection. Hence, strategies targeting LDLR may provide a promising avenue for the development of effective PRV vaccines and therapeutic interventions.

Herbal Substances with Antiviral Effects: Features and Prospects for the Treatment of Viral Diseases with Emphasis on Pro-Inflammatory Cytokines

Viral diseases have a significant impact on human health, and three novel coronaviruses (CoV) have emerged during the 21st century. In this review, we have emphasized the potential of herbal substances with antiviral effects. Our investigation focused on the features and prospects of viral disease treatment, with a particular emphasis on proinflammatory cytokines. We conducted comprehensive searches of various databases, including Science Direct, CABI Direct, Web of Science, PubMed, and Scopus. Cytokine storm mechanisms play a crucial role in inducing a pro-inflammatory response by triggering the expression of cytokines and chemokines. This response leads to the recruitment of leukocytes and promotes antiviral effects, forming the first line of defense against viruses. Numerous studies have investigated the use of herbal medicine candidates as immunomodulators or antivirals. However, cytokine-storm-targeted therapy is recommended for patients with acute respiratory distress syndrome caused by SARS-CoV to survive severe pulmonary failure. Our reviews have demonstrated that herbal formulations could serve as alternative medicines and significantly reduce complicated viral infections. Furthermore, they hold promising potential as specific antiviral agents in experimental animal models.

A Reappraisal of the Antiviral Properties of and Immune Regulation through Dietary Phytochemicals

In the present era of the COVID-19 pandemic, viral infections remain a major cause of morbidity and mortality worldwide. In this day and age, viral infections are rampant and spreading rapidly. Among the most aggressive viral infections are ebola, AIDS (acquired immunodeficiency syndrome), influenza, and SARS (severe acute respiratory syndrome). Even though there are few treatment options for viral diseases, most of the antiviral therapies are ineffective owing to frequent mutations, the development of more aggressive strains, drug resistance, and possible side effects. Traditionally, herbal remedies have been used by healers, including for dietary and medicinal purposes. Many clinical and scientific studies have demonstrated the therapeutic potential of plant-derived natural compounds. Because of unsafe practices like blood transfusions and organ transplants from infected patients, medical supply contamination. Our antiviral therapies cannot achieve sterile immunity, and we have yet to find a cure for these pernicious infections. Herbs have been shown to improve therapeutic efficacy against a wide variety of viral diseases because of their high concentration of immunomodulatory phytochemicals (both immunoinhibitory and anti-inflammatory). Combined with biotechnology, this folk medicine system can lead to the development of novel antiviral drugs and therapies. In this Review, we will summarize some selected bioactive compounds with probable mechanisms of their antiviral actions, focusing on the immunological axis of these compounds.

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.

Involvement of cell surface glycosaminoglycans in chebulagic acid's and punicalagin's antiviral activities against Coxsackievirus A16 infection

BACKGROUND

Coxsackievirus A16 (CVA16) is responsible for several recent outbreaks of Hand, Foot, and Mouth Disease in the Asia-Pacific region, and there are currently no vaccines or specific treatments available. We have previously identified two tannins, chebulagic acid (CHLA) and punicalagin (PUG), as efficient entry inhibitors against multiple viruses known to engage cell surface glycosaminoglycans (GAGs). Interestingly, these two phytochemicals could also block enterovirus infection by directly inactivating CVA16 virions, which were recently reported to utilize GAGs to mediate its entry.

PURPOSE

The aim of this study is to evaluate the involvement of GAGs in the anti-CVA16 activities of CHLA and PUG.

METHODS

To explore a potential mechanistic link, the role of GAGs in promoting CVA16 entry was first confirmed by treating human rhabdomyosarcoma (RD) cells with soluble heparin or GAG lyases including heparinase and chondroitinase. We then performed a combination treatment of CHLA or PUG with the GAG interaction inhibitors to assess whether CHLA's and PUG's anti-CVA16 activities were related to GAG competition. Molecular docking and surface plasmon resonance (SPR) were conducted to analyze the interactions between CHLA, PUG, and CVA16 capsid. Lastly, CRISPR/Cas9 knockout (KO) of the Exostosin glycosyltransferase 1 (EXT1) gene, which encodes a transmembrane glycosyltransferase involved in heparan sulfate biosynthesis, was used to validate the importance of GAGs in CHLA's and PUG's antiviral effects.

RESULTS

Intriguingly, combining GAG inhibition via heparin/GAG lyases treatments with CHLA and PUG revealed that their inhibitory activities against CVA16 infection were overlapping. Further molecular docking analysis indicated that the predicted binding sites of CHLA and PUG on the CVA16 capsid are in proximity to the putative residues recognized for GAG interaction, thus pointing to potential interference with the CVA16-GAG association. SPR analysis also confirmed the direct binding of CHLA and PUG to CVA16 capsid. Finally, RD cells with EXT1 KO decreased CHLA's and PUG's antiviral effect on CVA16 infection.

CONCLUSION

Altogether, our results suggest that CHLA and PUG bind to CVA16 capsid and prevent the virus' interaction with heparan sulfate and chondroitin sulfate for its entry. This study provides mechanistic insight into the antiviral activity of CHLA and PUG against CVA16, which may be helpful for the development of antiviral strategies against the enterovirus.

Enterovirus D68 capsid formation and stability requires acidic compartments

IMPORTANCE

The respiratory picornavirus enterovirus D68 is a causative agent of acute flaccid myelitis, a childhood paralysis disease identified in the last decade. Poliovirus, another picornavirus associated with paralytic disease, is a fecal-oral virus that survives acidic environments when passing from host to host. Here, we follow up on our previous work showing a requirement for acidic intracellular compartments for maturation cleavage of poliovirus particles. Enterovirus D68 requires acidic vesicles for an earlier step, assembly, and maintenance of viral particles themselves. These data have strong implications for the use of acidification blocking treatments to combat enterovirus diseases.

Targeting SARS-CoV-2 Non-Structural Proteins

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an enveloped respiratory β coronavirus that causes coronavirus disease (COVID-19), leading to a deadly pandemic that has claimed millions of lives worldwide. Like other coronaviruses, the SARS-CoV-2 genome also codes for non-structural proteins (NSPs). These NSPs are found within open reading frame 1a (ORF1a) and open reading frame 1ab (ORF1ab) of the SARS-CoV-2 genome and encode NSP1 to NSP11 and NSP12 to NSP16, respectively. This study aimed to collect the available literature regarding NSP inhibitors. In addition, we searched the natural product database looking for similar structures. The results showed that similar structures could be tested as potential inhibitors of the NSPs.

Effectiveness of Kabasura Kudineer tablets in the management of asymptomatic and mild cases of COVID-19: A pilot double-blinded, randomized controlled trial

INTRODUCTION

COVID-19 was declared a pandemic in 2020. It has had a devastating effect on human life and the global economy. To date, there is no proven therapy for COVID-19, even though rigorous research is ongoing to test multiple compounds across all systems of medicine. A need was felt to systematically explore the Indian system of medicine to assess its efficacy against COVID-19. The objective of the present study was to examine the effect of Kabasura Kudineer as a standalone therapy on the following: time required to achieve symptom relief & resolution, virological clearance, and levels of IL6, CRP and IgG, and compare it to the standard therapy available for treatment of COVID-19.

METHODOLOGY

A double-blinded randomized controlled trial was conducted in 110 participants. 55 participants were enrolled in the Kabasura Kudineer arm and 55 in the control (standard therapy + Kabasura Kudineer placebo) arm. Study participants were randomly allocated into the two study arms. They were assessed for symptoms at baseline, and on Day 5 and Day 10. RT PCR, CRP, IL6 and IgG levels were measured at baseline, Day 5 and Day 10. On day 28, participants were interviewed telephonically for symptom assessment alone.

STATISTICAL ANALYSIS

A per-protocol approach was used. Significant difference between two groups was assessed at baseline, day 5 and day 10 using the Chi-square and Mann Whitney test.

RESULT

A total of 110 patients participated in study. Four patients in the Kabasura Kudineer arm and 9 in the Standard therapy arm were lost to follow-up. Baseline characteristics for both the groups were matched at baseline. 83.9% and 93.9% patients were relieved of all symptoms by the 10th day in Kabasura and standard therapy groups respectively. Decrease in CRP level was more pronounced in the Kabasura group compared to standard therapy viz. 3 mg/l and 1.26 mg/l. No significant difference was found in IgG level and IL6 levels in both the study groups. However, it was noticed that among the unvaccinated group, the surge in IgG levels was much higher in Kabasura Kudineer group than the standard therapy group.

CONCLUSION

Kabasura Kudineer as a standalone therapy was as effective and safe as the standard therapy among patients with asymptomatic to mild COVID-19.

Potential medicinal plants to combat viral infections: A way forward to environmental biotechnology

The viral diseases encouraged scientific community to evaluate the natural antiviral bioactive components rather than protease inhibitors, harmful organic molecules or nucleic acid analogues. For this purpose, medicinal plants have been gaining tremendous importance in the field of attenuating the various kinds of infectious and non-infectious diseases. Most of the commonly used medicines contains the bioactive components/phytoconstituents that are generally extracted from medicinal plants. Moreover, the medicinal plants offer many advantages for the recovery applications of infectious disease especially in viral infections including HIV-1, HIV-2, Enterovirus, Japanese Encephalitis Virus, Hepatitis B virus, Herpes Virus, Respiratory syncytial virus, Chandipura virus and Influenza A/H1N1. Considering the lack of acceptable drug candidates and the growing antimicrobial resistance to existing drug molecules for many emerging viral diseases, medicinal plants may offer best platform to develop sustainable/efficient/economic alternatives against viral infections. In this regard, for exploring and analyzing large volume of scientific data, bibliometric analysis was done using VOS Viewer shedding light on the emerging areas in the field of medicinal plants and their antiviral activity. This review covers most of the plant species that have some novel bioactive compound like gnidicin, gniditrin, rutin, apigenin, quercetin, kaempferol, curcumin, tannin and oleuropin which showed high efficacy to inhibit the several disease causing virus and their mechanism of action in HIV, Covid-19, HBV and RSV were discussed. Moreover, it also delves the in-depth mechanism of medicinal with challenges and future prospective. Therefore, this work delves the key role of environment in the biological field.

Enterovirus D68 capsid formation and stability requires acidic compartments

Enterovirus D68 (EV-D68), a picornavirus traditionally associated with respiratory infections, has recently been linked to a polio-like paralytic condition known as acute flaccid myelitis (AFM). EV-D68 is understudied, and much of the field's understanding of this virus is based on studies of poliovirus. For poliovirus, we previously showed that low pH promotes virus capsid maturation, but here we show that, for EV-D68, inhibition of compartment acidification during a specific window of infection causes a defect in capsid formation and maintenance. These phenotypes are accompanied by radical changes in the infected cell, with viral replication organelles clustering in a tight juxtanuclear grouping. Organelle acidification is critical during a narrow window from 3-4hpi, which we have termed the "transition point," separating translation and peak RNA replication from capsid formation, maturation and egress. Our findings highlight that acidification is crucial only when vesicles convert from RNA factories to virion crucibles.

Strictinin: A Key Ingredient of Tea

Strictinin is a relatively tiny ellagitannin, which is found in many plants as a minor constituent. Catechins are known as the major constituents in the young leaves of most tea plants, while strictinin was found as a major constituent in the Pu'er tea plant. In some Pu'er tea varieties, strictinin was identified as the most abundant phenolic compound rather than catechins. In the past decade, strictinin was demonstrated to possess several functional activities, including antiviral, antibacterial, anti-obesity, laxative, anticaries, anti-allergic, antipsoriatic, antihyperuricemia, antidiabetic, and anticancer effects. These functional activities were in accordance with the therapeutic effects empirically perceived for Pu'er tea. Evidently, strictinin is the key ingredient in Pu'er tea that acts as a herbal medicine. In functionally-based applications, an instant powder of Pu'er tea infusion was formulated as an active raw material to be supplemented in food, cosmetics, and beverages; a new type of tea named Bitter Citrus Tzen Tea was developed by combining three teas empirically consumed to expel the cold, and new edible oral care products were designed for caries prevention by supplementation with Pu'er tea extract. More functional activities and practical applications of strictinin are scientifically anticipated in follow-up research.

Anti-COVID-19 Potential of Ellagic Acid and Polyphenols of Punica granatum L

Pomegranate (Punica granatum L.) is a rich source of polyphenols, including ellagitannins and ellagic acid. The plant is used in traditional medicine, and its purified components can provide anti-inflammatory and antioxidant activity and support of host defenses during viral infection and recovery from disease. Current data show that pomegranate polyphenol extract and its ellagitannin components and metabolites exert their beneficial effects by controlling immune cell infiltration, regulating the cytokine secretion and reactive oxygen and nitrogen species production, and by modulating the activity of the NFκB pathway. In vitro, pomegranate extracts and ellagitannins interact with and inhibit the infectivity of a range of viruses, including SARS-CoV-2. In silico docking studies show that ellagitannins bind to several SARS-CoV-2 and human proteins, including a number of proteases. This warrants further exploration of polyphenol-viral and polyphenol-host interactions in in vitro and in vivo studies. Pomegranate extracts, ellagitannins and ellagic acid are promising agents to target the SARS-CoV-2 virus and to restrict the host inflammatory response to viral infections, as well as to supplement the depleted host antioxidant levels during the stage of recovery from COVID-19.

Host Cell Targets for Unconventional Antivirals against RNA Viruses

The recent COVID-19 crisis has highlighted the importance of RNA-based viruses. The most prominent members of this group are SARS-CoV-2 (coronavirus), HIV (human immunodeficiency virus), EBOV (Ebola virus), DENV (dengue virus), HCV (hepatitis C virus), ZIKV (Zika virus), CHIKV (chikungunya virus), and influenza A virus. With the exception of retroviruses which produce reverse transcriptase, the majority of RNA viruses encode RNA-dependent RNA polymerases which do not include molecular proofreading tools, underlying the high mutation capacity of these viruses as they multiply in the host cells. Together with their ability to manipulate the immune system of the host in different ways, their high mutation frequency poses a challenge to develop effective and durable vaccination and/or treatments. Consequently, the use of antiviral targeting agents, while an important part of the therapeutic strategy against infection, may lead to the selection of drug-resistant variants. The crucial role of the host cell replicative and processing machinery is essential for the replicative cycle of the viruses and has driven attention to the potential use of drugs directed to the host machinery as therapeutic alternatives to treat viral infections. In this review, we discuss small molecules with antiviral effects that target cellular factors in different steps of the infectious cycle of many RNA viruses. We emphasize the repurposing of FDA-approved drugs with broad-spectrum antiviral activity. Finally, we postulate that the ferruginol analog (18-(phthalimide-2-yl) ferruginol) is a potential host-targeted antiviral.

Impact of Pomegranate on Probiotic Growth, Viability, Transcriptome and Metabolism

Despite rising interest in understanding intestinal bacterial survival in situ, relatively little attention has been devoted to deciphering the interaction between bacteria and functional food ingredients. Here, we examined the interplay between diverse beneficial Lactobacillaceae species and a pomegranate (POM) extract and determined the impact of this functional ingredient on bacterial growth, cell survival, transcription and target metabolite genesis. Three commercially available probiotic strains (Lactobacillus acidophilus NCFM, Lacticaseibacillus rhamnosus GG and Lactiplantibacillus plantarum Lp-115) were used in growth assays and flow cytometry analysis, indicating differential responses to the presence of POM extract across the three strains. The inclusion of POM extract in the growth medium had the greatest impact on L. acidophilus cell counts. LIVE/DEAD staining determined significantly fewer dead cells when L. acidophilus was grown with POM extract compared to the control with no POM (1.23% versus 7.23%). Whole-transcriptome analysis following exposure to POM extract showed markedly different global transcriptome responses, with 15.88% of the L. acidophilus transcriptome, 19.32% of the L. rhamnosus transcriptome and only 2.37% of the L. plantarum transcriptome differentially expressed. We also noted strain-dependent metabolite concentrations in the medium with POM extract compared to the control medium for punicalagin, ellagic acid and gallic acid. Overall, the results show that POM extract triggers species-specific responses by probiotic strains and substantiates the rising interest in using POM as a prebiotic compound.

Strictinin, a Major Ingredient in Yunnan Kucha Tea Possessing Inhibitory Activity on the Infection of Mouse Hepatitis Virus to Mouse L Cells

Theacrine and strictinin of Yunnan Kucha tea prepared from a mutant variety of wild Pu'er tea plants were two major ingredients responsible for the anti-influenza activity. As the COVID-19 outbreak is still lurking, developing safe and cost-effective therapeutics is an urgent need. This study aimed to evaluate the effects of these tea compounds on the infection of mouse hepatitis virus (MHV), a β-coronavirus serving as a surrogate for SARS-CoV. Treatment with strictinin (100 μM), but not theacrine, completely eliminated MHV infection, as indicated by a pronounced reduction in plaque formation, nucleocapsid protein expression, and progeny production of MHV. Subsequently, a time-of-drug addition protocol, including pre-, co-, or post-treatment, was exploited to further evaluate the possible mechanism of antiviral activity mediated by strictinin, and remdesivir, a potential drug for the treatment of SARS-CoV-2, was used as a positive control against MHV infection. The results showed that all three treatments of remdesivir (20 μM) completely blocked MHV infection. In contrast, no significant effect on MHV infection was observed when cells were pre-treated with strictinin (100 μM) prior to infection, while significant inhibition of MHV infection was observed when strictinin was introduced upon viral adsorption (co-treatment) and after viral entry (post-treatment). Of note, as compared with the co-treatment group, the inhibitory effect of strictinin was more striking in the post-treatment group. These results indicate that strictinin suppresses MHV infection by multiple mechanisms; it possibly interferes with viral entry and also critical step(s) of viral infection. Evidently, strictinin significantly inhibited MHV infection and might be a suitable ingredient for protection against coronavirus infection.

Electrostatic Surface Potential as a Key Parameter in Virus Transmission and Evolution: How to Manage Future Virus Pandemics in the Post-COVID-19 Era

Virus-cell interactions involve fundamental parameters that need to be considered in strategies implemented to control viral outbreaks. Among these, the surface electrostatic potential can give valuable information to deal with new epidemics. In this article, we describe the role of this key parameter in the hemagglutination of red blood cells and in the co-evolution of synaptic receptors and neurotransmitters. We then establish the functional link between lipid rafts and the electrostatic potential of viruses, with special emphasis on gangliosides, which are sialic-acid-containing, electronegatively charged plasma membrane components. We describe the common features of ganglioside binding domains, which include a wide variety of structures with little sequence homology but that possess key amino acids controlling ganglioside recognition. We analyze the role of the electrostatic potential in the transmission and intra-individual evolution of HIV-1 infections, including gatekeeper and co-receptor switch mechanisms. We show how to organize the epidemic surveillance of influenza viruses by focusing on mutations affecting the hemagglutinin surface potential. We demonstrate that the electrostatic surface potential, by modulating spike-ganglioside interactions, controls the hemagglutination properties of coronaviruses (SARS-CoV-1, MERS-CoV, and SARS-CoV-2) as well as the structural dynamics of SARS-CoV-2 evolution. We relate the broad-spectrum antiviral activity of repositioned molecules to their ability to disrupt virus-raft interactions, challenging the old concept that an antibiotic or anti-parasitic cannot also be an antiviral. We propose a new concept based on the analysis of the electrostatic surface potential to develop, in real time, therapeutic and vaccine strategies adapted to each new viral epidemic.

Traditional Tibetan medicine to fight against COVID-19: Basic theory and therapeutic drugs

The Coronavirus Diseases 2019 (COVID-19) has been rapidly spreading globally and has caused severe harm to the health of people and a substantial social burden. In response to this situation, experts around the world have considered various treatments, including the use of traditional medicine. Traditional Tibetan medicine (TTM), one of the traditional medicines in China, has played an important role in the treatment of infectious diseases in history. It has formed a solid theoretical foundation and accumulated rich experience in the treatment of infectious diseases. In this review, we provide a comprehensive introduction to the basic theory, treatment strategies, and commonly used drugs of TTM for the treatment of COVID-19. In addition, the efficacies and potential mechanisms of these TTM drugs against COVID-19 are discussed based on available experimental data. This review may provide important information for the basic research, clinical application and drug development of traditional medicines for the treatment of COVID-19 or other infectious diseases. More pharmacological studies are needed to reveal the therapeutic mechanisms and active ingredients of TTM drugs in the treatment of COVID-19.

Phytocompounds as a source for the development of new drugs to treat respiratory viral infections

Respiratory viruses have an important history as a threat to global health. However, this problem has been aggravated due to the appearance of new outbreaks caused by a newly discovered virus or variant. Recently, the new coronavirus (SARS-CoV-2) has been a major concern for health authorities, and it was classified as a pandemic by the World Health Organization. Secondary metabolites obtained from plants represent an alternative to the discovery of new active molecules and have already shown potential to combat different viruses. In an effort to demonstrate the broad spectrum of antiviral action from these metabolites, this work describes the compounds that were effective against the major viruses that cause respiratory infections in humans. In addition, their mechanisms of action were highlighted as an approach to better understanding the virus-bioactive substance relationship. Finally, this study warns that, although phytocompounds have a broad antiviral action spectrum, the development of products and clinical trials based on these secondary metabolites is still scarce and therefore deserves greater attention from the scientific community.

Punica granatum Peel and Leaf Extracts as Promising Strategies for HSV-1 Treatment

Punica granatum is a rich source of bioactive compounds which exhibit various biological effects. In this study, pomegranate peel and leaf ethanolic crude extracts (PPE and PLE, respectively) were phytochemically characterized and screened for antioxidant, antimicrobial and antiviral activity. LC-PDA-ESI-MS analysis led to the identification of different compounds, including ellagitannins, flavonoids and phenolic acids. The low IC₅₀ values, obtained by DPPH and FRAP assays, showed a noticeable antioxidant effect of PPE and PLE comparable to the reference standards. Both crude extracts and their main compounds (gallic acid, ellagic acid and punicalagin) were not toxic on Vero cells and exhibited a remarkable inhibitory effect on herpes simplex type 1 (HSV-1) viral plaques formation. Specifically, PPE inhibited HSV-1 adsorption to the cell surface more than PLE. Indeed, the viral DNA accumulation, the transcription of viral genes and the expression of viral proteins were significantly affected by PPE treatment. Amongst the compounds, punicalagin, which is abundant in PPE crude extract, inhibited HSV-1 replication, reducing viral DNA and transcripts accumulation, as well as proteins of all three phases of the viral replication cascade. In contrast, no antibacterial activity was detected. In conclusion, our findings indicate that Punica granatum peel and leaf extracts, especially punicalagin, could be a promising therapeutic candidate against HSV-1.

Discovery and structural characterization of chicoric acid as a SARS-CoV-2 nucleocapsid protein ligand and RNA binding disruptor

The nucleocapsid (N) protein plays critical roles in coronavirus genome transcription and packaging, representing a key target for the development of novel antivirals, and for which structural information on ligand binding is scarce. We used a novel fluorescence polarization assay to identify small molecules that disrupt the binding of the N protein to a target RNA derived from the SARS-CoV-2 genome packaging signal. Several phenolic compounds, including L-chicoric acid (CA), were identified as high-affinity N-protein ligands. The binding of CA to the N protein was confirmed by isothermal titration calorimetry, ¹H-STD and ¹⁵N-HSQC NMR, and by the crystal structure of CA bound to the N protein C-terminal domain (CTD), further revealing a new modulatory site in the SARS-CoV-2 N protein. Moreover, CA reduced SARS-CoV-2 replication in cell cultures. These data thus open venues for the development of new antivirals targeting the N protein, an essential and yet underexplored coronavirus target.

Repurposing of the herbal formulations: molecular docking and molecular dynamics simulation studies to validate the efficacy of phytocompounds against SARS-CoV-2 proteins

Herbal formulations mentioned in traditional medicinal texts were investigated for in silico effect against SARS-COV-2 proteins involved in various functions of a virus such as attachment, entry, replication, transcription, etc. To repurpose and validate polyherbal formulations, molecular docking was performed to study the interactions of more than 150 compounds from various formulations against the SARS-CoV-2 proteins. Molecular dynamics (MD) simulation was performed to evaluate the interaction of top scored ligands with the various receptor proteins. The docking results showed that Liquiritic acid, Liquorice acid, Terchebulin, Glabrolide, Casuarinin, Corilagin, Chebulagic acid, Neochebulinic acid, Daturataturin A, and Taraxerol were effective against SARS-COV-2 proteins with higher binding affinities with different proteins. Results of MD simulations validated the stability of ligands from potent formulations with various receptors of SARS-CoV-2. Binding free energy analysis suggested the favourable interactions of phytocompounds with the recpetors. Besides, in silico comparison of the various formulations determined that Pathyadi kwath, Sanjeevani vati, Yashtimadhu, Tribhuvan Keeratiras, and Septillin were more effective than Samshamni vati, AYUSH-64, and Trikatu. Polyherbal formulations having anti-COVID-19 potential can be used for the treatment with adequate monitoring. New formulations may also be developed for systematic trials based on ranking from these studies.Communicated by Ramaswamy H. Sarma.

Passive antifouling and active self-disinfecting antiviral surfaces

Viruses pose a serious threat to human health and society in general, as virus infections are one of the main causes of morbidity and mortality. Till May 2022, over 513 million people around the world have been confirmed to be infected and more than 6.2 million have died due to SARS-CoV-2. Although the COVID-19 pandemic will be defeated in the near future, we are likely to face new viral threats in the coming years. One of the important instruments to protect from viruses are antiviral surfaces, which are essentially capable of limiting their spread. The formulation of the concept of antiviral surfaces is relatively new. In general, five types of mechanism directed against virus spread can be proposed for antiviral surfaces; involving: direct and indirect actions, receptor inactivation, photothermal effect, and antifouling behavior. All antiviral surfaces can be classified into two main types - passive and active. Passive antiviral surfaces are based on superhydrophobic coatings that are able to repel virus contaminated droplets. In turn, viruses can become biologically inert (e.g., blocked or destroyed) upon contact with active antiviral surfaces, as they contain antiviral agents: metal atoms, synthetic or natural polymers, and small molecules. The functionality of antiviral surfaces can be significantly improved with additional properties, such as temperature- or pH-responsivity, multifunctionality, non-specific action on different virus types, long-term application, high antiviral efficiency and self-cleaning.

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.

Pomegranate Wastes Are Rich in Bioactive Compounds with Potential Benefit on Human Health

Pomegranate use is increasing worldwide, as it is considered a tasteful healthy food. It is mainly used as fruit, juice, and jam. The pomegranate peel represents about 40–50% of the total fruit weight and contains numerous and diverse bioactive substances. The aim of this research was to analyze the pomegranate peel chemical composition of Wonderful cultivated in Southern Italy and treated with an innovative physic dry concentration procedure in comparison with the peel composition of freeze-dried Wonderful cultivated in Southern Italy, freeze-dried Wonderful cultivated in South Africa, and freeze-dried pomegranate cultivated in India. The specific aim was to verify how much the growth area, cultivar type, and dry procedure influenced the chemical composition of the peels in terms of valuable bioactive compounds. Spectrophotometric and HPLC identification methods were used to detect antioxidants, antioxidant activities, and phenolic and flavonoid components. Results evidenced that in pomegranate peels of Wonderful cultivated in Calabria and dried with the innovative process, total phenolic substances, total flavonoids, vitamin C, vitamin E, and antioxidant activities were the highest. Great amounts of single phenolic acids and flavonoids were found in Calabrian Wonderful peels dried with the innovative process. Overall, it emerged that a great amount of bioactive and diverse compounds found in Calabrian Wonderful pomegranate peel comes from the niche pedoclimatic conditions, and the physic drying innovative methodology turned out to be an advantageous procedure to concentrate and conserve biocompounds.

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.

Tale of Viruses in Male Infertility

Male infertility is a condition where the males either become sterile or critically infertile. The World Health Organisation assessed that approximately 9% of the couple have fertility issues where the contribution of the male partner was estimated to be 50%. There are several factors that can amalgamate to give rise to male infertility. Among them are lifestyle factors, genetic factors and as well as several environmental factors. The causes of male infertility may be acquired, congenital or sometimes idiopathic. All these factors adversely affect the spermatogenesis process as well as they impart serious threats to male genital organs thus resulting in infertility. Viruses are submicroscopic pathogenic agents that rely on host for their replication and survival. They enter the host cell, hijack the host cell machinery to aid their own replication and exit the cell for a new round of infection. With the growing abundance of different types of viruses and the havoc they have stirred in the form of pandemics, it is very essential to decipher their route of entry inside the human body and understand their diverse functional roles in order to combat them. In this chapter, we will review how viruses invade the male genital system thus in turn leading to detrimental consequence on male fertility. We will discuss the tropism of various viruses in the male genital organs and explore their sexual transmissibility. This chapter will summarise the functional and mechanistic approaches employed by the viruses in inducing oxidative stress inside spermatozoa thus leading to male infertility. Moreover, we will also highlight the various antiviral therapies that have been studied so far in order to ameliorate viral infection in order to combat the harmful consequences leading to male infertility.

Plant-Derived Natural Products as Lead Agents against Common Respiratory Diseases

Never has the world been more challenged by respiratory diseases (RDs) than it has witnessed in the last few decades. This is evident in the plethora of acute and chronic respiratory conditions, ranging from asthma and chronic obstructive pulmonary disease (COPD) to multidrug-resistant tuberculosis, pneumonia, influenza, and more recently, the novel coronavirus (COVID-19) disease. Unfortunately, the emergence of drug-resistant strains of pathogens, drug toxicity and side effects are drawbacks to effective chemotherapeutic management of RDs; hence, our focus on natural sources because of their unique chemical diversities and novel therapeutic applications. This review provides a summary on some common RDs, their management strategies, and the prospect of plant-derived natural products in the search for new drugs against common respiratory diseases.

Combination of Ephedra sinica stems and Terminalia chebula fruits produces new ephedrine derivatives in vivo that diminish the permeability to BBB while retaining airway dilation and hepatoprotective effects

ETHNOPHARMACOLOGICAL RELEVANCE

The stems of Ephedra sinica and the fruits of Terminalia chebula are combined using in traditional Mongolian medicine formula "Gurigumu-7" for liver diseases. E. sinica stems contains ephedrine with broncho-dilatory activity. However, ephedrine can pass through the blood-brain barrier (BBB) and excite the central nervous system (CNS) to cause insomnia and restlessness.

AIM OF THE STUDY

The present study was to investigate the structures and bioactivities of new compounds formed in vivo after co-administration of E. sinica stems and T. chebula fruits.

MATERIALS AND METHODS

Pharmacokinetic investigation was carried out in rats. A parallel artificial membrane permeability measurement system was used to determine BBB permeability. Ex vivo experiments using tracheal rings of guinea pig was performed to examine the tracheal relaxation effect. In vivo hepatoprotective tests were carried out in Tg (fabp10a: dsRed) liver transgenic zebrafish. The fluorescent probe, 2,7-dichlorodihydrofluorescein diacetate, was used to measure reactive oxygen species, and UHPLC-MS was used to determine glutathione concentrations after derivatization with N-ethylmaleimide.

RESULTS

New ephedrine derivatives (1 and 2) formed in vivo and reached their maximum serum concentrations at 0.5 h after administration of the two herbal drugs. Compounds 1 and 2 showed lower BBB permeability than ephedrine, suggesting that they have less adverse effects on the CNS. Compounds 1 and 2 relaxed the tracheal rings and had strong hepatoprotective effect on transgenic zebrafish with liver specific expression of RFP. Compounds 1 and 2 significantly reduced the level of reactive oxygen species while increasing that of glutathione in thioacetamide-treated zebrafish, which might be the hepatoprotective mechanism.

CONCLUSION

These results provided evidences that the chemical constituents in various herbal drugs in a medicinal formula can interact to generate new compounds with fewer side effects and increased or additive bioactivity.

Pharmacology and toxicology of tannins

Tannins are an interesting class of polyphenols, characterized, in almost all cases, by a different degree of polymerization, which, inevitably, markedly influences their bioavailability, as well as biochemical and pharmacological activities. They have been used for the process of tanning to transform hides into leather, from which their name derives. For several time, they have not been accurately evaluated, but now researchers have started to unravel their potential, highlighting anti-inflammatory, antimicrobial, antioxidant and anticancer activities, as well as their involvement in cardiovascular, neuroprotective and in general metabolic diseases prevention. The mechanisms underlying their activity are often complex, but the main targets of their action (such as key enzymes modulation, activation of metabolic pathways and changes in the metabolic fluxes) are highlighted in this review, without losing sight of their toxicity. This aspect still needs further and better-designed study to be thoroughly understood and allow a more conscious use of tannins for human health.

Hepatitis C Virus NS3/4A Inhibition and Host Immunomodulation by Tannins from Terminalia chebula: A Structural Perspective

Terminalia chebula Retz. forms a key component of traditional folk medicine and is also reported to possess antihepatitis C virus (HCV) and immunomodulatory activities. However, information on the intermolecular interactions of phytochemicals from this plant with HCV and human proteins are yet to be established. Thus, by this current study, we investigated the HCV NS3/4A inhibitory and host immune-modulatory activity of phytocompounds from T. chebula through in silico strategies involving network pharmacology and structural bioinformatics techniques. To start with, the phytochemical dataset of T. chebula was curated from biological databases and the published literature. Further, the target ability of the phytocompounds was predicted using BindingDB for both HCV NS3/4A and other probable host targets involved in the immune system. Further, the identified targets were docked to the phytochemical dataset using AutoDock Vina executed through the POAP pipeline. The resultant docked complexes with significant binding energy were subjected to 50 ns molecular dynamics (MD) simulation in order to infer the stability of complex formation. During network pharmacology analysis, the gene set pathway enrichment of host targets was performed using the STRING and Reactome pathway databases. Further, the biological network among compounds, proteins, and pathways was constructed using Cytoscape 3.6.1. Furthermore, the druglikeness, side effects, and toxicity of the phytocompounds were also predicted using the MolSoft, ADVERpred, and PreADMET methods, respectively. Out of 41 selected compounds, 10 were predicted to target HCV NS3/4A and also to possess druglike and nontoxic properties. Among these 10 molecules, Chebulagic acid and 1,2,3,4,6-Pentagalloyl glucose exhibited potent HCV NS3/4A inhibitory activity, as these scored a lowest binding energy (BE) of −8.6 kcal/mol and −7.7 kcal/mol with 11 and 20 intermolecular interactions with active site residues, respectively. These findings are highly comparable with Asunaprevir (known inhibitor of HCV NS3/4A), which scored a BE of −7.4 kcal/mol with 20 key intermolecular interactions. MD studies also strongly suggest that chebulagic acid and 1,2,3,4,6-Pentagalloyl glucose as promising leads, as these molecules showed stable binding during 50 ns of production run. Further, the gene set enrichment and network analysis of 18 protein targets prioritized 10 compounds and were predicted to potentially modulate the host immune system, hemostasis, cytokine levels, interleukins signaling pathways, and platelet aggregation. On overall analysis, this present study predicts that tannins from T. chebula have a potential HCV NS3/4A inhibitory and host immune-modulatory activity. However, further experimental studies are required to confirm the efficacies.

Anti-HCV Tannins From Plants Traditionally Used in West Africa and Extracted With Green Solvents

Millions of people are still infected with hepatitis C virus (HCV) nowadays. Although recent antivirals targeting HCV proteins are very efficient, they are not affordable for many people infected with this virus. Therefore, new and more accessible treatments are needed. Several Ivorian medicinal plants are traditionally used to treat “yellow malaria”, a nosological category including illness characterized by symptomatic jaundice such as hepatitis. Therefore, some of these plants might be active against HCV. An ethnobotanical survey in Côte d’Ivoire allowed us to select such medicinal plants. Those were first extracted with methanol and tested for their anti-HCV activity. The most active ones were further studied to specify their IC50 and to evaluate their toxicity in vitro. Greener solvents were tested to obtain extracts with similar activities. Following a phytochemical screening, tannins of the most active plants were removed before re-testing on HCV. Some of these tannins were identified by UPLC-MS and pure molecules were tested against HCV. Out of the fifteen Ivorian medicinal plants selected for their putative antiviral activities, Carapa procera DC. and Pericopsis laxiflora (Benth. ex Baker) Meeuwen were the most active against HCV (IC50: 0.71 and 0.23 μg/ml respectively) and not toxic for hepatic cells. Their crude extracts were rich in polyphenols, including tannins such as procyanidins A2 which is active against HCV. The same extracts without tannin lost their anti-HCV activity. Replacing methanol by hydro-ethanolic solvent led to tannins-rich extracts with similar antiviral activities, and higher than that of aqueous extracts.

Punicalagin, a pomegranate compound, induces apoptosis and autophagy in acute leukemia

Background

Punicalagin is the major phenolic compound found in pomegranate peels. It has several reported medical benefits, including antioxidant, anti-inflammatory, and anticancer properties. The present study investigated the anti-leukemic effects and the molecular mechanism of punicalagin on NB4 and MOLT-4 leukemic cell lines.

Methods

Leukemic cells were treated with punicalagin and cell viability was determined using MTS assay. Apoptosis and autophagy were analyzed by flow cytometry using Annexin V-FITC/PI and anti-LC3/FITC antibodies staining, respectively. Apoptotic and autophagic mRNA expression were determined using reverse transcription-quantitative PCR. STITCH bioinformatics tools were used to predict the interaction between punicalagin and its proposed target proteins.

Results

Results indicated that punicalagin decreased NB4 and MOLT-4 cell viability in a dose-dependent manner. Punicalagin, in combination with daunorubicin, exhibited synergistic cytotoxic effects. Punicalagin induced apoptosis through the upregulation of caspase-3/-8/-9, Bax and the downregulation of Bcl-2 expression. Punicalagin also promoted autophagy via the downregulation of mTOR and the upregulation of ULK1 expression. Cyclooxygenase-2 and toll-like receptor 4 were found to be involved in punicalagin-induced cell death in punicalagin-targeted protein interactions.

Conclusions

These results suggest that punicalagin exerts cytotoxic activities by suppressing proliferation and promoting apoptosis and autophagy by activating the caspase cascade, altering Bax and Bcl-2, and regulating autophagy via mTOR/ULK1 signaling.

Potential antiviral effects of some native Iranian medicinal plants extracts and fractions against influenza A virus

Background

Influenza A virus (IAV) infection is a continual threat to the health of animals and humans globally. Consumption of the conventional drugs has shown several side effects and drug resistance. This study was aimed to screen some Iranian medicinal plants extracts and their fractions against influenza A virus.

Methods

Glycyrrhiza glabra (rhizome), Myrtus  commonis (leaves), Melissa officinalis (leaves), Hypericum perforatum (aerial parts), Tilia platyphyllos (flower), Salix alba (bark), and Camellia sinensis (green and fermented leaves) were extracted with 80% methanol and fractionated with chloroform and methanol, respectively. The cytotoxicity of the compounds were determined by MTT colorimetric assay on MDCK cells. The effective concentrations (EC₅₀) of the compounds were calculated from the MTT results compared to the negative control with no significant effects on cell viability. The effects of EC₅₀ of the compounds on viral surface glycoproteins and viral titer were tested by HI and HA virological assays, respectively and compared with oseltamivir and amantadine. Preliminary phytochemical analysis were done for promising anti-IAV extracts and fractions.

Results

The most effective samples against IAV titer (P ≤ 0.05) were crude extracts of G. glabra, M. officinalis and S. alba; methanol fractions of M. communis and M. officinalis; and chloroform fractions of M. communis and C. sinensis (fermented) mostly in co- and pre-penetration combined treatments. The potential extracts and fractions were rich in flavonoids, tannins, steroids and triterpenoids.

Conclusion

The outcomes confirmed a scientific basis for anti-influenza A virus capacity of the extracts and fractions from the selected plants for the first time, and correlated their effects with their phytochemical constituents. It is worth focusing on elucidating pure compounds and identifying their mechanism(s) of action.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03423-x.

Ayurveda Rasayana as antivirals and immunomodulators: potential applications in COVID-19

Coronavirus disease (COVID-19) has been declared as a pandemic by the World Health Organization with rapid spread across 216 countries. COVID-19 pandemic has left its imprints on various health systems globally and caused immense social and economic disruptions. The scientific community across the globe is in a quest for digging the effective treatment for COVID-19 and exploring potential leads from traditional systems of healthcare across the world too. Ayurveda (Indian traditional system of medicine) has a comprehensive aspect of immunity through Rasayana which is a rejuvenation therapy. Here we attempt to generate the potential leads based on the classical text from Ayurveda in general and Rasayana in particular to develop effective antiviral and/or immunomodulator for potential or adjunct therapy in SARS-CoV-2. The Rasayana acts not only by resisting body to restrain or withstand the strength, severity or progression of a disease but also by promoting power of the body to prevent the manifestation of a disease. These Rasayana herbs are common in practice as immunomodulator, antiviral and protectives. The studies on Rasayana can provide an insight into the future course of research for the plausible development of effective management of COVID-19 by the utilization and development of various traditional systems of healthcare. Keeping in view the current pandemic situation, there is an urgent need of developing potential medicines. This study proposes certain prominent medicinal plants which may be further studied for drug development process and also in clinical setup under repurposing of these herbs.

Phytomolecules Repurposed as Covid-19 Inhibitors: Opportunity and Challenges

The SARS-CoV-2 virus has spread worldwide to cause a full blown pandemic since 2020. To date, several promising synthetic therapeutics are repurposed and vaccines through different stages of clinical trials were approved and being administered, but still the efficacy of the drugs and vaccines are yet to be decoded. This article highlights the importance of traditional medicinal plants and the phytomolecules derived from them, which possess in vitro antiviral and anti-CoV properties and further explores their potential as inhibitors to molecular targets of SARS-CoV-2 that were evaluated by in silico approaches. Botanicals in traditional medicinal systems have been investigated for anti-SARS-CoV-2 activity through in silico and in vitro studies. However, information linking structure of phytomolecules to their antiviral activity is limited. Most phytomolecules with anti-CoV activity were studied for inhibition of the human ACE2 receptor through which the virus enters host cells, and non-structural proteins 3CLpro and PLpro. Although the proteases are ideal anti-CoV targets, information on plant-based inhibitors for the CoV structural proteins, e.g., spike, envelope, membrane, nucleocapsid required further investigations. In absence of scientific evaluations through in vitro and biocompatibility studies, plant-based antivirals fall short as treatment options. Plant-based anti-SARS-CoV-2 therapeutics can be promising alternatives to their synthetic counterparts as they are economical and bear fewer chances of toxicity, side effects, and viral resistance. Our review could provide a systematic overview of the potential phytomolecules which can be repurposed and subjected to further modes of experimental evaluation to qualify for use in treatment and prophylaxis of SARS-CoV-2 infections.

Food packaging wastes amid the COVID-19 pandemic: Trends and challenges

BACKGROUND

The COVID-19 crisis generated changes in consumer behavior related to food purchase and the management of food packaging. Due to the intensification of online purchases for home delivery, there has been an increase in the use of food packaging (mostly non-biodegradable or non-renewable). Moreover, the fear of contamination with SARS-CoV-2 through contact with materials and surfaces has led to an intensified disposal of food packaging, promoting a setback in waste management.

SCOPE AND APPROACH

The purpose of this short commentary is to address the impacts of increased use and disposal of food packaging during the COVID-19 pandemic. Technological solutions have been presented as tools to minimize the environmental impacts of the increased volume of disposed food packaging (namely, the development of biodegradable food packaging) as well as to minimize the occurrence of cross-contamination (namely, the incorporation of active antiviral components).

KEY FINDINGS AND CONCLUSIONS

The consumer behavior in the COVID-19 pandemic requires actions concerning adoption of bioplastics for single-use food packaging. Polylactide (PLA) stands out for high production viability, performance comparable to those of petroleum-based thermoplastics, and carbon neutral life cycle. Moreover, active components including organic compounds (resveratrol, luteolin, myricetin etc.) and metals (e.g., copper, zinc, silver) can mitigate cross-contamination. Therefore, there are opportunities to reduce food packaging-related environmental footprints while also decreasing the occurrence of surface-mediated cross-contamination.

The Methanolic Extract of Perilla frutescens Robustly Restricts Ebola Virus Glycoprotein-Mediated Entry

Ebola virus (EBOV), one of the most infectious human viruses and a leading cause of viral hemorrhagic fever, imposes a potential public health threat with several recent outbreaks. Despite the difficulties associated with working with this pathogen in biosafety level-4 containment, a protective vaccine and antiviral therapeutic were recently approved. However, the high mortality rate of EBOV infection underscores the necessity to continuously identify novel antiviral strategies to help expand the scope of prophylaxis/therapeutic management against future outbreaks. This includes identifying antiviral agents that target EBOV entry, which could improve the management of EBOV infection. Herein, using EBOV glycoprotein (GP)-pseudotyped particles, we screened a panel of natural medicinal extracts, and identified the methanolic extract of Perilla frutescens (PFME) as a robust inhibitor of EBOV entry. We show that PFME dose-dependently impeded EBOV GP-mediated infection at non-cytotoxic concentrations, and exerted the most significant antiviral activity when both the extract and the pseudoparticles are concurrently present on the host cells. Specifically, we demonstrate that PFME could block viral attachment and neutralize the cell-free viral particles. Our results, therefore, identified PFME as a potent inhibitor of EBOV entry, which merits further evaluation for development as a therapeutic strategy against EBOV infection.

From Fighting Critters to Saving Lives: Polyphenols in Plant Defense and Human Health

Polyphenols, such as flavonoids and phenolic acids, are a group of specialized metabolites in plants that largely aid in plant defense by deterring biotic stressors and alleviating abiotic stress. Polyphenols offer a wide range of medical applications, acting as preventative and active treatments for diseases such as cancers and diabetes. Recently, researchers have proposed that polyphenols may contribute to certain applications aimed at tackling challenges related to the COVID-19 pandemic. Understanding the beneficial impacts of phytochemicals, such as polyphenols, could potentially help prepare society for future pandemics. Thus far, most reviews have focused on polyphenols in cancer prevention and treatment. This review aims to provide a comprehensive discussion on the critical roles that polyphenols play in both plant chemical defense and human health based on the most recent studies while highlighting prospective avenues for future research, as well as the implications for phytochemical-based applications in both agricultural and medical fields.

Nature-derived hit, lead, and drug-like small molecules: Current status and future aspects against key target proteins of Coronaviruses

BACKGROUND

COVID-19 pandemic, the most unprecedented event of the year 2020, has brought millions of scientists worldwide in a single platform to fight against it. Though several drugs are now in the clinical trial, few vaccines available on the market already but the lack of an effect of those is making the situation worse.

AIM OF THE STUDY

In this review, we demonstrated comprehensive data of natural antiviral products showing activities against different proteins of Human Coronaviruses (HCoV) that are responsible for its pathogenesis. Furthermore, we categorized the compounds into the hit, lead, and drug based on the IC50/EC50 value, drug-likeness, and lead-likeness test to portray their potentiality to be a drug. We also demonstrated the present status of our screened antiviral compounds with respect to clinical trials and reported the lead compounds that can be promoted to clinical trial against COVID-19.

METHODS

A systematic search strategy was employed focusing on Natural Products (NPs) with proven activity (in vitro, in vivo, or in silico) against human coronaviruses, in general, and data were gathered from databases like PubMed, Web of Science, Google Scholar, SciVerse, and Scopus. Information regarding clinical trials retrieved from the Clinical Trial database.

RESULTS

Total "245" natural compounds were identified initially from the literature study. Among them, Glycyrrhizin, Caffeic acid, Curcumin is in phase 3, and Tetrandrine, Cyclosporine, Tacrolimus, Everolimus are in phase 4 clinical trial. Except for Glycyrrhizin, all compounds showed activity against COVID-19.

CONCLUSIONS

In summary, our demonstrated specific small molecules with lead and drug-like capabilities clarified their position in the drug discovery pipeline and proposed their future research against COVID-19.

Small molecules baicalein and cinnamaldehyde are potentiators of measles virus-induced breast cancer oncolysis

BACKGROUND

Although the breast cancer mortality has slowed down from 2008 to 2017, breast cancer incidence rate continues to rise and thus, new and/or improved treatments are highly needed. Among them, oncolytic virotherapy which has the ability of facilitating the antitumor adaptive immunity, appears as a promising anticancer therapy. Oncolytic measles virus (MV) is particularly suitable for targeting breast cancer due to the upregulation of MV's receptor nectin-4. Nonetheless, with limited clinical success currently, ways of boosting MV-induced breast cancer oncolysis are therefore necessary. Oncolytic virotherapy alone and combined with chemotherapeutic drugs are two strategic areas with intensive development for the search of anticancer drugs. Considering that baicalein (BAI) and cinnamaldehyde (CIN) have demonstrated antitumor properties against multiple cancers including breast cancer, they could be good partners for MV-based oncolytic virotherapy.

PURPOSE

To assess the in vitro effect of BAI and CIN with MV and assess their combination effects.

METHODS

We examined the combinatorial cytotoxic effect of oncolytic MV and BAI or CIN on MCF-7 breast cancer cells. Potential anti-MV activities of the phytochemicals were first investigated in vitro to determine the optimal combination model. Synergism of MV and BAI or CIN was then evaluated in vitro by calculating the combination indices. Finally, cell cycle analysis and apoptosis assays were performed to confirm the mechanism of synergism.

RESULTS

Overall, the viral sensitization combination modality using oncolytic MV to first infect MCF-7 breast cancer cells followed by drug treatment with BAI or CIN was found to produce significantly enhanced tumor killing. Further mechanistic studies showed that the combinations 'MV-BAI' and 'MV-CIN' display synergistic anti-breast cancer effect, mediated by elevated apoptosis.

CONCLUSION

We demonstrated, for the first time, effective combination of oncolytic MV with BAI or CIN that could be further explored and potentially developed into novel therapeutic strategies targeting nectin-4-marked breast cancer cells.

Physiological and Immune Functions of Punicalagin

The aim of this publication is to compile a summary of the findings regarding punicalagin in various tissues described thus far in the literature, with an emphasis on the effect of this substance on immune reactions. Punicalagin (PUN) is an ellagitannin found in the peel of pomegranate (Punica granatum). It is a polyphenol with proven antioxidant, hepatoprotective, anti-atherosclerotic and chemopreventive activities, antiproliferative activity against tumor cells; it inhibits inflammatory pathways and the action of toxic substances, and is highly tolerated. This work describes the source, metabolism, functions and effects of punicalagin, its derivatives and metabolites. Furthermore, its anti-inflammatory and antioxidant effects are described.

Evidence-based traditional Siddha formulations for prophylaxis and management of respiratory symptoms in COVID-19 pandemic-a review

The recent outbreak of COVID-19 is attributed to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). This viral disease is rapidly spreading across the globe, including India. The mainstay in managing the disease is supportive care, nutrition, and preventing further progression in the absence of proven antiviral drugs. Currently two vaccines Covishield and Covaxin are administered in India. Long-term plans of developing most reliable mRNA-based vaccines are also underway for the future method of prophylaxis. The Siddha system of medicine's holistic approach emphasizes lifestyle modification, prophylactic interventions, and dietary management to boost the host immunity and treatment with herbal medicines and higher-order medicines as the case may be. In this review, a brief outline of the disease COVID-19, Coronavirus, evidence-based traditional Siddha interventions for respiratory ailments and immune boosters highlighting the relevant published research on individual herbs are dealt, which pave way for further research on drug repurposing for COVID-19. Historical evidence on the prevention and treatment of infections especially antivirals in Siddha classics is studied.

Properties of Ethnomedicinal Plants and Their Bioactive Compounds: Possible Use for COVID-19 Prevention and Treatment

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has changed the global scenario. To date, there are no treatment or preventive options. The discovery of a new drug will take time. In addition, the new drug will have side effects, and the virus will gradually become resistant to it. Therefore, it is important to search for a drug with a natural origin.

OBJECTIVE

In this review, we analyzed and summarized various ethnomedicinal plants and their bioactive compounds as a source of antiviral agents for COVID-19 prevention and treatment.

METHODS

From the literature, we selected different natural compounds that can act as potential targets at low cost with broad-spectrum antiviral activity.

RESULTS

Of the 200 Chinese herbal extracts tested for their possible role against SARS-CoV, Lycoris radiata, Artemisia annua, Pyrrosia lingua, and Lindera aggregate showed anti-SARS-CoV effects with the median effective concentration = 2.4-88.2 μg/mL.

CONCLUSION

Ethnomedicinal herbs can be used as an alternative source of novel, promising antiviral agents that might directly or indirectly inhibit the COVID-19 progression.

Candidate Anti-COVID-19 Medicinal Plants from Ethiopia: A Review of Plants Traditionally Used to Treat Viral Diseases

Background

Emerging viral infections are among the major global public health concerns. The pandemic COVID-19 is a contagious respiratory and vascular disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). There are no medicines that can treat SARS-CoV-2 except the vaccines. Therefore, searching for plant-originated therapeutics for the treatment of COVID-19 is required. Consequently, reviewing medicinal plants used to treat different viral infections is mandatory. This review article aims to review the ethnobotanical knowledge of medicinal plants traditionally used to treat different viral diseases by the Ethiopian people and suggests those plants as candidates to fight COVID-19.

Methods

Articles written in English were searched from online public databases using searching terms like “Traditional Medicine,” “Ethnobotanical study,” “Active components,” “Antiviral activities,” and “Ethiopia.” Ethnobotanical data were analyzed using the Excel statistical software program.

Result

From the 46 articles reviewed, a total of 111 plant species were claimed to treat viral infections. Fifty-six (50.4%) of the plant species had reported to have antiviral active components that are promising to treat COVID-19. Lycorine, gingerol shogaol, resveratrol, rhoifolin, oleanolic acid, kaempferol, rosmarinic acid, almond oil, ursolic acid, hederagenin, nigellidine, α-hederin, apigenin, nobiletin, tangeretin, chalcone, hesperidin, epigallocatechin gallate, allicin, diallyl trisulfide, ajoene, aloenin, artemisinin, glucobrassicin, curcumin, piperine, flavonoids, anthraquinone, hydroxychloroquine, and jensenone were some of them.

Conclusion

The Ethiopian traditional knowledge applies a lot of medicinal plants to treat different viral infections. Reports of the chemical components of many of them confirm that they can be promising to fight COVID-19.

Dual-tautomerism separation method based on asymmetric transformation: Gram-scale preparation of high-purity punicalagin from pomegranate peel wastes

In this study, a special orthogonal separation method, named as dual-tautomerism separation (DTS), was developed for the purification of tautomeric compounds from complex matrixes. In DTS, isomers of these compounds are individually collected and asymmetrically transformed to the mixtures of isomers. After separating the mixture with an identical method, high-purity compounds can be prepared from the newly generated isomers but impurities remain in another one. To validate the effectiveness, a DTS was developed to prepare punicalagin in gram-scale from pomegranate peel waste. Isomerization kinetic and thermodynamic of punicalagin were accurately assayed by dynamic HPLC built on low-temperature or/and loop-based stop-flow two-dimensional liquid chromatography. After the isomerization based on it, 9.3 g of pomegranate peel extract was firstly separated on C18 column, and F_α and F_β around α-punicalagin and β-punicalagin were obtained. Then, the proportion of α-punicalagin in F_α and F_β was optimized to 52.7% and 32.0% based on isomerization kinetics and thermodynamic. With the aid of low-temperature injection, F_α and F_β were loaded and secondly purified. After waste recycling, totally 3.0 g of punicalagin with the purify of 99.5% was obtained within two days, which would strongly support the resource utilization of pomegranate peel waste. Because only an individual method was employed in the two-step purification, the separation in DTS was fully compatible.

Current Overviews on COVID-19 Management Strategies

The coronavirus pandemic has hit the world lately and caused acute respiratory syndrome in humans. The causative agent of the disease was soon brought to focus by scientists as SARS-CoV-2 and later called a novel coronavirus by the general public. Due to the severity and rapid spread of the disease, WHO classifies the COVID-19 pandemic as the 6th public health emergency even after taking efforts like worldwide quarantine and restrictions. Since only symptomatic treatment is available, the best way to control the spread of the virus is by taking preventive measures. Various types of antigen/antibody detection kits and diagnostic methods are available for the diagnosis of COVID-19 patients. In recent years, various phytochemicals and repurposing drugs are showing a broad range of anti-viral activities with different modes of action have been identified. Repurposing drugs such as arbidol, hydroxychloroquine, chloroquine, lopinavir, favipiravir, remdesivir, hexamethylene amiloride, and dexamethasone, tocilizumab, interferon-β, neutralizing antibodies exhibit in vitro anti-coronaviral properties by inhibiting multiple processes in the virus life cycle. Various research groups are involved in drug trials and vaccine development. Plant-based anti-viral compounds such as baicalin, calanolides, curcumin, oxymatrine, matrine, and resveratrol exhibit different modes of action against a wide range of positive/negative sense-RNA/DNA virus, and future researches need to be conducted to ascertain their role, use in managing SARS-CoV-2. Thus, this article is an attempt to review the current understanding of COVID-19 acute respiratory disease and summarize its clinical features with their prospective control and various aspects of the therapeutic approach.