Development of anti‐influenza agents from natural products

Citrus-derived flavanones as neuraminidase inhibitors: In vitro and in silico study

Neuraminidase (NA) has been well-studied as a therapeutic target for Influenza. However, resistance to the influenza virus has been observed recently. Out of special interest in the utilization of dietary antivirals from citrus, in vitro inhibition activity against NA and in silico studies including molecular docking, molecular dynamic simulation, and a predictive ADMET study, were performed on five citrus-derived flavanones. Encouragingly, citrus-derived flavanones displayed comparable or even more potent in vitro inhibitory activity than oseltamivir carboxylate against NA. Orange peel extract exhibited higher activity than hesperidin. Among the tested compounds, neohesperidin, forming strong hydrogen-bonding interactions with key arginine residues, exhibited the most effective inhibitory activity against NAs from C. perfringens, consistent with the results of molecular dynamics simulations. Although the molecular docking results were inconsistent with the in vitro activity, the binding energy was identical against the wild-type and mutant, suggesting a lower likelihood of developing drug resistance. Moreover, predictive ADMET studies showed favorable pharmacokinetic properties for the tested compounds. Overall, citrus fruit peel emerges as a promising dietary supplement for prevention and treatment of influenza. These findings elucidate the impact of flavanones on NA activity, and the analysis of their binding modes provides valuable insights into the mechanism of NA inhibition.

Fei-Yan-Qing-Hua decoction attenuates influenza virus infection by enhancing host antiviral response through microbiota-derived acetate

Background

Fei-Yan-Qing-Hua decoction (FYQHD) is derived from the well-known Ma Xing Shi Gan decoction, which was documented in Zhang Zhong Jing's "Treatise on Exogenous Febrile Disease" during the Han Dynasty. Although FYQHD has been used in the treatment of pneumonia and has demonstrated clinical efficacy for decades, the underlying mechanism by which FYQHD protects against influenza virus infection through modulation of gut flora remains unclear. Here, we examined the regulatory impacts of FYQHD on an influenza virus-infected mouse model and explored the mechanisms involved.

Methods

An infectious mouse model was created by intranasal instillation of influenza A virus (IAV). The effectiveness of FYQHD was assessed through various measures, including weight loss, lung wet/dry ratio, oxidative stress levels, viral load in lung tissues, and intestinal injuries. Changes in gut microbiota and SCFA production were also examined.

Results

The results showed that FYQHD significantly reduced viral load, increased the production of type I interferon (IFN-I), and restored the integrity of the intestinal barrier following IAV challenge. Additionally, FYQHD significantly corrected the dysbiosis of gut microbiota induced by influenza virus infection, enhancing the abundance of SCFA-producing bacteria and acetate production. However, the depletion of gut microbiota significantly attenuated the protective effects of FYQHD against influenza virus infection. In vitro, the antiviral effect of acetate was demonstrated through the upregulation of concentrations of IFN-β.

Conclusion

FYQHD attenuates influenza virus-induced lung and intestinal injuries by boosting the host antiviral response through increasing the abundance of Lachnospiraceae_NK4A136 and Roseburia, along with elevated acetate levels. The study advances our understanding of the therapeutic mechanisms of FYQHD and provides a theoretical basis for the application of FYQHD in the treatment of influenza.

Geniposide attenuates influenza virus-induced pneumonia by regulating inflammatory cytokines production. Evidences to elucidate the followed pathway

BACKGROUND

Influenza virus-induced pneumonia (IVP) is an infectious pulmonary disease characterized by exacerbated pulmonary inflammation caused by invasion of the influenza virus. IVP continues to threaten public health due to its high morbidity and mortality rates. Geniposide is one of the major bioactive constituents of G. jasminoides, which exerts antiviral and anti-inflammatory effects on influenza A virus (IAV) infection.

PURPOSE

To investigate therapeutic effects and comprehensive mechanisms of geniposide on IAV infection and subsequent pneumonia.

METHODS

ICR mice were infected intranasally with H1N1 (A/FM/1/47) to detect the anti-IAV activity of geniposide. Proteomics combined with function-integrated analysis were conducted to gain insight into the comprehensive mechanisms of geniposide. Subsequently, western blot was used to detect the phosphorylation of signal transducer and activator of transcription 1 (STAT1), signal transducer and activator of transcription 2 (STAT2), Interferon regulatory factor 9 (IRF9) and Janus kinase 1 (JAK1) in Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway in lung tissue. Finally, RT-qPCR was used to detect the levels of interleukin 6 (IL-6), interleukin 17 (IL-17), interferon-γ (IFN-γ) and the STAT1 inhibitor (fludarabine) was used to verify the targeting between STAT1 and geniposide in RAW cells.

RESULTS

Geniposide could significantly reduce the lung index, diminish lung pathology, decrease the virus loads and the inflammatory cytokines expression induced by IAV infection. A total of 411 differentially expressed proteins were identified among control, model, and geniposide-treated group in proteomic analysis. According to function-integrated analysis, 15 KEGG pathways were enriched and divided into 9 groups (modules), including influenza A, NOD-like receptor signaling, RIG-I-like receptor signaling, and so on. Among these modules, the most intensely interacting module pair was the NOD-like receptor signaling and influenza A, in which STAT1 and STAT2 acted as hubs with critical bridgeness role in the target network of geniposide. This indicated that geniposide may mitigate inflammation and alleviate IVP by JAK/STAT signaling pathways. Moreover, validation experiments confirmed that geniposide can significantly inhibit STAT1 and STAT2 phosphorylation as well as down-regulated expression of IL-6, IFN-γ and IL-17 in lung. Furthermore, when RAW cells were treated with the STAT1 inhibitor (fludarabine), the inhibitory effect of geniposide on IFN-γ and IL-6 was attenuated significantly.

CONCLUSIONS

Geniposide can attenuate IAV-induced pneumonia by regulating inflammatory cytokines production through the JAK/STAT pathway.

Molecular screening of phytocompounds targeting the interface between influenza A NS1 and TRIM25 to enhance host immune responses

BACKGROUND

Influenza A virus causes severe respiratory illnesses, especially in developing nations where most child deaths under 5 occur due to lower respiratory tract infections. The RIG-I protein acts as a sensor for viral dsRNA, triggering interferon production through K63-linked poly-ubiquitin chains synthesized by TRIM25. However, the influenza A virus's NS1 protein hinders this process by binding to TRIM25, disrupting its association with RIG-I and preventing downstream interferon signalling, contributing to the virus's evasion of the immune response.

METHODS

In our study we used structural-based drug designing, molecular simulation, and binding free energy approaches to identify the potent phytocompounds from various natural product databases (>100,000 compounds) able to inhibit the binding of NS1 with the TRIM25.

RESULTS

The molecular screening identified EA-8411902 and EA-19951545 from East African Natural Products Database, NA-390261 and NA-71 from North African Natural Products Database, SA-65230 and SA- 4477104 from South African Natural Compounds Database, NEA- 361 and NEA- 4524784 from North-East African Natural Products Database, TCM-4444713 and TCM-6056 from Traditional Chinese Medicines Database as top hits. The molecular docking and binding free energies results revealed that these compounds have high affinity with the specific active site residues (Leu95, Ser99, and Tyr89) involved in the interaction with TRIM25. Additionally, analysis of structural dynamics, binding free energy, and dissociation constants demonstrates a notably stronger binding affinity of these compounds with the NS1 protein. Moreover, all selected compounds exhibit exceptional ADMET properties, including high water solubility, gastrointestinal absorption, and an absence of hepatotoxicity, while adhering to Lipinski's rule.

CONCLUSION

Our molecular simulation findings highlight that the identified compounds demonstrate high affinity for specific active site residues involved in the NS1-TRIM25 interaction, exhibit exceptional ADMET properties, and adhere to drug-likeness criteria, thus presenting promising candidates for further development as antiviral agents against influenza A virus infections.

Fuzhengjiedu San inhibits porcine reproductive and respiratory syndrome virus by activating the PI3K/AKT pathway

BACKGROUND

Traditional Chinese medicine (TCM) has been garnering ever-increasing worldwide attention as the herbal extracts and formulas prove to have potency against disease. Fuzhengjiedu San (FZJDS), has been extensively used to treat viral diseases in pigs, but its bioactive components and therapeutic mechanisms remain unclear.

METHODS

In this study, we conducted an integrative approach of network pharmacology and experimental study to elucidate the mechanisms underlying FZJDS's action in treating porcine reproductive and respiratory syndrome virus (PRRSV). We constructed PPI network and screened the core targets according to their degree of value. GO and KEGG enrichment analyses were also carried out to identify relevant pathways. Lastly, qRT-PCR, flow cytometry and western blotting were used to determine the effects of FZJDS on core gene expression in PRRSV-infected monkey kidney (MARC-145) cells to further expand the results of network pharmacological analysis.

RESULTS

Network pharmacology data revealed that quercetin, kaempferol, and luteolin were the main active compounds of FZJDS. The phosphatidylinositol-3-kinase (PI3K)/Akt pathway was deemed the cellular target as it has been shown to participate most in PRRSV replication and other PRRSV-related functions. Analysis by qRT-PCR and western blotting demonstrated that FZJDS significantly reduced the expression of P65, JNK, TLR4, N protein, Bax and IĸBa in MARC-145 cells, and increased the expression of Bcl-2, consistent with network pharmacology results. This study provides that FZJDS has significant antiviral activity through its effects on the PI3K/AKT signaling pathway.

CONCLUSION

We conclude that FZJDS is a promising candidate herbal formulation for treating PRRSV and deserves further investigation.

Synthesis and pharmacodynamic evaluation of naphthalene derivatives against influenza A virus in vitro and in vivo

Influenza A virus is a highly mutable pathogenic pathogen that could cause a global pandemic. It is necessary to find new anti-influenza drugs to resist influenza epidemics due to the seasonal popularity of a certain area every year. Naphthalene derivatives had potential antiviral activity. A series of naphthalene derivatives were synthesized via the metal-free intramolecular hydroarylation reactions of alkynes. Evaluation of their biological efficacy showed that compound 2-aminonaphthalene 4d had better antiviral activity in vitro than ribavirin. By studying the mechanism of action of 2-aminonaphthalene 4din vivo and in vitro, we found that 4d had antiviral activity to three different subtype influenza viruses of A/Weiss/43 (H1N1), A/Virginia/ATCC2/2009 (H1N1) and A/California/2/2014 (H3N2). Compound 4d had the best effect after viral adsorption, and mainly played in the early stage of virus replication. 2-Aminonaphthalene 4d could reduce the replication of virus by inhibiting the NP and M proteins of virus. Compound 4d cut down ROS accumulation, autophagy and apoptosis induced by influenza virus. Inflammatory response mediated by RIG-1 pathway were suppressed in the cell and mice. In addition, the pathological changes of lung tissue and virus titer in mice were reduced by the administration of 4d. Therefore, naphthalene derivative 4d is a potential drug for the treatment of influenza A virus infection.

Interplay of Modified Sialic Acid Inhibitors and the Human Parainfluenza Virus 1 Hemagglutinin-Neuraminidase Active Site

In the search for effective antivirals against Paramyxoviridae, the dynamics of human parainfluenza virus type 1 hemagglutinin-neuraminidase (hPIV1-HN) inhibition offers a promising perspective. This study focuses on the potential of C5- and C4-modified 2,3-unsaturated sialic acid (DANA) inhibitors and highlights their interaction with the hPIV1-HN enzyme. We show that a strategic substitution, replacing the C5 isopropyl group in BCX 2798 with a trifluoroacetyl function, increases inhibitory potency 3- to 4-fold. At the same time, we explore the special properties of the catalytic site of hPIV1-HN, which harbors only small substituents and favors a C4 sulfonylamido function over a carbonyl function, in contrast to the C4 pocket of Newcastle disease virus hemagglutinin-neuraminidase (NDV-HN). Based on these findings, we present a newly identified potent inhibitor that has the preferred C5 trifluoroacetamido and C4 trifluorosulfonylamide groups. The results of this study pave the way for a deeper understanding of the C4 and C5 binding pockets of hPIV1-HN and promote the development of new, more selective inhibitors.

Secondary Metabolites, Biological Activities, and Industrial and Biotechnological Importance of Aspergillus sydowii

Marine-derived fungi are renowned as a source of astonishingly significant and synthetically appealing metabolites that are proven as new lead chemicals for chemical, pharmaceutical, and agricultural fields. Aspergillus sydowii is a saprotrophic, ubiquitous, and halophilic fungus that is commonly found in different marine ecosystems. This fungus can cause aspergillosis in sea fan corals leading to sea fan mortality with subsequent changes in coral community structure. Interestingly, A. sydowi is a prolific source of distinct and structurally varied metabolites such as alkaloids, xanthones, terpenes, anthraquinones, sterols, diphenyl ethers, pyrones, cyclopentenones, and polyketides with a range of bioactivities. A. sydowii has capacity to produce various enzymes with marked industrial and biotechnological potential, including α-amylases, lipases, xylanases, cellulases, keratinases, and tannases. Also, this fungus has the capacity for bioremediation as well as the biocatalysis of various chemical reactions. The current work aimed at focusing on the bright side of this fungus. In this review, published studies on isolated metabolites from A. sydowii, including their structures, biological functions, and biosynthesis, as well as the biotechnological and industrial significance of this fungus, were highlighted. More than 245 compounds were described in the current review with 134 references published within the period from 1975 to June 2023.

Design, Synthesis, and Antiviral Evaluation of Sialic Acid Derivatives as Inhibitors of Newcastle Disease Virus Hemagglutinin-Neuraminidase: A Translational Study on Human Parainfluenza Viruses

Global infections with viruses belonging to the Paramyxoviridae, such as Newcastle disease virus (NDV) or human parainfluenza viruses (hPIVs), pose a serious threat to animal and human health. NDV-HN and hPIVs-HN (HN hemagglutinin-neuraminidase) share a high degree of similarity in catalytic site structures; therefore, the development of an efficient experimental NDV host model (chicken) may be informative for evaluating the efficacy of hPIVs-HN inhibitors. As part of the broad research in pursuit of this goal and as an extension of our published work on antiviral drug development, we report here the biological results obtained with some newly synthesized C4- and C5-substituted 2,3-unsaturated sialic acid derivatives against NDV. All developed compounds showed high neuraminidase inhibitory activity (IC₅₀ 0.03-13 μM). Four molecules (9, 10, 23, 24) confirmed their high in vitro inhibitory activity, which caused a significant reduction of NDV infection in Vero cells, accompanied by very low toxicity.

New insights for infection mechanism and potential targets of COVID-19: Three Chinese patent medicines and three Chinese medicine formulas as promising therapeutic approaches

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with high pathogenicity and infectiousness has become a sudden and lethal pandemic worldwide. Currently, there is no accepted specific drug for COVID-19 treatment. Therefore, it is extremely urgent to clarify the pathogenic mechanism and develop effective therapies for patients with COVID-19. According to several reliable reports from China, traditional Chinese medicine (TCM), especially for three Chinese patent medicines and three Chinese medicine formulas, has been demonstrated to effectively alleviate the symptoms of COVID-19 either used alone or in combination with Western medicines. In this review, we systematically summarized and analyzed the pathogenesis of COVID-19, the detailed clinical practice, active ingredients investigation, network pharmacology prediction and underlying mechanism verification of three Chinese patent medicines and three Chinese medicine formulas in the COVID-19 combat. Additionally, we summarized some promising and high-frequency drugs of these prescriptions and discussed their regulatory mechanism, which provides guidance for the development of new drugs against COVID-19. Collectively, by addressing critical challenges, for example, unclear targets and complicated active ingredients of these medicines and formulas, we believe that TCM will represent promising and efficient strategies for curing COVID-19 and related pandemics.

Qingfei Jiedu Granules fight influenza by regulating inflammation, immunity, metabolism, and gut microbiota

Background and aim

Qingfei Jiedu Granules (QFJD) are a new Traditional Chinese Medicine (TCM) which has been clinically used against coronavirus pneumonia in China. In this study, the therapeutic effect and the underlying mechanisms of QFJD against influenza were investigated.

Experimental procedure

Pneumonia mice were induced by influenza A virus. Survival rate, weight loss, lung index and lung pathology were measured to evaluate the therapeutic effect of QFJD. The expression of inflammatory factors and lymphocytes was used to assess anti-inflammatory and immunomodulatory effect of QFJD. Gut microbiome analysis was performed to decipher the potential effect of QFJD on intestinal microbiota. Metabolomics approach was conducted to explore the overall metabolic regulation of QFJD.

Result and conclusion

QFJD shows a significant therapeutic effect on the treatment of influenza and the expression of many pro-inflammatory cytokines were obviously inhibited. QFJD also markedly modulates the level of T and B lymphocytes. The high-dose QFJD has shown similar therapeutic efficiency compared to positive drugs. QFJD profoundly enriched Verrucomicrobia and maintained the balance between Bacteroides and Firmicutes. QFJD associated with 12 signaling pathways in metabolomics study, 9 of which were the same as the model group and were closely related to citrate cycle and amino acid metabolism.To sum up, QFJD is a novel and promising drug against influenza. It can regulate inflammation, immunity, metabolism, and gut microbiota to fight influenza. Verrucomicrobia shows great potential to improve influenza infection and may be an important target.

Quinones as Promising Compounds against Respiratory Viruses: A Review

Respiratory viruses represent a world public health problem, giving rise to annual seasonal epidemics and several pandemics caused by some of these viruses, including the COVID-19 pandemic caused by the novel SARS-CoV-2, which continues to date. Some antiviral drugs have been licensed for the treatment of influenza, but they cause side effects and lead to resistant viral strains. Likewise, aerosolized ribavirin is the only drug approved for the therapy of infections by the respiratory syncytial virus, but it possesses various limitations. On the other hand, no specific drugs are licensed to treat other viral respiratory diseases. In this sense, natural products and their derivatives have appeared as promising alternatives in searching for new compounds with antiviral activity. Besides their chemical properties, quinones have demonstrated interesting biological activities, including activity against respiratory viruses. This review summarizes the activity against respiratory viruses and their molecular targets by the different types of quinones (both natural and synthetic). Thus, the present work offers a general overview of the importance of quinones as an option for the future pharmacological treatment of viral respiratory infections, subject to additional studies that support their effectiveness and safety.

Effectiveness and Safety of Lianhua Qingwen Capsules for COVID-19: A Propensity-Score Matched Cohort Study

As a traditional Chinese medicine, Lianhua Qingwen capsules have been widely used to treat Coronavirus Disease 2019 (COVID-19). This study was aimed to demonstrate the association between treatment with Lianhua Qingwen capsules and the clinical outcomes of hospitalized patients with COVID-19. This retrospective study was conducted at four hospitals in Central China. Data of hospitalized COVID-19 patients were collected between December 19, 2019 and April 26, 2020. Based on whether Lianhua Qingwen capsules were used, patients were classified into Lianhua Qingwen and non-Lianhua Qingwen (control) groups. To control for confounding factors, we used conditional logistic regression in a propensity-score matched (PSM) cohort (1 : 1 balanced), as well as logistic regression without matching as sensitivity analysis. A total of 4918 patients were included, 2760 of whom received Lianhua Qingwen capsules and 2158 of whom did not. In the PSM model, after adjusting for confounders, the in-hospital mortality was similar between the Lianhua Qingwen group and the control group (6.8% vs. 3.3%, adjusted OR, 0.66 [95% CI, 0.38-1.15], p = 0.138). The negative conversion rate of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection was higher in the Lianhua Qingwen group (88.3% vs. 96.1%, adjusted OR, 4.02 [95% CI, 2.58-6.25], p < 0.001). The incidence of acute liver injury was comparable between the two groups (14.0% vs. 11.5%, adjusted OR: 0.85 [95% CI, 0.71-1.02], p = 0.083), and the incidence of acute kidney injury was lower in the Lianhua Qingwen group (5.3% vs. 3.0%, adjusted OR: 0.71 [95% CI, 0.50-1.00], p = 0.048). Treatment with Lianhua Qingwen capsules was not significantly associated with in-hospital mortality in COVID-19 patients. In the Lianhua Qingwen group, the negative conversion rate of SARS-CoV-2 infection was higher and the incidence of acute kidney injury was lower than in the control group.

Proanthocyanidins attenuates ferroptosis against influenza-induced acute lung injury in mice by reducing IFN-γ

BACKGROUND

Acute lung injury (ALI) is associated with high morbidity and mortality and is partly driven promoted by ferroptosis. Proanthocyanidins (PAs) is a natural bioactive flavonoid with anti-inflammatory and antioxidant activities. PAs can also significantly protect against acute lung inflammation and ferroptosis in alveolar epithelial cells. However, it is unclear whether PAs can alleviate ALI by reducing ferroptosis. This study aimed to evaluate the protective effects of PAs and the potential mechanisms against Influenza A virus (IAV)-induced ALI.

METHODS

Mice were inoculated nasally with IAV to induce ALI. IAV-induced pulmonary inflammation and ferroptosis was tested by measuring the levels of malondialdehyde (MDA), glutathione (GSH), glutathione peroxidase 4 (GPX4), solute carrier family 7 member 11 (SLC7A11) and acyl-CoA synthetase long-chain family member (ACSL4) in lung tissue. The potential targets that PAs protect against IAV-induced ALI were determined via a systemic pharmacological analysis. The molecular mechanism of PAs in ALI treatment was investigated by assessing the level of inflammation and ferroptosis markers using Western Blot and quantitative real-time PCR.

RESULTS

Systemic pharmacological analysis suggested that PAs protect against IAV-induced pneumonia thorough TGF-β1 and its relative signaling pathway. PAs effectively alleviated histopathological lung injury, reduced inflammatory cytokines and chemokines secretion, which were increased in IAV-infected mice. Meanwhile, PAs further prevented mouse airway inflammation in ALI, concomitant with the decreased expression TGF-β1, smad2/3, p-Smad2, p-Smad3 and ferroptosis mediator IFN-γ. Furthermore，IFN-γ promotes cell lipid peroxidation and ferroptosis，PAs significantly reduced MDA and ACSL4 levels and upregulated GSH, GPX4, and SLC7A11.

CONCLUSION

Overall, PAs can attenuate ferroptosis against IAV-induced ALI via the TGF-β1/Smad2/3 pathway and is a promising novel therapeutic candidate for ALI.

Rapid screening of neuraminidase inhibitors using an at-line nanofractionation platform involving parallel oseltamivir-sensitive/resistant neuraminidase bioassays

In this study, an advanced at-line nanofractionation based screening platform was developed to screen potential neuraminidase inhibitors (NAIs) from Lonicera japonica Thunb by involving two parallel bioassays, for determining both oseltamivir-sensitive neuraminidase (NAS) and oseltamivir-resistant neuraminidase (NAR) inhibitory activities. 20 potential NAIs with both NAS and NAR inhibitory effects were screened from Lonicera japonica Thunb and identified by mass spectrometer, including 11 phenolic acids, 8 flavonoids and one iridoid glycoside. The proposed at-line nanofractionation based screening platform for NAIs was also used to rapidly screen nine batches of water extracts of Lonicera japonica Thunb or its similar species. Clear differences in the number and content of active components were easily observed, demonstrating that the proposed method possesses great potential for the quality control of herb medicines.

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

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

Research progress on antiviral constituents in traditional Chinese medicines and their mechanisms of action

CONTEXT

Viruses have the characteristics of rapid transmission and high mortality. At present, western medicines still lack an ideal antiviral. As natural products, many traditional Chinese medicines (TCM) have certain inhibitory effects on viruses, which has become the hotspot of medical research in recent years.

OBJECTIVE

The antiviral active ingredients and mechanisms of TCM against viral diseases was studied in combination with the pathogenesis of viral diseases and antiviral effects.

MATERIALS AND METHODS

English and Chinese literature from 1999 to 2021 was collected from databases including Web of Science, PubMed, Elsevier, Chinese Pharmacopoeia 2020 (CP), and CNKI (Chinese). Traditional Chinese medicines (TCM), active ingredients, antiviral, mechanism of action, and anti-inflammatory effect were used as the key words.

RESULTS

The antiviral activity of TCM is clarified to put forward a strategy for discovering active compounds against viruses, and provide reference for screening antivirus drugs from TCM. TCM can not only directly kill viruses and inhibit the proliferation of viruses in cells, but also prevent viruses from infecting cells and causing cytophilia. It can also regulate the human immune system, enhance human immunity, and play an indirect antiviral role.

DISCUSSION AND CONCLUSION

Based on the experimental study and antiviral mechanism of TCM, this paper can provide analytical evidence that supports the effectiveness of TCM in treating virus infections, as well as their mechanisms against viruses. It could be helpful to provide reference for the research and development of innovative TCMs with multiple components, multiple targets and low toxicity.

Lead/Drug Discovery from Natural Resources

Natural products and their derivatives have been shown to be effective drug candidates against various diseases for many years. Over a long period of time, nature has produced an abundant and prosperous source pool for novel therapeutic agents with distinctive structures. Major natural-product-based drugs approved for clinical use include anti-infectives and anticancer agents. This paper will review some natural-product-related potent anticancer, anti-HIV, antibacterial and antimalarial drugs or lead compounds mainly discovered from 2016 to 2022. Structurally typical marine bioactive products are also included. Molecular modeling, machine learning, bioinformatics and other computer-assisted techniques that are very important in narrowing down bioactive core structural scaffolds and helping to design new structures to fight against key disease-associated molecular targets based on available natural products are considered and briefly reviewed.

Antiviral Potential of Natural Resources against Influenza Virus Infections

Influenza is a severe contagious disease caused by influenza A and B viruses. The WHO estimates that annual outbreaks lead to 3-5 million severe infections of which approximately 10% lead to the death of the patient. While vaccination is the cornerstone of prevention, antiviral drugs represent the most important treatment option of acute infections. Only two classes of drugs are currently approved for the treatment of influenza in numerous countries: M2 channel blockers and neuraminidase inhibitors. In some countries, additional compounds such as the recently developed cap-dependent endonuclease inhibitor baloxavir marboxil or the polymerase inhibitor favipiravir are available. However, many of these compounds suffer from poor efficacy, if not applied early after infection. Furthermore, many influenza strains have developed resistances and lost susceptibility to these compounds. As a result, there is an urgent need to develop new anti-influenza drugs against a broad spectrum of subtypes. Natural products have made an important contribution to the development of new lead structures, particularly in the field of infectious diseases. Therefore, this article aims to review the research on the identification of novel lead structures isolated from natural resources suitable to treat influenza infections.

Discovery of Cyclic Diarylheptanoids as Inhibitors against Influenza A Virus from the Roots of Casuarina equisetifolia

Four new cyclic diarylheptanoids, casuarinols A-C (1-3) and casuarinolide A (4), together with six known ones (5-10), were isolated from the roots of Casuarina equisetifolia. Structures were elucidated by extensive spectroscopic analysis, theoretical conformational, and electronic circular dichroism analyses. Casuarinol C (3) is a novel cyclic diarylheptanoid-aldehyde adduct. Casuarinolide A (4) represents the first structure of a seco-cyclic diarylheptanoid. Compounds 1-9 were evaluated for their anti-influenza A virus (IAV) activity against A/WSN/33 (H1N1). (-)-(M)-11-Oxo-3,12R,17-trihydroxy-9-ene-[7,0]-metacyclophane (5) displayed significant anti-IAV activity with an IC₅₀ value of 8.64 ± 2.49 μM and a CC₅₀ higher than 100 μM.

Organic Acid Analysis in Green Tea Leaves Using High-performance Liquid Chromatography

Green tea is a popular refreshing drink with several functional properties attributed to its bioactive compounds. The bioactive content and composition vary with several factors. Several advances in chromatographic studies have facilitated the study of chemical composition of green tea leaves; however, the content of organic acids, particularly quinic acid, has not been explored fully. Therefore, changes in the content of organic acids, including quinic acid, in green tea leaves, were investigated in this study. All the studied varieties contained large amounts of quinic and oxalic acids. Kukicha and Matcha contained the highest and lowest amounts of quinic acid, respectively. Furthermore, high-grade Matcha had a significantly lower quinic acid content than low-grade Matcha. The Asatsuyu sample had the lowest quinic acid content in 2018 and 2019 compared with the other green tea varieties. The content of quinic acid increased with maturity, but that of oxalic, malic, succinic, and citric acids decreased after a slight increase. Shading cultivation in Saeakari significantly lowered the quinic acid content and slightly increased the content of malic, citric, and oxalic acids. Malic acid and citric acid content in Yabukita changed with sunrise and sunset, but that of other organic acids did not show any considerable change. These results show that using an appropriate plucking time could lead to further improvement in the quality of green tea leaves. Overall, green tea is a good source of quinic acid, which will attract attention in future functional research on this drink.

Traditional Chinese Medicine Injections Combined With Oseltamivir for Influenza: Systematic Review and Network Meta-Analysis

Background: As a cause of respiratory tract infections in humans, influenza remains with high morbidity and mortality, with associated significant healthcare burden and increased financial burden. Traditional Chinese medicine injections (TCMIs) combined with oseltamivir (TCMIs + oseltamivir) are the representative therapeutic strategies for influenza, which is a compliant with clinical applications in China. The aim of this study was to describe the comparative efficacy and safety of TCMIs + oseltamivir in patients with influenza, based on the current evidence.

Methods: PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform, VIP information resource integration service platform databases, and the Chinese biomedical literature service system were searched to find randomized controlled trials where TCMIs + oseltamivir are the representative therapeutic strategies for influenza, from inception until October 2021, without language restriction. Two investigators independently screened eligibility criteria, extracted data, and appraised the risk of bias with the same criteria. We conducted a network meta-analysis using the Bayesian random method for each outcome and performed the sensitivity analysis, meta-regression, and Egger’s and Begg’s tests for the reliability and robustness of our results.

Results: Thirty-one trials including 2,893 participants proved eligible and reported on four TCMIs + oseltamivir versus oseltamivir. Network meta-analysis showed Yanhuning (YHN) +oseltamivir (MD = −1.7, 95% CrI: −2.5 to −0.88; SUCRA = 0.89; low certainty of evidence) in fever disappearance time, Tanreqing (TRQ) +oseltamivir (MD = −1.9, 95% CrI: −2.8 to −1; SUCRA = 0.97; low certainty of evidence) in cough disappearance time, and Xiyanping (XYP) +oseltamivir (OR = 5.9, 95% CrI: 3.1 to 11; SUCRA = 0.82; very low certainty of evidence) in the response rate to be more efficacious than oseltamivir alone with the best SUCRA. Based on the combined SUCRA value for primary outcomes, TRQ + oseltamivir is probably better in cough disappearance time, and XYP + oseltamivir and YHN + oseltamivir may be better in fever disappearance time than others. No significant difference in safety between the treatments.

Conclusion: In patients with influenza, TCMIs + oseltamivir only partially improve flu symptoms. Overall therapeutic efficacy and safety are inconclusive, based on low to very low certainty of evidence. However, the safety remains uncertain, and TCMI treatments for influenza should be considered with caution. More high-quality studies examining the efficacy and safety of TCMIs are needed.

Systematic Review Registration:https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42021286994

The efficacy and safety of combined chinese herbal medicine and western medicine therapy for COVID-19: a systematic review and meta-analysis

OBJECTIVE

To systematically review the clinical efficacy and safety of Chinese herbal medicine (CHM) with and without Western medicine (WM) for different severity of COVID-19.

METHODS

CNKI, PubMed, Wanfang Database, ClinicalTrails.gov, Embase, ChiCTR and ICTRP were searched from 01 Jan, 2020 to 30 Jun, 2021. Two authors independently assessed all the randomized clinical trials (RCTs) for trial inclusion, data extraction and quality assessment. Meta-analysis was conducted using Review Manager software (RevMan 5.4.1). Evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Primary outcomes included total effectiveness rate. Secondary outcomes included improvements in symptom improvement and total adverse event rate. Different severity of COVID-19 patients was assessed in subgroup analysis. This study was registered with INPLASY, INPLASY202210072.

RESULTS

22 high quality RCTs involving 1789 participants were included. There were no trial used CHM alone nor compare placebo or no treatment. Compared with WM, combined CHM and WM (CHM-WM) treatment showed higher total effectiveness rate, lower symptom scores of fever, cough, fatigue, dry throat and pharyngalgia, shorter mean time to viral conversion, better Computerized Tomography (CT) image and blood results, fewer total adverse events and worse conditions (P < 0.05). Subgroup analysis showed that the total effectiveness rate of combined CHM-WM group was significantly higher than WM group, especially for mild and moderate patients. No significant differences in mortality and adverse events were found between combined CHM-WM and WM treatment. No serious adverse events and long-term outcomes were reported.

CONCLUSION

Current evidence supported the therapeutic effects and safety of combined CHM-WM treatment on COVID-19, especially for patients with mild and moderate symptoms. Long-term effects of therapy are worthy in further study.

Adenosine and L-proline can possibly hinder Chinese Sacbrood virus infection in honey bees via immune modulation

Sacbrood virus (SBV) infects larvae of honey bees, resulting in infected larvae becoming fluid-filled sacs. Our previous studies showed that the extract of herbal medicine, Radix Isatidis, could inhibit Chinese SBV (CSBV) infection in Asian honey bees (Apis cerana). Here, two compounds, adenosine and L-proline, which were previously reported to be associated with immune modulation, were identified in R. Isatidis extract and then selected for an evaluation of their antiviral effect on CSBV infection in A. cerana. Our results revealed that both adenosine and L-proline could significantly mitigate the impact of CSBV on the growth and development of infected larvae and modulate hosts' immune responses by downregulating the expression of immune genes in infected larvae. The results gained from this study suggest that adenosine and L-proline could possibly interfere CSBV infection via immune modulation to avoid exacerbations and nonspecific damage to infected larvae's own tissues.

(-)-Lariciresinol Isolated from the Roots of Isatis indigotica Fortune ex Lindl. Inhibits Hepatitis B Virus by Regulating Viral Transcription

Chronic hepatitis induced by hepatitis B virus (HBV) infection is a serious public health problem, leading to hepatic cirrhosis and liver cancer. Although the currently approved medications can reliably decrease the virus load and prevent the development of hepatic diseases, they fail to induce durable off-drug control of HBV replication in the majority of patients. The roots of Isatis indigotica Fortune ex Lindl., a traditional Chinese medicine, were frequently used for the prevention of viral disease in China. In the present study, (-)-lariciresinol ((-)-LRSL), isolated from the roots of Isatis indigotica Fortune ex Lindl., was found to inhibit HBV DNA replication of both wild-type and nucleos(t)ide analogues (NUCs)-resistant strains in vitro. Mechanism studies revealed that (-)-LRSL could block RNA production after treatment, followed by viral proteins, and then viral particles and DNA. Promoter reporter assays and RNA decaying dynamic experiments indicated that (-)-LRSL mediated HBV RNA reduction was mainly due to transcriptional inhibition rather than degradation. Moreover, (-)-LRSL in a dose-dependent manner also inhibited other animal hepadnaviruses, including woodchuck hepatitis virus (WHV) and duck hepatitis B virus (DHBV). Combining the analysis of RNA-seq, we further found that the decrease in HBV transcriptional activity by (-)-LRSL may be related to hepatocyte nuclear factor 1α (HNF1α). Taken together, (-)-LRSL represents a novel chemical entity that inhibits HBV replication by regulating HNF1α mediated HBV transcription, which may provide a new perspective for HBV therapeutics.

Trillin inhibits myoblast differentiation via increasing autophagy

BACKGROUND

Trillin, an active ingredient in traditional Chinese medicine Trillium tschonoskii, is a potential small molecule compound candidate that affecting myoblast differentiation, which predicting by AI technology in our previous study. Autophagy modulating myoblast differentiation has also been studied. In addition, Trillin was shown to regulate mTOR signaling pathway, a highly conserved kinase important for autophagy regulation.

PURPOSE

In this research, we aim to clarify the effect and underlying mechanism of Trillin on myoblast differentiation.

STUDY DESIGN AND METHODS

Using mice C2C12 cell line to establish a myoblast differentiation model in vitro, treated with different concentration and time of Trillin, to explore the effect and latent mechanism of Trillin on myoblast differentiation by qRT-PCR, Western Blot and other molecular biological technique.

RESULTS

Results showed that C2C12 differentiation was significantly inhibited by Trillin in a dose-dependent manner. The expression of MyHC, MyOG and MyoD was decreased extremely significant after 10 μM Trillin treatment. Meanwhile, autophagy level was significantly elevated with the supplement of Trillin. And C2C12 differentiation was recovered after ATG7 knockdown. Mechanically, we found that the activity of AKT/mTOR declined during the inhibition of differentiation by Trillin.

CONCLUSION

Our findings suggested that Trillin attenuated C2C12 differentiation via increasing autophagy through AKT/mTOR signaling pathway. Taken together, we introduce a novel physiological function of Trillin in inhibiting skeletal muscle differentiation.

Clinical Efficacy and Safety of Chinese Patent Medicine Combined with Oseltamivir for the Treatment of Adult Influenza: A Systematic Review and Meta-Analysis

Influenza is a sudden and serious viral breathing and lung-related infectious disease that causes significant deadliness and death worldwide. Now, the international treatment is oseltamivir. Chinese patent medicine (CPM) as a kind of different therapy is used in the treatment of influenza in China. The aim of this study was to interpret the clinical efficacy and safety of CPM combined with oseltamivir in the treatment of adult influenza by reviewing all relevant randomized controlled trials, and to provide new ideas and methods for the treatment of influenza. PubMed, Embase, Cochrane Library, SinoMed, CNKI, and Wanfang Database were searched from the date of beginning until 1 June 2021, for the references on treatment of influenza with CPM. According to standard information extraction tables, two people worked to find and aggregate information independently. Review Manager 5.2 was used to study data carefully and evaluate risk of bias. A total of nine trials of 906 patients were included. Based on the meta-analysis, compared to oseltamivir, CPM combined with oseltamivir had better effect in the time of defervescence [MD = -17.68, 95% CI (-25.93, -9.44), P < 0.0001], the time of symptom improvement [MD = -22.28, 95% CI (-26.77, -17.80), P < 0.00001], and the time of hospitalization [MD = -2.04, 95% CI (-3.45, -0.63), P = 0.005]. Related to safety [RR = 0.69, 95% CI (0.38, 1.23), P = 0.21], the experimental group had fewer adverse reactions than the control group, but there is no statistical significance. The findings show that CPM combined with oseltamivir in adult influenza has a better efficacy in shortening the time of defervescence and symptom improvement, reducing the time of hospitalization. However, publication bias is inevitable due to the low methodological quality check of the clinical research about diagnostic criteria, definition of adult influenza, and small number of articles, and further large sample sizes and multi-center clinical trials are needed to give better proof for its efficacy and safety.

Isatis indigotica: from (ethno) botany, biochemistry to synthetic biology

Isatis indigotica Fort. (Chinese woad) is a species with an ancient and well-documented history as an indigo dye and medicinal plant. It is often confused with Isatis tinctoria L. (European woad), a medicinal plant in Europe. Here, the differences between I. indigotica and I. tinctoria are systematically described. The usage development history, clinical applications and pharmacological activities, and chemical components of I. indigotica are also summarized. Lignans, indole alkaloids, and their corresponding derivatives have been identified as the major active ingredients of I. indigotica and are associated with anti-viral, anti-inflammatory, anti-cancer, and other health-promoting activities. Notable progress has been made in understanding the biosynthetic pathway and regulation mechanism of lignans and indole alkaloids in I. indigotica, the results from which should facilitate the process of targeted metabolic engineering or synthetic biology. Moreover, multiple biotechnology methods such as polyploid breeding and genetic engineering have been used with I. indigotica to result in, for example, greater yields, higher levels of bioactive component accumulation, and enhanced stress tolerance to salt, drought, and insects. Some issues require additional analyses, and suggestions for future research on I. indigotica are also discussed.

Chinese herbal injections for coronavirus disease 2019 (COVID-19): A narrative review

Background

The outbreak of Coronavirus disease 2019 (COVID-19) has caused more than 180 million infections and 3.9 million deaths. To date, emerging clinical evidence has shown the synergetic benefits of Chinese herbal injections in treating this contagious respiratory disease. This review aims to summarize and analyze the efficacy and safety of Chinese herbal injections in the therapy of COVID-19.

Methods

The literature from 3 electronic databases, PubMed, CNKI, and Web of Science, were searched using the search terms “COVID-19”, “SARS-CoV-2”, “traditional Chinese medicine”, “herb”, “herbal”, and “injection”. Then the identified articles were comprehensively evaluated.

Results

Limited data demonstrated that Chinese herbal injections could significantly improve the clinical outcomes of COVID-19 patients, especially in combination with conventional treatment strategies. The benefits of which were mainly associated with the relief of symptoms, prevention of secondary infection, regulation of inflammation and immune function. There was also evidence showing the inhibitory effects on SARS-CoV-2 replication in vitro. Nevertheless, available real-world data suggested the increased risk of adverse event. Furthermore, the defects of existing researches and the insights for discovering novel antiviral drugs were prospectively discussed.

Conclusion

Evidence-based advances revealed that Chinese herbal injections such as XueBiJing injection and ShenMai injection, exerted potent effects against COVID-19. Further laboratory researches and clinical evaluation are needed to gather scientific evidence on the efficacy and safety.

Integrative analyses of targeted metabolome and transcriptome of Isatidis Radix autotetraploids highlighted key polyploidization-responsive regulators

Background

Isatidis Radix, the root of Isatis indigotica Fort. (Chinese woad) can produce a variety of efficacious compound with medicinal properties. The tetraploid I. indigotica plants exhibit superior phenotypic traits, such as greater yield, higher bioactive compounds accumulation and enhanced stress tolerance. In this study, a comparative transcriptomic and metabolomic study on Isatidis Radix autotetraploid and its progenitor was performed.

Results

Through the targeted metabolic profiling, 283 metabolites were identified in Isatidis Radix, and 70 polyploidization-altered metabolites were obtained. Moreover, the production of lignans was significantly increased post polyploidization, which implied that polyploidization-modulated changes in lignan biosynthesis. Regarding the transcriptomic shift, 2065 differentially expressed genes (DEGs) were identified as being polyploidy-responsive genes, and the polyploidization-altered DEGs were enriched in phenylpropanoid biosynthesis and plant hormone signal transduction. The further integrative analysis of polyploidy-responsive metabolome and transcriptome showed that 1584 DEGs were highly correlated with the 70 polyploidization-altered metabolites, and the transcriptional factors TFs-lignans network highlighted 10 polyploidy-altered TFs and 17 fluctuated phenylpropanoid pathway compounds.

Conclusions

These results collectively indicated that polyploidization contributed to the high content of active compounds in autotetraploid roots, and the gene–lignan pathway network analysis highlighted polyploidy–responsive key functional genes and regulators.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07980-w.

Uncovering Quercetin’s Effects against Influenza A Virus Using Network Pharmacology and Molecular Docking

(1) Background: Re-emerging influenza threats continue to challenge medical and public health systems. Quercetin is a ubiquitous flavonoid found in food and is recognized to possess antioxidant, anti-inflammatory, antiviral, and anticancer activities. (2) Methods: To elucidate the targets and mechanisms underlying the action of quercetin as a therapeutic agent for influenza, network pharmacology and molecular docking were employed. Biological targets of quercetin and target genes associated with influenza were retrieved from public databases. Compound–disease target (C-D) networks were constructed, and targets were further analyzed using KEGG pathway analysis. Potent target genes were retrieved from the compound–disease–pathway (C-D-P) and protein–protein interaction (PPI) networks. The binding affinities between quercetin and the targets were identified using molecular docking. (3) Results: The pathway study revealed that quercetin-associated influenza targets were mainly involved in viral diseases, inflammation-associated pathways, and cancer. Four targets, MAPK1, NFKB1, RELA, and TP53, were identified to be involved in the inhibitory effects of quercetin on influenza. Using the molecular docking method, we evaluated the binding affinity of each ligand (quercetin)–target and discovered that quercetin and MAPK1 showed the strongest calculated binding energy among the four ligand–target complexes. (4) Conclusion: These findings identified potential targets of quercetin and suggest quercetin as a potential drug for influenza treatment.

Network pharmacology study on the mechanism of the Chinese medicine Radix Isatidis (Banlangen) for COVID-19

Radix Isatidis (Banlangen) is a well-known traditional Chinese medicine for the treatment of different diseases and prevention of many body disorders. Besides, it also plays a pivotal role in novel coronavirus pneumonia, coronavirus disease 2019 (COVID-19). However, few researchers know its active ingredients and mechanism of action for COVID-19. To find whether Banlangen has a pharmacological effect on COVID-19. In this research, we systematically analyze Banlangen and COVID-19 through network pharmacology technology. A total of 33 active ingredients in Banlangen, 92 targets of the active ingredients, and 259 appropriate targets of COVID-19 were obtained, with 11 common targets. The analysis of the biological process of gene ontology and the enrichment of Kyoto Encyclopedia of Genes and Genomes signaling pathway suggests that Banlangen participated in the biological processes of protein phosphatase binding, tetrapyrrole binding, the apoptotic process involving cysteine-type endopeptidase activity, etc. The COVID-19 may be treated by regulating advanced glycation end products/a receptor for advanced glycation end products signaling pathway, interleukin-17 signaling pathway, tumor necrosis factor signaling pathway, sphingolipid signaling pathway, and p53 signaling pathway. Banlangen has a potential pharmacological effect on COVID-19, which has the value of further exploration in the following experiment and clinical application.

Antiviral Drug Delivery System for Enhanced Bioactivity, Better Metabolism and Pharmacokinetic Characteristics

Antiviral drugs (AvDs) are the primary resource in the global battle against viruses, including the recent fight against corona virus disease 2019 (COVID-19). Most AvDs require multiple medications, and their use frequently leads to drug resistance, since they have poor oral bioavailability and low efficacy due to their low solubility/low permeability. Characterizing the in vivo metabolism and pharmacokinetic characteristics of AvDs may help to solve the problems associated with AvDs and enhance their efficacy. In this review of AvDs, we systematically investigated their structure-based metabolic reactions and related enzymes, their cellular pharmacology, and the effects of metabolism on AvD pharmacodynamics and pharmacokinetics. We further assessed how delivery systems achieve better metabolism and pharmacology of AvDs. This review suggests that suitable nanosystems may help to achieve better pharmacological activity and pharmacokinetic behavior of AvDs by altering drug metabolism through the utilization of advanced nanotechnology and appropriate administration routes. Notably, such AvDs as ribavirin, remdesivir, favipiravir, chloroquine, lopinavir and ritonavir have been confirmed to bind to the severe acute respiratory syndrome-like coronavirus (SARS-CoV-2) receptor and thus may represent anti-COVID-19 treatments. Elucidating the metabolic and pharmacokinetic characteristics of AvDs may help pharmacologists to identify new formulations with high bioavailability and efficacy and help physicians to better treat virus-related diseases, including COVID-19.

Polygalaxanthone III downregulates inflammation in the lipopolysaccharide-stimulated RAW264.7 macrophages: A quantibody array analysis

Polygala japonica Houtt. (PJ), a member of the Polygala L. family that is suggested to exhibit detoxification properties in traditional Chinese medicine, is often used to treat upper respiratory tract infections. The anti-inflammatory effects of four main components of PJ (POL, PS-XLIX, PS-E, and PS-F) were examined using the LPS(0.3 μg·mL^-1)-stimulated RAW264.7 macrophage model. The levels of NO, ROS, and iNOS were examined to analyze the anti-inflammatory activity of POL. Additionally, the levels of extracellular inflammation-related cytokines and chemokines were measured using quantibody array. The KEGG pathway analysis was performed to examine the anti-inflammatory mechanism of POL. The levels of NO in the POL-pretreated group were significantly downregulated when compared with those in the PS-E-pretreated, PS-F-pretreated, and PS-XLIX-pretreated groups. POL significantly inhibited the changes of iNOS, ROS, and inflammatory factors caused by LPS stimulation (p < 0.001). The expression levels of IL21 and GM-CSF were examined using qPCR, while those of JAK-STAT signaling pathway-related proteins in the LPS-stimulated RAW264.7 macrophages were analyzed using western blotting. POL significantly downregulated the expression of IL-21 and GM-CSF. The anti-inflammatory mechanism of POL is mediated through the JAK-STAT pathway. Thus, this study demonstrated that POL is an anti-inflammatory component of PJ and elucidated its mechanism.

Systematic characterization of chemical constituents in Mahuang decoction by UHPLC tandem linear ion trap-Orbitrap mass spectrometry coupled with feature-based molecular networking

Comprehensive characterization of traditional Chinese medicine prescriptions has long been a hurdle due to the chemical complexity and the lack of analytical tools. Mahuang decoction is a well-known traditional Chinese medicine prescription widely used for sweating and relieving the exterior, relieving cough and asthma, but it was insufficiently chemically scrutinized. In this study, the chemical component information of Mahuang decoction was investigated by ultrahigh-performance liquid chromatography tandem linear ion trap-Orbitrap mass spectrometry. A new data processing tool, feature-based molecular networking, was introduced for grouping and elucidating the compounds. In this way, 156 chemical components were identified or tentatively characterized, including alkaloids, triterpenoid saponins, flavanone-O-glycosides, flavone-C-glycosides, and procyanidins. Thus, this research provides a solid foundation for further development of Mahuang decoction, and the adopted method is expected to be applied to other traditional Chinese medicine prescriptions.

Chinese herbal medicine: Fighting SARS-CoV-2 infection on all fronts

ETHNOPHARMACOLOGICAL RELEVANCE

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes coronavirus disease 2019 (COVID-19), a highly pathogenic virus that has spread rapidly across the entire world. There is a critical need to develop safe and effective drugs, especially broad-spectrum antiviral and organ protection agents in order to treat and prevent this dangerous disease. It is possible that Chinese herbal medicine may play an essential role in the treatment of patients with SARS-CoV-2 infection.

AIM OF THE REVIEW

We aim to review the use of Chinese herbal medicine in the treatment of COVID-19 both in vitro and in clinical practice. Our goal was to provide a better understanding of the potential therapeutic effects of Chinese herbal medicine and to establish a "Chinese protocol" for the treatment of COVID-19.

MATERIALS AND METHODS

We systematically reviewed published research relating to traditional Chinese herbal medicines and the treatment of SARS-CoV-2 from inception to the 6^th January 2021 by screening a range of digital databases (Web of Science, bioRxiv, medRxiv, China National Knowledge Infrastructure, X-MOL, Wanfang Data, Google Scholar, PubMed, Elsevier, and other resources) and public platforms relating to the management of clinical trials. We included the active ingredients of Chinese herbal medicines, monomer preparations, crude extracts, and formulas for the treatment of COVID-19.

RESULTS

In mainland China, a range of Chinese herbal medicines have been recognized as very promising anti-SARS-CoV-2 agents, including active ingredients (quercetagetin, osajin, tetrandrine, proscillaridin A, and dihydromyricetin), monomer preparations (xiyanping injection, matrine-sodium chloride injection, diammonium glycyrrhizinate enteric-coated capsules, and sodium aescinate injection), crude extracts (Scutellariae Radix extract and garlic essential oil), and formulas (Qingfei Paidu decoction, Lianhuaqingwen capsules, and Pudilan Xiaoyan oral liquid). All these agents have potential activity against SARS-CoV-2 and have attracted significant attention due to their activities both in vitro and in clinical practice.

CONCLUSIONS

As a key component of the COVID-19 treatment regimen, Chinese herbal medicines have played an irreplaceable role in the treatment of SARS-CoV-2 infection. The "Chinese protocol" has already demonstrated clear clinical importance. The use of Chinese herbal medicines that are capable of inhibiting SARS-Cov-2 infection may help to address this immediate unmet clinical need and may be attractive to other countries that are also seeking new options for effective COVID-19 treatment. Our analyses suggest that countries outside of China should also consider protocols involving Chinese herbal medicines combat this fast-spreading viral infection.

Indole-3-carboxaldehyde regulates RSV-induced inflammatory response in RAW264.7 cells by moderate inhibition of the TLR7 signaling pathway

Human respiratory syncytial virus (RSV) is highly contagious and the leading cause of severe respiratory tract illness in infants, elderly, and immunocompromised individuals. Toll-like receptor 7 (TLR7), a pattern recognition receptor recognising the ssRNA of RSV, activates proinflammatory pathways and triggers secretion of interferons (IFNs). On the one hand, the inflammatory responses help clear out virus. On the other hand, they lead to severe lung damage. Banlangen is a traditional Chinese herbal medicine commonly prescribed for respiratory virus infection treatment, but the mechanisms of action and active components remain largely unknown. In the present study, we investigated the effects of the main active components of total alkaloids from banlangen (epigoitrin, indole-3-carboxaldehyde, indole-3-acetonitrile and 4-methoxyindole-3-acetonitrile) on the RSV-induced inflammatory responses in mouse macrophage cells (RAW264.7). Our results demonstrated that RSV-induced IFN-α excessive secretion was moderately inhibited by indole-3-carboxaldehyde through downregulation of mRNA expression in a dose-dependent manner, in comparison, the inhibitory effects of ribavirin were too strong. Furthermore, we revealed that indole-3-carboxaldehyde suppressed transcription of IFN-α by inhibiting RSV-induced TLR7 expression in RAW264.7 cells. Additionally, indole-3-carboxaldehyde inhibited RSV-induced NF-κB signalling activation in a TLR7-MyD88-dependent manner. Together, our findings suggest that indole-3-carboxaldehyde inhibited RSV-induced inflammatory injury by moderate regulation of TLR7 signaling pathway and did not significantly affect the viral clearance competence of the innate immune system.

Searching for effective antiviral small molecules against influenza A virus: A patent review

Introduction: Despite the current interest caused by SARS-Cov-2, influenza continues to be one of the most serious health concerns, with an estimated 1 billion cases across the globe, including 3-5 million severe cases and 290,000-650,000 deaths worldwide. Areas covered: This manuscript reviews the efforts made in the development of small molecules for the treatment of influenza virus, primarily focused on patent applications in the last 5 years. Attention is paid to compounds targeting key functional viral proteins, such as the M2 channel, neuraminidase, and hemagglutinin, highlighting the evolution toward new ligands and scaffolds motivated by the emergence of resistant strains. Finally, the discovery of compounds against novel viral targets, such as the RNA-dependent RNA polymerase, is discussed. Expert opinion: The therapeutic potential of antiviral agents is limited by the increasing presence of resistant strains. This should encourage research on novel strategies for therapeutic intervention. In this context, the discovery of arbidol and JNJ7918 against hemagglutinin, and current efforts on RNA-dependent RNA polymerase have disclosed novel opportunities for therapeutic treatment. Studies should attempt to expand the therapeutic arsenal of anti-flu agents, often in combined therapies, to prevent future health challenges caused by influenza virus. Abbreviations: AlphaLISA: amplified luminescent proximity homogeneous assay; HA: hemagglutinin; NA: neuraminidase; RBD: receptor binding domain; RdRp: RNA-dependent RNA polymerase; SA: sialic Acid; TBHQ: tert-butyl hydroquinone; TEVC: two-electrode voltage clamp.