Baicalin inhibits TLR7/MYD88 signaling pathway activation to suppress lung inflammation in mice infected with influenza A virus

A comprehensive overview on antiviral effects of baicalein and its glucuronide derivative baicalin

Natural product-based antiviral candidates have received significant attention. However, there is a lack of sufficient research in the field of antivirals to effectively combat patterns of drug resistance. Baicalein and its glucuronide derivative baicalin are two main components extracted from Scutellaria baicalensis Georgi. They have proven to be effective against a broad range of viruses by directly killing virus particles, protecting infected cells, and targeting viral antigens on their surface, among other mechanisms. As natural products, they both possess the advantage of lower toxicity, enhanced therapeutic efficacy, and even antagonistic effects against drug-resistant viral strains. Baicalein and baicalin exhibit promising potential as potent pharmacophore scaffolds, demonstrating their antiviral properties. However, to date, no review on the antiviral effects of baicalein and baicalin has been published. This review summarizes the recent research progress on antiviral effects of baicalein and baicalin against various types of viruses both in vitro and in vivo with a focus on the dosages and underlying mechanisms. The aim is to provide a basis for the rational development and utilization of baicalein and baicalin, as well as to promote antiviral drug research. Please cite this article as: Liu XY, Xie W, Zhou HY, Zhang HQ, Jin YS. A comprehensive overview on antiviral effects of baicalein and its glucuronide derivative baicalin. J Integr Med. 2024; Epub ahead of print.

Baicalin reduces inflammation to inhibit lung cancer via targeting SOCS1/NF-κB/STAT3 axis

Inflammation affects several aspects of lung cancer progression including cell proliferation, metastasis, apoptosis, angiogenesis, and drug resistance. Baicalin, an active component of Scutellaria baicalensis Georgi, exhibits anticancer activity in various cancers. However, the effects of baicalin on lung cancer and the underlying molecular mechanisms remain largely unknown. This study is to explore the effect and mechanism of baicalin on lung cancer cell A549 and urethane-induced mouse lung cancer. A cell viability assay, colony formation assay, wound healing assay, acridine orange/ethidium bromide (AO/EB) staining assay, Western blot assay, urethane-induced mouse lung cancer model, hematoxylin and eosin (HE) staining, immunohistochemistry (IHC), and ELISA assay were performed to investigate the effects of baicalin on lung cancer in vitro and in vivo. Network pharmacology analysis, molecular docking, gene silencing assays, and LPS-induced inflammation model were utilized to explore the molecular mechanisms underlying the effect of baicalin on lung cancer. Baicalin showed significant anti-proliferative, anti-migratory, anti-inflammatory and pro-apoptotic effects in vitro; it also inhibited the progression of urethane-induced mouse lung cancer in vivo. Mechanistically, suppressor of cytokine signaling 1 (SOCS1) was the key determinant for baicalin-induced inhibition of lung cancer. Baicalin increased SOCS1 expression to inactivate the NF-κB/STAT3 pathway to inhibit lung cancer in vitro and in vivo. Taken together, baicalin reduces inflammation to inhibit lung cancer via targeting SOCS1/NF-κB/STAT3 axis, providing a prospective compound and novel target for lung cancer treatment.

Baicalin and lung diseases

Studies focusing on natural products have been conducted worldwide, and the results suggest that their natural ingredients effectively treat a wide range of illnesses. Baicalin (BIA) is a glycoside derived from the flavonoid baicalein present in Scutellaria baicalensis of the Lamiaceae family. Interestingly, BIA has been shown to protect the lungs in several animal models used in numerous studies. Therefore, we fully analyzed the data of the studies that focused on BIA's lung protective function against various injuries and included them in this review. Interestingly, BIA exhibits promising effects against acute lung injury, lung fibrosis, pulmonary embolism, and lung remodelling associated with COPD, LPS, and paraquat insecticide. BAI exhibits anticancer activity against lung cancer. Additionally, BIA potently attenuates lung damage associated with infections. BIA primarily exerts its therapeutic effects by suppressing inflammation, oxidative stress immune response, and apoptosis pathways. Nrf2/HO-1, PI3K/Akt, NF-κB, STAT3, MAPKs, TLR4, and NLRP3 are important targets in the pulmonary therapeutic effects of BIA on different lung disease models. Consequently, we recommend using it in future potential clinical applications, its contribution to treatment guidelines, and translating its promising effects to clinical practice in lung diseases.

TLR7 neo-functionalizes to sense dsRNA and trigger antiviral and antibacterial immunity in non-tetrapod vertebrates

TLR7 plays a crucial role in sensing viral ssRNA and initiating immune responses. Piscine TLR7 also responds to dsRNA challenge. dsRNA exists in almost all the viruses at specific stages. However, the mechanism on sensing dsRNA by TLR7 remains unknown. In the present study, we employed Ctenopharyngodon idella TLR7 (CiTLR7) to systematically explore the immune functions and mechanisms in teleost. CiTLR7 can directly bind not only ssRNA but also dsRNA at different patches in lysosome, recruit MyD88 as adaptor, and activate the downstream IFN pathway via SLC15A4/TASLa/TASLb/IRF5/IRF7 complex for antiviral and antibacterial infections and AP-1 pathway for pro-inflammatory cytokines. The key binding sites for dsRNA are L29 and L811 in CiTLR7. Further, we found that the function on recognizing dsRNA by TLR7 emerges in pisciformes and loses in tetrapods in evolution. This is the first report on sensing both ssRNA and dsRNA by a TLR member.

An overview of anti-SARS-CoV-2 and anti-inflammatory potential of baicalein and its metabolite baicalin: Insights into molecular mechanisms

The current Coronavirus Disease 2019 (COVID-19) pandemic, caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), is highly contagious infection that breaks the healthcare systems of several countries worldwide. Till to date, no effective antiviral drugs against COVID-19 infection have reached the market, and some repurposed drugs and vaccines are prescribed for the treatment and prevention of this disease. The currently prescribed COVID-19 vaccines are less effective against the newly emergent variants of concern of SARS-CoV-2 due to several mutations in viral spike protein and obviously there is an urgency to develop new antiviral drugs against this disease. In this review article, we systematically discussed the anti-SARS-CoV-2 and anti-inflammatory efficacy of two flavonoids, baicalein and its 7-O-glucuronide, baicalin, isolated from Scutellaria baicalensis, Oroxylum indicum, and other plants as well as their pharmacokinetics and oral bioavailability, for development of safe and effective drugs for COVID-19 treatment. Both baicalein and baicalin target the activities of viral S-, 3CL-, PL-, RdRp- and nsp13-proteins, and host mitochondrial OXPHOS for suppression of viral infection. Moreover, these compounds prevent sepsis-related inflammation and organ injury by modulation of host innate immune responses. Several nanoformulated and inclusion complexes of baicalein and baicalin have been reported to increase oral bioavailability, but their safety and efficacy in SARS-CoV-2-infected transgenic animals are not yet evaluated. Future studies on these compounds are required for use in clinical trials of COVID-19 patients.

Inhibiting virus replication and excessive inflammatory response: Mechanism of combined prescription of Ma-Xing-Shi-Gan decoction and Xiao-Chai-Hu decoction against influenza virus

ETHNOPHARMACOLOGICAL RELEVANCE

The combined prescription of two classical decoctions (Ma-Xing-Shi-Gan decoction with Xiao-Chai-Hu decoction), named as San-Yang-He-Zhi (SYHZ) decoction, has been widely used for the treatment of influenza virus (IFV) infections for decades.

AIM OF THE STUDY

This study aimed to evaluate the anti-influenza effect of SYHZ decoction and explore the underlying mechanism.

MATERIALS AND METHODS

The ingredients of SYHZ decoction were analyzed by mass spectrometry. An animal model of IFV infection was established by challenging C57BL/6J mice with PR8 virus. Three groups of mice were infected with lethal or non-lethal doses of IFV, then followed by oral administration of phosphate-buffered saline (PBS), or SYHZ, or oseltamir; blank control mice (without IFV infection) were treated with PBS. Survival rate, Lung index, colon length, body weight loss and IFV viral load were measured 7 days post infection; histology and electron-microscopy examinations of lung tissue were performed; cytokine and chemokine levels in lung and serum were measured; and the intestinal metagenome, the cecum metabolome, and the lung transcriptome were analyzed.

RESULTS

SYHZ treatment significantly improved survival rate compared with PBS (40% vs 0%); improved lung index, colon length, and body weight loss; and alleviated lung histological damage and viral load. SYHZ-treated mice had significantly lower levels of IL-1β, TNF-α, IL-6, CCL2, CXCL10 in lung and serum, and increased levels of multiple bioactive components in cecum. Pro-inflammatory cytokines, Toll- and NOD-like receptors, pro-apoptosis molecules, and lung-injury-related proteins were downregulated in SYHZ mice, whereas surfactant protein and mucin were upregulated. The NOD-like receptor pathway, Toll-like receptor pathway, and NF-κB pathway were downregulated by SYHZ treatment.

CONCLUSIONS

SYHZ decoction alleviated IFV infection in a mouse model. Multiple bioactive ingredients of SYHZ may inhibit replication of IFV and suppress excessive immune response.

Promising Role of the Scutellaria baicalensis Root Hydroxyflavone-Baicalein in the Prevention and Treatment of Human Diseases

Plant roots, due to a high content of natural antioxidants for many years, have been used in herbal medicine. It has been documented that the extract of Baikal skullcap (Scutellaria baicalensis) has hepatoprotective, calming, antiallergic, and anti-inflammatory properties. Flavonoid compounds found in the extract, including baicalein, have strong antiradical activity, which improves overall health and increases feelings of well-being. Plant-derived bioactive compounds with antioxidant activity have for a long time been used as an alternative source of medicines to treat oxidative stress-related diseases. In this review, we summarized the latest reports on one of the most important aglycones with respect to the pharmacological activity and high content in Baikal skullcap, which is 5,6,7-trihydroxyflavone (baicalein).

Pharmacological effects of baicalin in lung diseases

The flavonoids baicalin and baicalein were discovered in the root of Scutellaria baicalensis Georgi and are primarily used in traditional Chinese medicine, herbal supplements and healthcare. Recently, accumulated investigations have demonstrated the therapeutic benefits of baicalin in treating various lung diseases due to its antioxidant, anti-inflammatory, immunomodulatory, antiapoptotic, anticancer, and antiviral effects. In this review, the PubMed database and ClinicalTrials website were searched with the search string "baicalin" and "lung" for articles published between September 1970 and March 2023. We summarized the therapeutic role that baicalin plays in a variety of lung diseases, such as chronic obstructive pulmonary disease, asthma, pulmonary fibrosis, pulmonary hypertension, pulmonary infections, acute lung injury/acute respiratory distress syndrome, and lung cancer. We also discussed the underlying mechanisms of baicalin targeting in these lung diseases.

Qin-Qiao-Xiao-Du formula alleviate influenza virus infectious pneumonia through regulation gut microbiota and metabolomics

Qin-Qiao-Xiao-Du (QQXD), a traditional Chinese medicine (TCM) formula, has been used in the clinical treatment of influenza virus pneumonia. However, the effects and mechanisms of QQXD on influenza virus pneumonia remain unknown. Therefore, this study explores the mechanisms of QQXD in the treatment of influenza virus pneumonia from the point of view of intestinal flora and metabolism. The results showed that QQXD was able to reduce mortality, weight loss, lung viral load, lung index, and lung injury in influenza virus mice. A cytokine array found that the QQXD attenuated the expression of serum IL-1α, IL-4, IL-12(P70), and TNF-α. Subsequently, 16s rRNA gene sequencing showed that QQXD could increase the relative abundances of Gemmiger, Anaerofustis, Adlercreutzia, and Streptococcus and decrease those of Dehalobacteriu, Burkholderia, Prevotella, Butyrimimonas, Delftia, and others. Meanwhile, targeted metabolic profiling analysis showed that QQXD could regulate nitrogen metabolism, phenylalanine metabolism, valine, leucine, and isoleucine biosynthesis. Correlation analysis demonstrated that the regulatory effect of QQXD on the cyanoamino acid metabolism pathway was associated with changes in the abundance of Parabacteroides, Pediococcus, and Clostridium in influenza mice. In conclusion, our study revealed that QQXD can inhibit influenza virus replication, suppress cytokine storms, and protect mice from influenza virus infection pneumonia. The mechanisms are likely to be related to improved gut microbiota dysbiosis, increased intestinal carbohydrate metabolism, and up-regulated cyanoamino acid metabolism pathways.

Baicalin Inhibits Inflammation in Rats with Chronic Obstructive Pulmonary Disease by the TLR2/MYD88/NF-κBp65 Signaling Pathway

Objective

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease with a relatively high morbidity and death rate. This study aimed to investigate the inhibitory effect of baicalin (BA) on inflammation in COPD rats and its possible mechanism.

Methods

The experimental COPD of SD rats were induced by LPS, smoking, and cold stimulation, and they were randomly divided into the control group, COPD group, COPD + LB group, COPD + MB group, and COPD + HB group. The test of pulmonary function and the HE staining were carried out in COPD rats. The levels of TNF-α, IL-1β, IL-6, IL-10, and IL-8, as well as GSH, SOD, and MDA in serum, were detected by ELISA. The levels of TLR2, MYD88, TNF-α, and IL-1β mRNA in BALF were detected by qPCR. The expression of TLR2/MYD88/NF-κBp65 pathway-related proteins was also detected by the Western blot and immunohistochemistry assays.

Results

Compared to the COPD model group, BA treatment significantly improved the pulmonary function and pathologic changes, reduced the levels of TNF-α, IL-1β, IL-6, IL-10, IL-8, and MDA, and increased the levels of IL-10, SOD, and GSH in COPD rats. In addition, BA could also decrease the protein levels of MYD88, p–NF–κBp65/NF-κBp65, TLR2, and TLR4 but increase the protein level of p-IκBa/IκB in lung tissue of COPD rats.

Conclusion

BA ameliorated inflammatory response and oxidative stress in COPD rats by regulating the TLR2/MYD88/NF-κBp65 signaling pathway.

Inspiration for COVID-19 Treatment: Network Analysis and Experimental Validation of Baicalin for Cytokine Storm

Background: Cytokine storm (CS) is a systemic inflammatory syndrome and a major cause of multi-organ failure and even death in COVID-19 patients. With the increasing number of COVID-19 patients, there is an urgent need to develop effective therapeutic strategies for CS. Baicalin is an anti-inflammatory and antiviral traditional Chinese medicine. In the present study, we aimed to evaluate the therapeutic mechanism of baicalin against CS through network analysis and experimental validation, and to detect key targets of CS that may bind closely to baicalin through molecular docking. Method: Access to potential targets of baicalin and CS in public databases. We constructed the protein-protein interaction (PPI) network of baicalin and CS by Cytoscape 9.0 software and performed network topology analysis of the potential targets. Then, the hub target was identified by molecular docking technique and validated in the CS model. Finally, GO and KEGG pathway functional enrichment analysis of common targets were confirmed using R language, and the location of overlapping targets in key pathways was queried via KEGG Mapper. Result: A total of 86 overlapping targets of baicalin and CS were identified, among which MAPK14, IL2, FGF2, CASP3, PTGS2, PIK3CA, EGFR, and TNF were the core targets. Moreover, it was found that baicalin bound most closely to TNF through molecular docking, and demonstrated that baicalin can effectively inhibit the elevation of TNF-α in vitro and in vivo. Furthermore, bioenrichment analysis revealed that the TNF signaling pathway and IL-17 signaling pathway may be potential key pathways for baicalin to treat CS. Conclusion: Based on this study, baicalin was identified as a potential drug for the alleviation of CS, and the possible key targets and pathways of baicalin for the treatment of CS were elucidated to reveal the main pharmacological mechanisms.

Modulating Neurological Complications of Emerging Infectious Diseases: Mechanistic Approaches to Candidate Phytochemicals

Growing studies are revealing the critical manifestations of influenza, dengue virus (DENV) infection, Zika virus (ZIKV) disease, and Ebola virus disease (EVD) as emerging infectious diseases. However, their corresponding mechanisms of major complications headed for neuronal dysfunction are not entirely understood. From the mechanistic point of view, inflammatory/oxidative mediators are activated during emerging infectious diseases towards less cell migration, neurogenesis impairment, and neuronal death. Accordingly, the virus life cycle and associated enzymes, as well as host receptors, cytokine storm, and multiple signaling mediators, are the leading players of emerging infectious diseases. Consequently, chemokines, interleukins, interferons, carbohydrate molecules, toll-like receptors (TLRs), and tyrosine kinases are leading orchestrates of peripheral and central complications which are in near interconnections. Some of the resulting neuronal manifestations have attracted much attention, including inflammatory polyneuropathy, encephalopathy, meningitis, myelitis, stroke, Guillain-Barré syndrome (GBS), radiculomyelitis, meningoencephalitis, memory loss, headaches, cranial nerve abnormalities, tremor, and seizure. The complex pathophysiological mechanism behind the aforementioned complications urges the need for finding multi-target agents with higher efficacy and lower side effects. In recent decades, the natural kingdom has been highlighted as promising neuroprotective natural products in modulating several dysregulated signaling pathways/mediators. The present study provides neuronal manifestations of some emerging infectious diseases and underlying pathophysiological mechanisms. Besides, a mechanistic-based strategy is developed to introduce candidate natural products as promising multi-target agents in combating major dysregulated pathways towards neuroprotection in influenza, DENV infection, ZIKV disease, and EVD.

Antiviral Properties of Baicalin: a Concise Review

Baicalin is one of the bioactive flavonoid glycosides isolated from the dried root of Scutellaria baicalensis Georgi, Lamiaceae, with antiviral properties. In recent years, the antiviral activity of baicalin has been widely investigated to explore its molecular mechanism of action. In this mini-review, the molecular mechanisms of action of baicalin as an antiviral agent are evaluated, which included three categories: the inhibition or stimulation of JAK/STAT, TLRs, and NF-κB pathways; up or down modulation of the expression levels of IFN, IL, SOCS1/3, PKR protein, Mx1 protein, and AP-1 protein; and inhibition of cell apoptosis caused by virus infection. In addition, clinical studies of baicalin are also discussed. This literature search suggested that baicalin can serve as a potential candidate for the development of a novel broad-spectrum antiviral drug.

In Silico Target Analysis of Treatment for COVID-19 Using Huang-Lian-Shang-Qing-Wan, a Traditional Chinese Medicine Formula

Due to the significantly negative impact of the coronavirus (CoV) disease (COVID-19) pandemic on the health of the community and the economy, it remains urgent and necessary to develop a safe and effective treatment method for COVID-19. Huang-Lian-Shang-Qing-Wan (HLSQW) is a herbal formula of traditional Chinese medicine (TCM) that has been applied extensively for treating “wind-heat-associated” symptoms in the upper parts of the body. The objective of the present in silico study was to investigate the potential effects of HLSQW in the context of severe acute respiratory syndrome (SARS)-CoV-2 infection. We analyzed the possible interactions between bioactive compounds within HLSQW on targets that may confer antiviral activity using network pharmacology and pharmacophore-based screening. HLSQW was found to potentially target a number of pathways and the expression of various genes to regulate cell physiology and, consequently, the anti-viral effects against SARS-CoV-2. Bioactive compounds contained within HLSQW may exert combined effects to reduce the production of proinflammatory factors, which may trigger the “cytokine storm” in patients with severe COVID-19. Results from molecular modeling suggested that the bioactive HLSQW components puerarin, baicalin, and daidzin exhibit high binding affinity to the active site of 3-chymotrypsin-like cysteine protease (3CLpro) to form stable ligand-protein complexes, thereby suppressing SARS-CoV-2 replication. In addition, our results also demonstrated protective effects of the HLSQW extract against cell injury induced by the proinflammatory cytokines tumor necrosis factor-α, interleukin (IL)-1β, and IL-6, against reactive oxygen species production and nuclear factor-κB activity in normal human lung cells in vitro. To conclude, HLSQW is a potential TCM remedy that warrants further study with the aim of developing an effective treatment for COVID-19 in the future.

A review of pharmacological and pharmacokinetic properties of Forsythiaside A

Traditional Chinese medicine plays a significant role in the treatment of various diseases and has attracted increasing attention for clinical applications. Forsythiae Fructus, the dried fruit of Forsythia suspensa (Thunb.) Vahl, is a widely used Chinese medicinal herb in clinic for its extensive pharmacological activities. Forsythiaside A is the main active index component isolated from Forsythiae Fructus and possesses prominent bioactivities. Modern pharmacological studies have confirmed that Forsythiaside A exhibits significant activities in treating various diseases, including inflammation, virus infection, neurodegeneration, oxidative stress, liver injury, and bacterial infection. In this review, the pharmacological activities of Forsythiaside A have been comprehensively reviewed and summarized. According to the data, Forsythiaside A shows remarkable anti-inflammation, antivirus, neuroprotection, antioxidant, hepatoprotection, and antibacterial activities through regulating multiple signaling transduction pathways such as NF-κB, MAPK, JAK/STAT, Nrf2, RLRs, TRAF, TLR7, and ER stress. In addition, the toxicity and pharmacokinetic properties of Forsythiaside A are also discussed in this review, thus providing a solid foundation and evidence for further studies to explore novel effective drugs from Chinese medicine monomers.

Broad Anti-Viral Capacities of Lian-Hua-Qing-Wen Capsule and Jin-Hua-Qing-Gan Granule and Rational use Against COVID-19 Based on Literature Mining

The novel coronavirus disease 2019 (COVID-19) has become a matter of international concern as the disease is spreading exponentially. Statistics showed that infected patients in China who received combined treatment of Traditional Chinese Medicine and modern medicine exhibited lower fatality rate and relatively better clinical outcomes. Both Lian-Hua-Qing-Wen Capsule (LHQWC) and Jin-Hua-Qing-Gan Granule (JHQGG) have been recommended by China Food and Drug Administration for the treatment of COVID-19 and have played a vital role in the prevention of a variety of viral infections. Here, we desired to analyze the broad-spectrum anti-viral capacities of LHQWC and JHQGG, and to compare their pharmacological functions for rational clinical applications. Based on literature mining, we found that both LHQWC and JHQGG were endowed with multiple antiviral activities by both targeting viral life cycle and regulating host immune responses and inflammation. In addition, from literature analyzed, JHQGG is more potent in modulating viral life cycle, whereas LHQWC exhibits better efficacies in regulating host anti-viral responses. When translating into clinical applications, oral administration of LHQWC could be more beneficial for patients with insufficient immune functions or for patients with alleviated symptoms after treatment with JHQGG.

Protective effect of Asarum sieboldii essential oil on ovalbumin induced allergic rhinitis in rat

BACKGROUND

The study was aimed to investigate the protective effect of Asarum sieboldii Miq. essential oil (AEO) on ovalbumin (OVA)-induced allergic rhinitis (AR) in rats.

METHODS AND RESULTS

Sixty Sprague-Dawley male rats were randomly divided into six groups (n=10): control, model, cetirizine (Cet, 4.65 g/kg), and AEO (0.5, 1.5, 3 g/kg) groups. All animals except the control group received repeated intranasal instillation with 20 μl of 20% OVA in Al(OH)3 saline solvent for 15 days. The control group was intranasally instilled with 5 mg/ml of Al(OH)3 instead of the same procedure. In the 15 days, Cet and AEO were orally administrated for 28 days. At the end of the drug administration, 20 μl of 5% OVA was given to animals to stimulate allergic reaction, then the rat behavioral detection, assessment of the patho-morphological changes in nasal mucosa, and the serum biomarkers were determined. The result showed that AEO could significantly reduce the amount of nasal secretions, sneezing, and the degree of nasal scratching in AR rats with EC50 = 1.5 and 2.8 g/kg, respectively. The degree of nasal mucosal inflammation in AEO group improved, the levels of immunoglobulin E (IgE), histamine, IL-4, IL-5, IL-17 were decreased, and the level of IFN-γ was increased obviously with EC50 = 2 g/kg.

CONCLUSION

The study suggested that the possible mechanism might be related with the inhibition of histamine release and regulation of the cytokine levels, which plays an important role in the treatment of AR.

Baicalin ameliorates Mycoplasma gallisepticum-induced lung inflammation in chicken by inhibiting TLR6-mediated NF-κB signalling

1. Mycoplasma gallisepticum (MG) causes severe lung inflammation and cell damage by activating toll-like receptor (TLR) signalling, the nuclear factor-kappaB (NF-κB) pathway and pro-inflammatory cytokine gene expression. Baicalin (BA) is a flavonoid extracted from Scutellaria baicalensis, which possesses anti-inflammatory and anti-bacterial properties. This study investigated the effect of BA in MG-induced lung inflammation and its potential mechanism in MG-infected chicken embryo lungs and DF-1 cells.2. The histopathological examination result showed that BA treatment alleviated MG-induced lung pathological changes. In addition, CCK-8 and cell cycle assays showed that BA treatment inhibited MG-induced cell proliferation and cell cycle progression in DF-1 cells.3. The ELISA and RT-qPCR results demonstrated that BA treatment decreased the expression of interleukin-1beta (IL-1β), IL-6, and tumour necrosis factor-alpha (TNF-α) both in MG-infected chicken embryo lungs and DF-1 cells.4. The results revealed that BA inhibited mRNA expression levels of toll-like receptor-6 (TLR6), myeloid differentiation primary response gene-88 (MyD88) and nuclear factor-κB (NF-κB), and the nuclear translocation of NF-κB-p655. In conclusion, the results showed that BA has a protective effect against MG-induced lung inflammation in chicken by inhibiting the TLR6-mediated NF-κB signalling.

Preliminary study of Yinhuapinggan granule against H1N1 influenza virus infection in mice through inhibition of apoptosis

CONTEXT

Yinhuapinggan granule (YHPG) is frequently used for treating fever, cough, and viral pneumonia in traditional Chinese medicine.

OBJECTIVE

This study investigated the antiviral effects of YHPG in H1N1 influenza virus (IFV)-infected mice and its possible mechanism.

MATERIALS AND METHODS

ICR mice were intranasally infected with 10 LD₅₀ viral dose of IFV and then oral administration of YHPG (6, 12, and 18 g/kg) or oseltamivir (positive control) once a day for 2 or 4 consecutive days, six mice in each group. The lung, spleen and thymus indexes of IFV-infected mice, the expression of viral loads and pathological changes in lung tissues were performed to evaluate the antiviral effects of YHPG. Real-time PCR, immunohistochemistry and western blot assays were used to determine the expression of Bax, Bcl-2 and caspase-3.

RESULTS

LD₅₀ in mice was 10^-3.5/0.02 mL. YHPG (6, 12, and 18 g/kg) dose-dependently decreased the lung index and viral load; the inhibition ratio of lung index was 5.31, 18.22, and 34.06%, respectively. Further detection revealed that YHPG (12 and 18 g/kg) significantly attenuated lung pathological changes, and increased the spleen and thymus indexes. Moreover, YHPG significantly down-regulated the mRNA and protein expression of Bax and caspase-3 in lung tissues of mice infected with IFV, and up-regulated the expression of Bcl-2.

CONCLUSIONS

YHPG has significant antiviral effects in IFV-infected mice, partially by inhibiting influenza virus replication and regulating the occurrence of apoptosis induced by influenza virus infection, suggesting that YHPG may be a promising antiviral agent with potential clinical application prospects.

Role of Traditional Chinese Medicine in the Management of Viral Pneumonia

Viral pneumonia is one kind of acute respiratory tract infection caused by the virus. There have been many outbreaks of viral pneumonia with high contagiousness and mortality both in China and abroad, such as the great influenza in 1918, the severe acute respiratory syndrome (SARS) coronavirus in 2003, the Influenza A (H1N1) virus in 2009, and the Middle East Respiratory Syndrome coronavirus (MERS-CoV) in 2012 and the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2019. These outbreaks and/or pandemic have significant impact on human life, social behaviors, and economic development. Moreover, no specific drug has been developed for these viruses. Traditional Chinese medicine (TCM) plays an important role in the treatment of viral pneumonia during these outbreaks especially in SARS and SARS-CoV-2 because studies suggest that TCM formulations may target several aspects of the disease and may have lesser side effects than manufactured pharmaceuticals. In recent years, a lot of clinicians and researchers have made a series of in-depth explorations and investigations on the treatment of viral pneumonia with TCM, which have understood TCM therapeutic mechanisms more specifically and clearly. But critical analysis of this research in addition to further studies are needed to assess the potential of TCM in the treatment of viral pneumonia.

Immunological regulatory effect of flavonoid baicalin on innate immune toll-like receptors

As an essential component of the innate immune system, Toll-like receptors (TLRs) are a family of well-recognized ligand-binding receptors found in various organisms and initiate host immune responses. Activation of TLRs signaling pathways lead to the induction of numerous genes that function in host defense. Baicalin is a natural compound from the dry raw root of Scutellaria baicalensis (S. baicalensis) and it has been found to exhibit several pharmaceutical actions, such as anti-inflammation, anti-tumor and antivirus. These biological activities are mainly related to the regulatory effect of baicalin on the host immune response. In this review, we provide an overview of the regulation of baicalin on TLRs signaling pathways in various pathological conditions, and highlight potential targets for the development of the regulatory effect of natural compound from traditional Chinese medicine on innate immune system.

Gegen Qinlian Decoction Downregulates the TLR7 Signalling Pathway to Control Influenza A Virus Infection

ETHNOPHARMACOLOGICAL RELEVANCE

In recent years, Gegen Qinlian decoction (GQD) has been applied to treat influenza virus infection, and its clinical effectiveness has been shown. However, the potential mechanism by which GQD acts on influenza A virus (IAV) has not been fully elucidated. Traditional Chinese medicine (TCM) formulas are well known to have multiple targets and effects. Our previous experiments examined the mechanism by which TCM can be used to treat influenza from the perspective of the influenza immune mechanism.

AIM OF THE STUDY

To explore the possible mechanism by which GQD affects mice infected with the FM1 strain of influenza virus.

MATERIALS AND METHODS

Forty-eight C57BL/6 mice were divided randomly into four groups: a normal control (NG) group, an IAV infection (VG) group, an IAV + oseltamivir (30.44 mg/kg) treatment (VO) group, and an IAV + GQD (9.74 g/kg) treatment (VQ) group. We also grouped forty-eight Toll-like receptor 7 knockout (TLR7^-/-) mice in the same manner. The pulmonary mRNA expression of TLR7, myeloid differentiation factor 88 (MyD88), and nuclear factor (NF)-κB p65 was measured by RT-qPCR, and the pulmonary protein expression of TLR7, MyD88, and NF-κB p65 was measured by western blot. The proportions of T helper (Th) 1, Th2, Th17 and regulatory T (Treg) cells were measured by flow cytometry.

RESULTS

IAV infection led to low body weights and high viral load. Compared with those in the NG group, the mRNA expression levels of TLR7, MyD88, and NF-κB p65 in the VG group were upregulated (P < 0.05). However, the mRNA and protein expression levels of TLR7, MyD88, and NF-κB p65 were lower in the VO and VQ groups than in the VG group (P < 0.05). IAV infection led to increased proportions of Th1/Th2 and Th17/Treg cells in the VG group. In the VO and VQ groups, both Th2 and Th1 cell numbers were increased, resulting in a lower Th1/Th2 proportion than that in the VG group.

CONCLUSIONS

GQD downregulated the expression of some key TLR signalling pathway factors. GQD also affected the differentiation of CD4⁺ T cells, thereby exerting a protective systemic effect on influenza virus infection. In conclusion, GQD activated a balanced inflammatory response in the host to limit immune pathological injury and improve clinical and survival outcomes.

Baicalin inhibits influenza virus A replication via activation of type I IFN signaling by reducing miR‑146a

Influenza virus A (IVA) is one of the predominant causative agents of the seasonal flu and has become an important cause of morbidity worldwide. Great efforts have been paid to develop vaccines against IVA. However, due to antigenic drift in influenza virus A and rapid emergence of drug-resistant strains, current available vaccines or anti-IVA chemotherapeutics are consistently inefficient. Hence, various more broadly effective drugs have become important for the prevention and treatment of IVA. Of these drugs, baicalin, a flavonoid isolated from Radix Scutellaria, is a promising example. However, little is known in regards to its pharmacological mechanism. Here, it was demonstrated that baicalin inhibits the H1N1 and H3N2 viruses in A549 cells. Subsequently, it was found that miR-146a was markedly downregulated by treatment of baicalin. Additionally, further experiments revealed that miR-146a was able to promote the replication of H1N1 and H3N2 by targeting TNF receptor-associated factor 6 (TRAF6), a pivotal adaptor in the interferon (IFN) production signaling pathway, to downregulate type I IFN production, and enrichment of miR-146a eliminated the anti-IVA effects of baicalin on the H1N1 and H3N2 viruses. Additionally, in vivo experiments demonstrated that baicalin could protect mice during H1N1 infection. Taken together, our findings firstly illustrated the anti-IVA molecular mechanism of baicalin and provide new evidence for targeting miRNAs to prevent and treat viral infection, such as the H1N1 and H3N2 viruses.

Effects of Gui Zhi Ma Huang Ge Ban Tang on the TLR7 Pathway in Influenza Virus Infected Mouse Lungs in a Cold Environment

OBJECTIVE

We wished to investigate the effects of the traditional Chinese medicine Gui Zhi Ma Huang Ge Ban Tang on controlling influenza A virus (IAV) infection and improving inflammation in mouse lungs.

METHOD

Mice were maintained in normal and cold environments and infected with IAV by intranasal application, respectively. Real-time quantitative polymerase chain reaction was used to measure mRNA expression of TLR7, myeloid differentiation primary response 88 (MyD88), and nuclear factor-kappa B (NF-κB)p65 in the TLR7 signaling pathway and virus replication in lungs. Western blotting was used to measure expression levels of TLR7, MyD88, and NF-κB p65 proteins. Flow cytometry was used to detect the proportion of T-helper (Th)1/Th2 and Th17/T-regulatory (Treg) cells.

RESULTS

Application of Gui Zhi Ma Huang Ge Ban Tang in influenza-infected mice in a cold environment showed (i) downregulation of TLR7, MyD88, and NF-κBp65; (ii) inhibition of transcriptional activities of promoters coding for TLR7, MyD88, and NF-κBp65; (iii) reduction in the proportion of Th1/Th2 and Th17/Treg cells.

CONCLUSIONS

Gui Zhi Ma Huang Ge Ban Tang had a good therapeutic effect on mice infected with IAV, especially in the cold environment. It could reduce lung inflammation in mice significantly and elicit an anti-influenza effect by downregulating expression of the key factors in TLR7 signaling pathway.

Dioscin prevents LPS‑induced acute lung injury through inhibiting the TLR4/MyD88 signaling pathway via upregulation of HSP70

Dioscin, as a type of important natural steroidal saponin, has widespread sources, primarily from the fenugreek plant, which is an important raw material in the production of synthetic steroid hormone drugs. Dioscin has anti‑tumor, anti‑inflammatory, antioxidant and other significant pharmacological effects with high medicinal value. The present work aimed to research the protective effect and underlying mechanisms by which dioscin prevents acute lung injury (ALI). Mice were injected with 5 mg/kg LPS to induce lung injury. Mice were treated with dioscin (20, 40 and 60 mg/kg) following LPS‑induced lung injury. Treatment with dioscin significantly decreased total number of alveolar macrophages, water content of lung and total protein concentration in ALI mice. Dioscin treatment significantly suppressed the ALI‑induced interleukin (IL)‑1B, IL‑6, tumor necrosis factor‑α, nuclear factor (NF)‑κB, myeloperoxidase, interferon‑γ and intercellular adhesion molecule‑1 activities in ALI rats. Following this, the authors identified that dioscin significantly also suppressed cyclooxygenase‑2, heat shock protein 70, Toll‑like receptor 4, MyD88 and NF‑κB protein expression in ALI rats. The results suggested that dioscin prevents LPS‑induced ALI through inhibiting the TLR4/MyD88 signaling pathway via upregulation of HSP70.

Baicalin Downregulates RLRs Signaling Pathway to Control Influenza A Virus Infection and Improve the Prognosis

The objective of this study is to investigate the effects of baicalin on controlling the pulmonary infection and improving the prognosis in influenza A virus (IAV) infection. PCR and western blot were used to measure the changes of some key factors in RLRs signaling pathway. MSD electrochemiluminescence was used to measure the expression of pulmonary inflammatory cytokines including IFN-γ, TNF-α, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p70, and KC/GRO. Flow cytometry was used to detect the proportion of Th1, Th2, Th17, and Treg. The results showed that IAV infection led to low body weight and high viral load and high expression of RIG-I, IRF3, IRF7, and NF-κB mRNA, as well as RIG-I and NF-κB p65 protein. However, baicalin reduced the rate of body weight loss, inhibited virus replication, and downregulated the key factors of the RLRs signaling pathway. Besides, baicalin reduced the high expression inflammatory cytokines in lung and decreased the ratios of Th1/Th2 and Th17/Treg to arouse a brief but not overviolent inflammatory response. Therefore, baicalin activated a balanced host inflammatory response to limit immunopathologic injury, which was helpful to the improvement of clinical and survival outcomes.

Baicalin Suppresses Hypoxia-Reoxygenation-Induced Arterial Endothelial Cell Apoptosis via Suppressing PKCδ/p53 Signaling

Background

This study was aimed to investigate the protective role of baicalin on vascular endothelium exposed to ischemia reperfusion injury and the involved molecular mechanisms.

Material/Methods

Cultured human arterial endothelial cells (HAECs) were exposed to hypoxia/deoxygenation (H/R). Cells were also treated with baicalin at serially diluted concentrations. Cells were also treated with PKC activator PEP005 or specific siRNA against protein kinase Cδ (PKCδ). MTT assay was used to evaluate the cell viabilities. Flow cytometry was used to detect cell apoptosis. The protein phosphorylation and expression levels were determined by Western blotting.

Results

PKCδ-siRNA transfection increased cell viabilities and reduced cell apoptosis in HAECs exposed to H/R. Baicalin treatment preserved cell viabilities and reduced apoptosis of H/R-exposed HAECs in a concentration-dependent manner. Baicalin treatment reduced phosphorylation levels of PKCδ and p53, as well as the expression levels of active caspase3 and bax in HAECs exposed to H/R. The treatment of PKC activator PEP005 impaired the protective effects of baicalin in increasing cell viabilities and reducing apoptosis in HAECs exposed to H/R.

Conclusions

Baicalin exerts vascular a protective effect on HAECs exposed to H/R by reducing cell apoptosis. The PKCδ/p53 apoptotic signaling pathway was the pharmacological target of baicalin.

Identifying novel antiviral targets against enterovirus 71: where are we?

Human enterovirus 71 (HEV71) has been considered as an essential human pathogen, which causes hand, foot and mouth disease in young children. Several HEV71 outbreaks have been observed in many Asia-Pacific countries for the past two decades with significant fatalities. However, there are no competent vaccines or antivirals against HEV71 infection to date. Thus, it is of critical priority to delve into the search for anti-HEV71 agents. Prior to this, there is a need to gain knowledge about the distinct targets of HEV71 that are available and that have been exploited for antiviral therapy. This review aims to provide a better understanding of HEV71 virology and feature potential antivirals for progressive clinical development with respect to their elucidated mechanistic actions.

San-Huang-Xie-Xin-Tang Constituents Exert Drug-Drug Interaction of Mutual Reinforcement at Both Pharmacodynamics and Pharmacokinetic Level: A Review

Inflammatory disorders underlie varieties of human diseases. San-Huang-Xie-xin-Tang (SHXXT), composed with Rhizoma Rhei (Rheum palmatum L.), Rhizoma Coptidis (Coptis chinensis Franch), and Radix Scutellaria (Scutellaria baicalensis Georgi), is a famous formula which has been widely used in the fight against inflammatory abnormalities. Mutual reinforcement is one of the basic theories of traditional Chinese medicine. Here this article reviewed and analyzed the recent research on (1) How the main constituents of SHXXT impact on inflammation-associated signaling pathway molecules. (2) The interaction between the main constituents and efflux pumps or intestinal transporters. The goal of this work was to, (1) Provide evidence to support the theory of mutual reinforcement. (2) Clarify the key targets of SHXXT and suggest which targets need further investigation. (3) Give advice for the clinical use of SHXXT to elevated the absorption of main constituents and eventually promote oral bioavailability. We search literatures in scientific databases with key words of “each main SHXXT constituent,” in combination with “each main inflammatory pathway target molecule” or each main intestinal transporter, respectively. We report the effect of five main constituents on target molecules which lies in three main inflammatory signaling pathways, we as well investigate the interaction between constituents and intestinal transporter. We conclude, (1) The synergistic effect of constituents at both levels confirm the mutual reinforcement theory of TCM as it is proven in this work. (2) The effect of main constituents on downstream targets in nuclear need more further investigation. (3) Drug elevating the absorption of rhein, berberine and baicalein can be employed to promote oral bioavailability of SHXXT.

Baicalin from Scutellaria baicalensis blocks respiratory syncytial virus (RSV) infection and reduces inflammatory cell infiltration and lung injury in mice

The roots of Scutellaria baicalensis has been used as a remedy for inflammatory and infective diseases for thousands of years. We evaluated the antiviral activity against respiratory syncytial virus (RSV) infection, the leading cause of childhood infection and hospitalization. By fractionation and chromatographic analysis, we determined that baicalin was responsible for the antiviral activity of S. baicalensis against RSV infection. The concentration for 50% inhibition (IC₅₀) of RSV infection was determined at 19.9 ± 1.8 μM, while the 50% cytotoxic concentration (CC₅₀) was measured at 370 ± 10 μM. We then used a mouse model of RSV infection to further demonstrate baicalin antiviral effect. RSV infection caused significant lung injury and proinflammatory response, including CD4 and CD8 T lymphocyte infiltration. Baicalin treatment resulted in reduction of T lymphocyte infiltration and gene expression of proinflammatory factors, while the treatment moderately reduced RSV titers recovered from the lung tissues. T lymphocyte infiltration and cytotoxic T lymphocyte modulated tissue damage has been identified critical factors of RSV disease. The study therefore demonstrates that baicalin subjugates RSV disease through antiviral and anti-inflammatory effect.

Baicalin attenuates lipopolysaccharide induced inflammation and apoptosis of cow mammary epithelial cells by regulating NF-κB and HSP72

Baicalin is the main ingredient of traditional Chinese herbal medicine, Scutellaria baicalensis, which has been widely used clinically as an anti-inflammatory agent. However, molecular mechanism of action of this drug is not yet clear. In the present study, the protective mechanism of baicalin against lipopolysaccharide (LPS) induced inflammatory injury in cow mammary epithelial cells (CMECs) was explored. For this purpose, in vitro cultured CMECs were treated with baicalin (10μg/mL) and LPS (10μg/mL) for 24 and 12h, respectively, and the cell viability was measured by using cell counting kit-8 (CCK-8). The results revealed that LPS induced inflammatory responses, as p-p65/p65 and p-IκBα/IκBα ratios and TNF-α and IL-1β production was increased in the CMECs. Both Bcl-2/Bax ratio and cell viability were decreased and caspase-3 cleaved following LPS treatment, indicating apoptosis of CMECs. Moreover, both LPS and baicalin increased HSP72 expression of the CMECs. However, cellular inflammatory responses and apoptosis were significantly reduced in baicalin treated CMECs. In conclusion, baicalin ameliorated inflammation and apoptosis of the CMECs induced by LPS via inhibiting NF-κB activation and up regulation of HSP72.

Forsythoside A Controls Influenza A Virus Infection and Improves the Prognosis by Inhibiting Virus Replication in Mice

OBJECTIVE

The objective of this study was to observe the effects of forsythoside A on controlling influenza A virus (IAV) infection and improving the prognosis of IAV infection.

METHODS

Forty-eight SPF C57BL/6j mice were randomly divided into the following four groups: Group A: normal control group (normal con); Group B: IAV control group (V con); Group C: IAV+ oseltamivir treatment group (V oseltamivir; 0.78 mg/mL, 0.2 mL/mouse/day); Group D: IAV+ forsythoside A treatment group (V FTA; 2 μg/mL, 0.2 mL/mouse/day). Real-time fluorescence quantitative PCR (RT-qPCR) was used to measure mRNA expression of the TLR7, MyD88, TRAF6, IRAK4 and NF-κB p65 mRNA in TLR7 signaling pathway and the virus replication level in lung. Western blot was used to measure TLR7, MyD88 and NF-κB p65 protein. Flow cytometry was used to detect the proportion of the T cell subsets Th1/Th2 and Th17/Treg.

RESULTS

The body weight began to decrease after IAV infection, while FTA and oseltamivir could reduce the rate of body weight loss. The pathological damages in the FTA and oseltamivir group were less serious. TLR7, MyD88, TRAF6, IRAK4 and NF-κB p65 mRNA were up-regulated after virus infection (p < 0.01) while down-regulated after oseltamivir and FTA treatment (p < 0.01). The results of TLR7, MyD88 and NF-κB p65 protein consisted with correlative mRNA. Flow cytometry showed the Th1/Th2 differentiated towards Th2, and the Th17/Treg cells differentiated towards Treg after FTA treatment.

CONCLUSIONS

Our study suggests forsythoside A can control influenza A virus infection and improve the prognosis of IAV infection by inhibiting influenza A virus replication.

Mosla scabra flavonoids ameliorate the influenza A virus-induced lung injury and water transport abnormality via the inhibition of PRR and AQP signaling pathways in mice

ETHNOPHARMACROLOGICAL RELEVANCE

Mosla scabra (Thunb.) C.Y. Wu and H.W. Li has been used as a traditional medicinal herb for centuries in East Asian countries. It has antibacterial, antiviral, antioxidant, anti-inflammatory and immunomodulatory effects. In folk medicine, it is used as a remedy for the treatment of pulmonary diseases, such as fever, cold, cough, pulmonary edema and emphysema.

AIM OF THE STUDY

This study was to investigate the protective mechanism of total flavonoids from M. scabra (MF) in influenza A virus (IAV)-infected mice.

MATERIALS AND METHODS

The mice were infected with IAV and then were treated daily with MF for five days. At the end of the experiment, the levels of inflammatory-related cytokines (IFN-α, IL-6, TNF-α and IL-1β) were determined by ELISA. Pathological changes of lung tissue were examined by H&E staining. The protein expressions of AQP5, p-p38, caspase-3 and NF-κB p65 were detected by western blot analysis while the gene expressions of key effectors in AQP5 and PRRs signaling pathways were detected by real-time Fluorescence Quantitative Polymerase Chain Reaction (RFQ-PCR) analysis.

RESULTS

The results showed that treatment with MF at doses of 120-360mg/kg for five days to IAV-infected mice significantly attenuated IAV-induced pulmonary injury and decreased the serum levels of IL-6, TNF-α and IL-1β, but increased IFN-α levels. MF treatment could up-regulate the mRNA expressions of TLR-7, RIG-1, TRAF6, Bcl-2, Bax, VIPR1, PKCα and AQP5 and down-regulate caspase-3 and NF-κB p65 protein expression.

CONCLUSION

Treatment with MF could significantly alleviate IAV-induced pulmonary inflammation, apoptosis and water transport abnormality, which was probably through the regulation of TLR7, RIG-1 and AQP5 signaling pathway.

Role of Baicalin in Anti-Influenza Virus A as a Potent Inducer of IFN-Gamma

Baicalin (BA) is a flavonoid compound purified from Scutellaria baicalensis Georgi and has been shown to possess a potent inhibitory activity against viruses. However, the role of BA in anti-influenza virus has not been extensively studied, and the immunological mechanism of BA in antiviral activity remains unknown. Here, we observed that BA could protect mice from infection by influenza virus A/PR/8/34 (H₁N₁), associated with increasing IFN-γ production, but presented no effects in IFN-γ or IFN-γ receptor deficient mice. Further study indicated that BA could inhibit A/PR/8/34 replication through IFN-γ in human PBMC. Moreover, BA can directly induce IFN-γ production in human CD4⁺ and CD8⁺ T cells and NK cells, and activate JAK/STAT-1 signaling pathway. Collectively, BA exhibited anti-influenza virus A (H₁N₁) activity in vitro and in vivo as a potent inducer of IFN-γ in major IFN-γ producing cells.

The Antiviral Effect of Baicalin on Enterovirus 71 In Vitro

Baicalin is a flavonoid compound extracted from Scutellaria roots that has been reported to possess antibacterial, anti-inflammatory, and antiviral activities. However, the antiviral effect of baicalin on enterovirus 71 (EV71) is still unknown. In this study, we found that baicalin showed inhibitory activity on EV71 infection and was independent of direct virucidal or prophylactic effect and inhibitory viral absorption. The expressions of EV71/3D mRNA and polymerase were significantly blocked by baicalin treatment at early stages of EV71 infection. In addition, baicalin could decrease the expressions of FasL and caspase-3, as well as inhibit the apoptosis of EV71-infected human embryonal rhabdomyosarcoma (RD) cells. Altogether, these results indicate that baicalin exhibits potent antiviral effect on EV71 infection, probably through inhibiting EV71/3D polymerase expression and Fas/FasL signaling pathways.

Protective effects of baicalin on LPS-induced injury in intestinal epithelial cells and intercellular tight junctions

AIMS

To investigate the protective effects and mechanisms of baicalin on lipopolysaccharide (LPS)-induced injury in intestinal epithelial cells and intercellular tight junctions.

METHODS

IEC-6 cells were stimulated with LPS (1.0 μg/mL), with or without baicalin, for 24 h. The levels of the inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α were determined using ELISA. Quantitative real-time PCR was used for determining the mRNA expression level of claudin-3, occludin, and ZO-1; Western blot and immunofluorescence analysis were used for analyzing the expression level and the distribution patterns of ZO-1 protein.

RESULTS

Pretreatment with baicalin (10.0 μg/mL) improved LPS-stimulated cell viability and repressed IL-6 and TNF-α levels. In addition, pretreatment with baicalin up-regulated mRNA and protein expression levels of ZO-1 and kept the protein intact in IEC-6 cells injured with LPS.

CONCLUSION

Baicalin has the capacity to protect IEC-6 cells and the intercellular tight junctions from LPS-induced injury. The mechanisms may be associated with inhibiting the production of inflammatory cytokines, and up-regulating the mRNA and protein expression of ZO-1.

Compounds with anti-influenza activity: present and future of strategies for the optimal treatment and management of influenza. Part II: Future compounds against influenza virus

In the first part of this overview, we described the life cycle of the influenza virus and the pharmacological action of the currently available drugs. This second part provides an overview of the molecular mechanisms and targets of still-experimental drugs for the treatment and management of influenza. Briefly, we can distinguish between compounds with anti-influenza activity that target influenza virus proteins or genes, and molecules that target host components that are essential for viral replication and propagation. These latter compounds have been developed quite recently. Among the first group, we will focus especially on hemagglutinin, M2 channel and neuraminidase inhibitors. The second group of compounds may pave the way for personalized treatment and influenza management. Combination therapies are also discussed. In recent decades, few antiviral molecules against influenza virus infections have been available; this has conditioned their use during human and animal outbreaks. Indeed, during seasonal and pandemic outbreaks, antiviral drugs have usually been administered in mono-therapy and, sometimes, in an uncontrolled manner to farm animals. This has led to the emergence of viral strains displaying resistance, especially to compounds of the amantadane family. For this reason, it is particularly important to develop new antiviral drugs against influenza viruses. Indeed, although vaccination is the most powerful means of mitigating the effects of influenza epidemics, antiviral drugs can be very useful, particularly in delaying the spread of new pandemic viruses, thereby enabling manufacturers to prepare large quantities of pandemic vaccine. In addition, antiviral drugs are particularly valuable in complicated cases of influenza, especially in hospitalized patients. To write this overview, we mined various databases, including Embase, PubChem, DrugBank and Chemical Abstracts Service, and patent repositories.

Baicalin inhibits autophagy induced by influenza A virus H3N2

Baicalin, a natural product isolated from Scutellariaradix, has been reported to have significant in vivo and in vitro anti-influenza virus activity, but the underlying mechanism remains poorly understood. In this study, we found that baicalin inhibited autophagy induced by influenza virus A3/Beijing/30/95 (H3N2) in both A549 and Ana-1 cells. The results showed that H3N2 induced autophagy by suppressing mTOR signaling pathway, which however could be significantly inhibited by baicalin. Baicalin could suppress the expression of Atg5-Atg12 complex and LC3-II, and attenuate autophagy induced by starvation. Thus, the inhibition of autophagy induced by virus may account for the antiviral activities of baicalin against H3N2. Autophagy may be a potential marker in developing novel anti-influenza drugs.

Baicalin, a component of Scutellaria baicalensis, alleviates anorexia and inhibits skeletal muscle atrophy in experimental cancer cachexia

Inflammatory responses are key contributors to cancer cachexia and foster a complex cascade of biological outcomes. Baicalin is a natural compound derived from Scutellaria baicalensis that possesses anti-inflammatory properties in many diseases; therefore, the aim of this study was to verify whether baicalin could ameliorate cachexia in a CT26 adenocarcinoma-induced model. Tumour-bearing and control mice were injected with CT26 adenocarcinoma cells and phosphate-buffered saline (PBS), respectively, and baicalin was administered intraperitoneally for 15 days. During the study, food intake, body weight, major organ weight, gastrocnemius muscle weight, tibialis muscle weight, epididymal fat weight and serum cytokine levels were measured and evaluated. Additionally, the expression of two E3 ubiquitin ligases and NF-κB pathway proteins were detected by Western blot. The total food intake in tumour-bearing mice receiving baicalin from days 1-16, as well as the average food intake on days 10-16, were less than normal but were significantly higher than in vehicle-treated tumour-bearing mice. Loss of tumour-free body mass in vehicle-treated tumour-bearing mice was significantly increased compared with control mice and tumour-bearing mice receiving baicalin. Serum cytokines, including tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6), were lowered in tumour-bearing mice treated with baicalin. Gastrocnemius muscle, epididymal fat, heart and kidney weight were significantly greater in the baicalin treatment groups compared with the vehicle-treated tumour-bearing mice. In addition, the expression of two E3 ubiquitin ligases, as well as phospho-p65, was significantly downregulated, whereas the expression of IκBα was up-regulated in tumour-bearing mice treated with baicalin, as determined by Western blotting. The present study demonstrates that baicalin effectively ameliorates anorexia by inhibiting cytokine expression and prevents skeletal muscle atrophy most likely by inhibiting activation of NF-κB in an experimental cancer cachexia model, suggesting that baicalin represents a promising natural medicine for treating cancer-induced cachexia.