Pterodontic Acid Isolated from Laggera pterodonta Inhibits Viral Replication and Inflammation Induced by Influenza A Virus

Investigating the effects of Laggera pterodonta on H3N2-Induced inflammatory and immune responses through network pharmacology, molecular docking, and experimental validation in a mice model

For centuries, Laggera pterodonta (LP), a Chinese herbal medicine, has been widely employed for treating respiratory infectious diseases; however, the mechanism underlying LP's effectiveness against the influenza A/Aichi/2/1968 virus (H3N2) remains elusive. This study aims to shed light on the mechanism by which LP combats influenza in H3N2-infected mice. First, we conducted quasi-targeted metabolomics analysis using liquid chromatography-mass spectrometry to identify LP components. Subsequently, network pharmacology, molecular docking, and simulation were conducted to screen candidate targets associated with AKT and NF-κB. In addition, we conducted a series of experiments including qPCR, hematoxylin-eosin staining, flow cytometry, immunohistochemistry, and enzyme-linked immunosorbent assay to provide evidence that LP treatment in H3N2-infected mice can reduce pro-inflammatory cytokine levels (TNF-α, IL-6, IL-1β, and MCP-1) while increasing T cells (CD3+, CD4+, and CD8+) and syndecan-1 and secretory IgA expression. This, in turn, aids in the prevention of excessive inflammation and the fortification of immunity, both of which are compromised by H3N2. Finally, we utilized a Western blot assay to confirm that LP indeed inhibits the AKT/NF-κB signaling cascade. Thus, the efficacy of LP serves as a cornerstone in establishing a theoretical foundation for influenza treatment.

Discovery of the covalent SARS-CoV-2 Mpro inhibitors from antiviral herbs via integrating target-based high-throughput screening and chemoproteomic approaches

The main proteases (Mpro ) are highly conserved cysteine-rich proteins that can be covalently modified by numerous natural and synthetic compounds. Herein, we constructed an integrative approach to efficiently discover covalent inhibitors of Mpro from complex herbal matrices. This work begins with biological screening of 60 clinically used antiviral herbal medicines, among which Lonicera japonica Flos (LJF) demonstrated the strongest anti-Mpro effect (IC50  = 37.82 μg/mL). Mass spectrometry (MS)-based chemical analysis and chemoproteomic profiling revealed that LJF extract contains at least 50 constituents, of which 22 exhibited the capability to covalently modify Mpro . We subsequently verified the anti-Mpro effects of these covalent binders. Gallic acid and quercetin were found to potently inhibit severe acute respiratory syndrome coronavirus 2 Mpro in dose- and time- dependent manners, with the IC50 values below 10 µM. The inactivation kinetics, binding affinity and binding mode of gallic acid and quercetin were further characterized by fluorescence resonance energy transfer, surface plasmon resonance, and covalent docking simulations. Overall, this study established a practical approach for efficiently discovering the covalent inhibitors of Mpro from herbal medicines by integrating target-based high-throughput screening and MS-based assays, which would greatly facilitate the discovery of key antiviral constituents from medicinal plants.

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.

Research progress on the effect of traditional Chinese medicine on the activation of PRRs-mediated NF-κB signaling pathway to inhibit influenza pneumonia

Influenza pneumonia has challenged public health and social development. One of the hallmarks of severe influenza pneumonia is overproduction of pro-inflammatory cytokines and chemokines, which result from the continuous activation of intracellular signaling pathways, such as the NF-κB pathway, mediated by the interplay between viruses and host pattern recognition receptors (PRRs). It has been reported that traditional Chinese medicines (TCMs) can not only inhibit viral replication and inflammatory responses but also affect the expression of key components of PRRs and NF-κB signaling pathways. However, whether the antiviral and anti-inflammatory roles of TCM are related with its effects on NF-κB signaling pathway activated by PRRs remains unclear. Here, we reviewed the mechanism of PRRs-mediated activation of NF-κB signaling pathway following influenza virus infection and summarized the influence of anti-influenza TCMs on inflammatory responses and the PRRs/NF-κB signaling pathway, so as to provide better understanding of the mode of action of TCMs in the treatment of influenza pneumonia.

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.

Pharmacological Applications and Action Mechanisms of Phytochemicals as Alternatives to Antibiotics in Pig Production

Antibiotics are widely used for infectious diseases and feed additives for animal health and growth. Antibiotic resistant caused by overuse of antibiotics poses a global health threat. It is urgent to choose safe and environment-friendly alternatives to antibiotics to promote the ecological sustainable development of the pig industry. Phytochemicals are characterized by little residue, no resistance, and minimal side effects and have been reported to improve animal health and growth performance in pigs, which may become a promising additive in pig production. This paper summarizes the biological functions of recent studies of phytochemicals on growth performance, metabolism, antioxidative capacity, gut microbiota, intestinal mucosa barrier, antiviral, antimicrobial, immunomodulatory, detoxification of mycotoxins, as well as their action mechanisms in pig production. The review may provide the theoretical basis for the application of phytochemicals functioning as alternative antibiotic additives in the pig industry.

Antiinflammatory phytochemicals against virus-induced hyperinflammatory responses: Scope, rationale, application, and limitations

Uncontrolled inflammatory responses or cytokine storm associated with viral infections results in deleterious consequences such as vascular leakage, severe hemorrhage, shock, immune paralysis, multi-organ failure, and even death. With the emerging new viral infections and lack of effective prophylactic vaccines, evidence-based complementary strategies that limit viral infection-mediated hyperinflammatory responses could be a promising approach to limit host tissue injury. The present review emphasizes the potentials of antiinflammatory phytochemicals in limiting hyperinflammatory injury caused by viral infections. The predominant phytochemicals along with their mechanism in limiting hyperimmune and pro-inflammatory responses under viral infection have been reviewed comprehensively. How certain phytochemicals can be effective in limiting hyper-inflammatory response indirectly by favorably modulating gut microbiota and maintaining a functional intestinal barrier has also been presented. Finally, we have discussed improved systemic bioavailability of phytochemicals, efficient delivery strategies, and safety measures for effective antiinflammatory phytotherapies, in addition to emphasizing the requirement of tightly controlled clinical studies to establish the antiinflammatory efficacy of the phytochemicals. Collectively, the review provides a scooping overview on the potentials of bioactive phytochemicals to mitigate pro-inflammatory injury associated with viral infections.

Phytochemical Profiles and their Anti-inflammatory Responses Against Influenza from Traditional Chinese Medicine or Herbs

Traditional Chinese medicine (TCM) or herbs are widely used in the prevention and treatment of viral infectious diseases. However, the underlying mechanisms of TCMs remain largely obscure due to complicated material basis and multi-target therapeutics. TCMs have been reported to display anti-influenza activity associated with immunoregulatory mechanisms by enhancing host antiinfluenza immune responses. Previous studies have helped us understand the direct harm caused by the virus itself. In this review, we have tried to summarize recent progress in TCM-based anti-influenza research on the indirect harmful immune responses caused by influenza viruses. In particular, the phytochemicals from TCMs responsible for molecular mechanisms of action belonging to different classes, including phenolic compounds, flavonoids, alkaloids and polysaccharides, have been identified and demonstrated. In addition, this review focuses on the pharmacological mechanism, e.g., inflammatory responses and the interferon (IFN) signaling pathway, which can provide a theoretical basis and approaches for TCM based anti-influenza treatment.

Synthesis of pterodontic acid derivatives and the study of their anti-influenza A virus (H1N1) activity

Laggera pterodonta (DC.) Benth, a folk herb widely distributes in southwest China, especially in Yunnan Province, demonstrates anti-pathogenic microorganisms, anti-inflammatory, inhibition of Helicobacter pylori activities in vitro et al. Interestingly, previous studies have shown that pterodontic acid (1), a eudesmane-type sesquiterpene isolated from L. pterodonta (DC.), displays excellent selective antiviral activity to H1N1 subtype of influenza A virus. At the same time, our group also discovered that the antiviral activity of 1 was relatively close to that activity of post-marketed ribavirin. Therefore, we consider that the synthesis of pterodontic acid (1) derivatives and evaluation of their anti-influenza A virus (H1N1) activities is of potential clinical significance. In this manuscript, a series of pterodontic acid derivatives were prepared and demonstrated significantly improved anti-influenza A virus (H1N1) activities, providing more opportunities for the treatment of respiratory viral diseases.

Recent progress in chemical approaches for the development of novel neuraminidase inhibitors

Influenza virus is the main cause of an infectious disease called influenza affecting the respiratory system including the throat, nose and lungs. Neuraminidase inhibitors are reagents used to block the enzyme called neuraminidase to prevent the influenza infection from spreading. Neuraminidase inhibitors are widely used in the treatment of influenza infection, but still there is a need to develop more potent agents for the more effective treatment of influenza. Complications of the influenza disease lead to death, and one of these complications is drug resistance; hence, there is an urgent need to develop more effective agents. This review focuses on the recent advances in chemical synthesis pathways used for the development of new neuraminidase agents along with the medicinal aspects of chemically modified molecules, including the structure-activity relationship, which provides further rational designs of more active small molecules.

Herbal medicine, a reliable support in COVID therapy

At present, specific therapies for COVID-19 are not well established, being certain only that the immune system plays a decisive role in the initiation and progression of the disease. Plants have given and continue to give compounds with great efficiency and low toxicity, some of them being a starting point for extremely effective synthetic substances. Although herbal remedies are used mainly for preventive purposes, there are also guidelines issued by some countries that indicate the use of traditional remedies for different stages of COVID-19 disease.Europe has a long and strong tradition of using medicinal plants for therapeutic purposes, but clinical trials for this type of approach are scarce, compared to Asia. In this regard, a bridge between tradition and science, would have a strong impact on the capacity for prevention and treatment of COVID-19. The paper reviews compounds of plant origin that have previously proven effective in counteracting some coronaviruses but also some of their major effects - direct action on virus replicative apparatus (viral entry or replication, action on the viral enzymatic system), collateral action of natural compounds on the immune system and also the contribution of herbal medicine as vaccine adjuvants are tackled.

Traditional Chinese Medicine in Treating Influenza: From Basic Science to Clinical Applications

Influenza infection is a highly contagious, acute febrile respiratory disease caused by the influenza virus. Traditional Chinese Medicine (TCM) has dominated plenty of theoretical and practical approaches in the treatment of influenza. It is, therefore, important to highlight the effects of TCM in the clinical treatment of influenza and their impact on inhibiting the growth of this virus in laboratory experiments. We scrutinized existing evidence on whether TCM is effective in clinical applications. Moreover, we described the potential mechanisms of TCM against the influenza virus. Our findings provide analytical evidence that supports the effectiveness of TCM in treating influenza infections as well as their mechanisms against this virus.

Morin Hydrate Inhibits Influenza Virus entry into Host Cells and Has Anti-inflammatory Effect in Influenza-infected Mice

Influenza virus is the major cause of seasonal and pandemic flu. Currently, oseltamivir, a potent and selective inhibitor of neuraminidase of influenza A and B viruses, is the drug of choice for treating patients with influenza virus infection. However, recent emergence of oseltamivir-resistant influenza viruses has limited its efficacy. Morin hydrate (3,5,7,2′,4′-pentahydroxyflavone) is a flavonoid isolated from Morus alba L. It has antioxidant, anti-inflammatory, neuroprotective, and anticancer effects partly by the inhibition of the NF-кB signaling pathway. However, its effects on influenza virus have not been studied. We evaluated the antiviral activity of morin hydrate against influenza A/Puerto Rico/8/1934 (A/PR/8; H1N1) and oseltamivir-resistant A/PR/8 influenza viruses in vitro. To determine its mode of action, we carried out time course experiments, and time of addition, hemolysis inhibition, and hemagglutination assays. The effects of the co-administration of morin hydrate and oseltamivir were assessed using the murine model of A/PR/8 infection. We found that morin hydrate reduced hemagglutination by A/PR/8 in vitro. It alleviated the symptoms of A/PR/8-infection, and reduced the levels of pro-inflammatory cytokines and chemokines, such as TNF-α and CCL2, in infected mice. Co-administration of morin hydrate and oseltamivir phosphate reduced the virus titers and attenuated pulmonary inflammation. Our results suggest that morin hydrate exhibits antiviral activity by inhibiting the entry of the virus.

Pterodontic acid isolated from Laggera pterodonta suppressed RIG-I/NF-KB/STAT1/Type I interferon and programmed death-ligand 1/2 activation induced by influenza A virus in vitro

Influenza viruses can bring about acute respiratory diseases and are a potential hazard to human health. Antiviral drugs are the main ways to control the influenza virus infection except the vaccine. In this study, the immune regulation activity of pterodontic acid isolated from Laggera pterodonta induced by influenza A virus in vitro was evaluated. In studies on anti-influenza activity, our results showed that it maybe target the influenza protein of polymerase basic 1 (PB1), polymerase basic 2 (PB2), polymerase acid (PA), nuclear protein (NP), non-structural protein (NS), and matrix protein (M) but not hemagglutinin (HA) and neuraminidase (NA). In studies on immune regulation, our results demonstrated that pterodontic acid can inhibit the Retinoic acid inducible gene-I (RIG-I) expression in mRNA and protein level at 100 μg/ml, then further to clarify its action on the signalling pathway, The results indicated that pterodontic acid can inhibit the Tumor Necrosis Factor-related Apoptosis-inducing Ligand/Fas Ligand (TRAIL/Fasl) expression in mRNA level at 100 μg/ml; the cleaved caspase 3/7, p-NF-KB, and p-ERK were all suppressed in protein level by pterodontic acid at 100 μg/ml. This confirmed its mechanism that restrained the nuclear export of viral RNPs. The interferon system was also affected, the STAT1, IFN-α, IFN-β expression were also inhibited by pterodontic acid at 25-100 μg/ml and also, the important programmed death-ligand of PD-L1 and PD-L2 was inhibited at 50-100 μg/ml. The mechanisms of pterodontic acid against influenza virus infection may be a cascade inhibition and it has the anti-inflammatory activity, which has no side effect, and can be as a supplement drug in clinical influenza virus infection.

Unraveling the Molecular Mechanism of Traditional Chinese Medicine: Formulas Against Acute Airway Viral Infections as Examples

Herbal medicine, including traditional Chinese medicine (TCM), is widely used worldwide. Herbs and TCM formulas contain numerous active molecules. Basically, they are a kind of cocktail therapy. Herb-drug, herb-food, herb-herb, herb-microbiome, and herb-disease interactions are complex. There is potential for both benefit and harm, so only after understanding more of their mechanisms and clinical effects can herbal medicine and TCM be helpful to users. Many pharmacologic studies have been performed to unravel the molecular mechanisms; however, basic and clinical studies of good validity are still not enough to translate experimental results into clinical understanding and to provide tough evidence for better use of herbal medicines. There are still issues regarding the conflicting pharmacologic effects, pharmacokinetics, drug interactions, adverse and clinical effects of herbal medicine and TCM. Understanding study validation, pharmacologic effects, drug interactions, indications and clinical effects, adverse effects and limitations, can all help clinicians in providing adequate suggestions to patients. At present, it would be better to use herbs and TCM formulas according to their traditional indications matching the disease pathophysiology and their molecular mechanisms. To unravel the molecular mechanisms and understand the benefits and harms of herbal medicine and TCM, there is still much work to be done.

Efficacy and safety of Chou-Ling-Dan granules in the treatment of seasonal influenza via combining Western and traditional Chinese medicine: protocol for a multicentre, randomised controlled clinical trial

INTRODUCTION

Chou-Ling-Dan (CLD) (Laggerapterodonta) granules are an ethnic herbal medicine from Yunnan province of China. CLD granules have been used for the treatment of inflammatory conditions and feverish diseases in China, including seasonal influenza, but few evidence-based medicine (EBM) clinical studies have been conducted to assess its efficacy and safety in the treatment of influenza. Here, we performed an EBM clinical trial combining Western Chinese medicine and traditional Chinese medicine (TCM) evaluation systems to evaluate the efficacy and safety of CLD granules in the treatment of seasonal influenza.

METHODS AND ANALYSIS

The study is designed as a multicentre, randomised, double-blinded, double-simulation, oseltamivir-controlled and placebo-controlled, parallel-design clinical trial. Eligible subjects (n=318) will be allocated after satisfying the criteria (Western medicine). Subjects will be randomised to receive CLD granules, oseltamivir, or a placebo for 5 days of treatment and with follow-up after treatment to record symptoms and signs and to collect pharyngeal/throat swabs and serum samples for detecting the virus and antibodies. At the same time, the syndrome differentiation criteria of TCM, such as tongue body, furred tongue and type of pulse, will be recorded as determined by doctors of both Western and Chinese medicine. Participants will be instructed to comply with the protocol and to keep a daily record of symptoms. The primary and secondary outcomes and safety indicators will be used to evaluate the efficacy and safety of CLD granules in the treatment of seasonal influenza based on both Western Chinese medicine and TCM evaluation systems.

ETHICS AND DISSEMINATION

The CLD granules clinical trial will be conducted in accordance with the Declaration of Helsinki and Good Clinical Practice and has been approved by the Ethics Committee of the First Affiliated Hospital of Guangzhou Medical University. All participants must provide written informed consent. The results obtained will be disseminated at international medical conferences and in peer-reviewed publications.

TRIAL REGISTRATION NUMBER

NCT02662426; Pre-results.

(+)‑pinoresinol‑O‑β‑D‑glucopyranoside from Eucommia ulmoides Oliver and its anti‑inflammatory and antiviral effects against influenza A (H1N1) virus infection

Eucommia ulmoides Oliver (Du-Zhong) is an ancient Chinese herbal remedy used for the treatment of various diseases. To date, the effects of its constituent lignans on influenza viruses remain to be elucidated. In the present study, a lignan glycoside was isolated and purified from Eucommia ulmoides Oliver. Its structures were identified via extensive spectroscopic analysis, and its antiviral and anti‑inflammatory activities, specifically against influenza viruses, were determined via a cytopathic effect (CPE) assay, plaque‑reduction assays, a progeny virus yield reduction assay, reverse transcription‑quantitative polymerase chain reaction analysis and a Luminex assay. Additionally, western blot analysis was performed to investigate the underlying mechanisms of its effects against influenza viruses. The chemical and spectroscopic methods determined the structure of lignan glycoside to be (+)‑pinoresinol‑O‑β‑D‑glucopyranoside. The CPE assay showed that (+)‑pinoresinol‑O‑β‑D‑glucopyranoside exerted inhibitory activities with 50% inhibition concentration values of 408.81±5.24 and 176.24±4.41 µg/ml against the influenza A/PR/8/34 (H1N1) and A/Guangzhou/GIRD07/09 (H1N1) strains, respectively. Its antiviral properties were confirmed by plaque reduction and progeny virus yield reduction assays. Additional mechanistic analyses indicated that the anti‑H1N1 virus‑induced effects of (+)‑pinoresinol‑O-β‑D-glucopyranoside were likely due to inactivation of the nuclear factor‑κB, p38 mitogen‑activated protein kinase and AKT signaling pathways. Furthermore, (+)‑pinoresinol‑O‑β‑D‑glucopyranoside exhibited pronounced inhibitory effects on the expression of influenza H1N1 virus‑induced pro‑inflammatory mediators, including tumor necrosis factor‑α, interleukin (IL)‑6, IL‑8 and monocyte chemoattractant protein 1. The data obtained suggest that (+)‑pinoresinol‑O‑β‑D-glucopyranoside may be a candidate drug for treating influenza H1N1 virus infection.