Amurensin H, a Derivative From Resveratrol, Ameliorates Lipopolysaccharide/Cigarette Smoke-Induced Airway Inflammation by Blocking the Syk/NF-κB Pathway

Yiqi Kaimi prescription regulates protein phosphorylation to promote intestinal motility in slow transit constipation

ETHNOPHARMACOLOGICAL RELEVANCE

The clinical efficacy of the Yiqi Kaimi prescription has been confirmed in slow transit constipation. However, the effects and biological mechanism of Yiqi Kaimi prescription are still unclear.

AIMS OF THE STUDY

To identify the effects of Yiqi Kaimi prescription on intestinal motility; To reveal the potential key targets and pathways of Yiqi Kaimi prescription for the treatment of slow transit constipation.

MATERIALS AND METHODS

The effects of Yiqi Kaimi prescription on slow transit constipation were investigated in a mouse model. The terminal ink propulsion experiment and fecal indocyanine green imaging was used to measure the intestinal transit time. Protein phosphorylation changes in colon tissues treated with Yiqi Kaimi prescription were detected using a Phospho Explorer antibody microarray. Bioinformatic analyses were performed using the Database for Annotation Visualization and Integrated Discovery (DAVID) and the Search Tool for the Retrieval of Interacting Genes (STRING). Western blot analysis and immunohistochemistry confirmed the observed changes in phosphorylation.

RESULT

s: Yiqi Kaimi prescription significantly increased the intestinal transit rate (P < 0.05 vs. model) and reduced the time to first discharge of feces containing fecal indocyanine green imaging in mice (P < 0.05 vs. model). The administration of Yiqi Kaimi prescription induced phosphorylation changes in 41 proteins, with 9 upregulated proteins and 32 downregulated proteins. Functional classification of the phosphorylated proteins with DAVID revealed that the critical biological processes included tyrosine protein kinases, positive regulation of calcium-mediated signaling and response to muscle stretch. The phosphorylation of the spleen tyrosine kinase (SYK) at Tyr348 increased 2.19-fold, which was the most significant change. The phosphorylation level of the transcription factor p65 (RELA) at Thr505 was decreased 0.57-fold. SYK was a hub protein in the protein-protein interaction network and SYK and RELA formed the core of the secondary subnetwork. The key protein phosphorylation after treatment with Yiqi Kaimi prescription were verified by Western blot analysis and immunohistochemistry.

CONCLUSION

Yiqi Kaimi prescription significantly enhanced intestinal motility. This effect was attributed to alterations in the phosphorylation levels of various target proteins. The observed changes in protein phosphorylation, including SYK and RELA, may serve as crucial factors in the treatment of slow transit constipation.

Therapeutic Effects of Lifei Decoction in a Murine Model of COPD Induced by LPS and Cigarette Smoke

Introduction

The Lifei Decoction (LD) is a commonly utilized Chinese medicine for the treatment of sepsis and bronchial inflammation. However, its therapeutic potential in chronic obstructive pulmonary disease (COPD) remains unknown. Therefore, the objective of this study was to investigate the therapeutic efficacy and underlying mechanism of LD in a mouse model of COPD induced by cigarette smoke (CS) combined with lipopolysaccharide (LPS).

Methods

Hematoxylin-eosin (H&E) staining was employed to observe the pathological alterations in lung tissue, while ELISA was utilized for the detection of levels of inflammatory factors in both lung tissue and bronchoalveolar lavage fluid (BALF). Additionally, Western blot analysis was conducted to assess the expression of p-NF-κB, GDF11, ZO-1, and Occludin-1 proteins. The changes in intestinal flora were evaluated using the viable bacteria count method.

Results

The administration of LD demonstrates significant efficacy in mitigating pulmonary tissue damage in a murine model, while concurrently inhibiting the activation of the inflammatory pathway NF-κB to attenuate the levels of pro-inflammatory factors. Moreover, LD exhibits the capacity to enhance the expression of intestinal functional proteins ZO-1 and Occludin-1, thereby rectifying dysbiosis within the gut microbiota.

Conclusion

The LD shows great promise as a potential treatment for COPD.

Stilbenes, a Versatile Class of Natural Metabolites for Inflammation-An Overview

Stilbenes are polyphenolic allelochemicals synthesized by plants, especially grapes, peanuts, rhubarb, berries, etc., to defend themselves under stressful conditions. They are now exploited in medicine for their antioxidant, anti-proliferative and anti-inflammatory properties. Inflammation is the immune system's response to invading bacteria, toxic chemicals or even nutrient-deprived conditions. It is characterized by the release of cytokines which can wreak havoc on healthy tissues, worsening the disease condition. Stilbenes modulate NF-κB, MAPK and JAK/STAT pathways, and reduce the transcription of inflammatory factors which result in maintenance of homeostatic conditions. Resveratrol, the most studied stilbene, lowers the Michaelis constant of SIRT1, and occupies the substrate binding pocket. Gigantol interferes with the complement system. Besides these, oxyresveratrol, pterostilbene, polydatin, viniferins, etc., are front runners as drug candidates due to their diverse effects from different functional groups that affect bioavailability and molecular interactions. However, they each have different thresholds for toxicity to various cells of the human body, and thus a careful review of their properties must be conducted. In animal models of autoinflammatory diseases, the mode of application of stilbenes is important to their absorption and curative effects, as seen with topical and microemulsion gel methods. This review covers the diversity seen among stilbenes in the plant kingdom and their mechanism of action on the different inflammatory pathways. In detail, macrophages' contribution to inflamed conditions in the liver, the cardiac, connective and neural tissues, in the nephrons, intestine, lungs and in myriad other body cells is explored, along with detailed explanation on how stilbenes alleviate the symptoms specific to body site. A section on the bioavailability of stilbenes is included for understanding the limitations of the natural compounds as directly used drugs due to their rapid metabolism. Current delivery mechanisms include sulphonamides, or using specially designed synthetic drugs. It is hoped that further research may be fueled by this comprehensive work that makes a compelling argument for the exploitation of these compounds in medicine.

Bioinformatic Analysis and Cellular Assays Identify Substance P Influencing Th17/Treg Differentiation via the MyD88 Pathway as a Potential Contributor to the Progression of Asthma and Allergic Rhinitis

Objective

This study is aimed at investigating the role of substance P (SP) in the development of asthma.

Methods

The Gene Expression Omnibus (GEO) database was used to characterize SP expression in allergic rhinitis (AR) and asthma. Peripheral blood was collected from patients with asthma or AR. The expression of relevant cytokines and neuropeptides was measured. Enzyme-linked immunosorbent assay (ELISA) was also performed. The mast cell line LAD2 and the lung bronchial epithelial cell line BEAS-2B were treated with different concentrations of SP concentration. Then, the qRT-PCR method was used to determine the mRNA expression. Furthermore, p38 and p65 and their associated phosphorylated proteins (p-p38 and p-p65) were further validated by western blotting.

Result

Clinical and GSE75011 data analysis suggested that MyD88 expression was upregulated in AR and asthma. Through the gene set variation analysis (GSVA), MyD88-related pathways were noticed and further investigated. ELISA results suggested that the SP expression was significantly increased in AR and asthma and IL-10 expression was decreased, whereas the expression of IL-6, IL-17A, IL-23, and TGF-β expressions increased. The mast cell line LAD2 was treated with different SP concentrations, and ELISA results showed that the expression of IL-6, IL-17A, IL-23, and TGF-β in the cell supernatant gradually increased with increasing SP concentrations, whereas that of IL-10 decreased. The lung bronchial epithelial cell line BEAS-2B was treated with different SP concentrations, and the expression of myeloid differentiation factor 88 (MyD88) and its related proteins was elevated. The expression of p38 and p-p38 proteins was elevated after SP treatment, and their expression levels elevated as SP concentrations increased. Finally, MyD88 expression at the single-cell level was also demonstrated.

Conclusion

SP may affect the cytokine expression through the MyD88 pathway, thereby influencing Th17/Treg differentiation and eventually participating in the pathological process of asthma and AR. There are many pathological similarities between allergic rhinitis (AR) and bronchial asthma. In the present study, SP was found to possibly activate downstream inflammatory signaling pathways via MyD88, thereby affecting Th17/Treg differentiation and ultimately participating in the pathological process of asthma and AR.

Perilla Leaf Extract (PLE) Attenuates COPD Airway Inflammation via the TLR4/Syk/PKC/NF-κB Pathway In Vivo and In Vitro

Chronic obstructive pulmonary disease (COPD) is a complex and heterogeneous disease characterized by persistent airflow limitation but still lacking effective treatments. Perilla frutescens (L.) Britt., an important traditional medicinal plant with excellent antioxidant and anti-inflammatory properties, is widely used for the treatment of respiratory disease in China. However, its protective activity and mechanism against COPD airway inflammation have not been fully studied. Here, the anti-inflammatory effects of the PLE were investigated, and its underlying mechanisms were then elucidated. The presented results suggested a notable effect of the PLE on airway inflammation of COPD, by significantly ameliorating inflammatory cell infiltration in lung tissue, lessening leukocytes (lymphocytes, neutrophils, and macrophages) and inflammatory mediators (interleukin 4 (IL-4), IL-6, IL-17A, interferon γ (IFN-γ), and tumor necrosis factor α (TNF-α)) in the bronchoalveolar lavage fluid (BALF) of cigarette smoke (CS)/lipopolysaccharide (LPS)-induced COPD mice in vivo and inhibiting the production of inflammatory factors (nitric oxide (NO), IL-6, and TNF-α) and intracellular reactive oxygen species (ROS) in LPS-stimulated RAW264.7 cells in vitro. For further extent, PLE treatment significantly suppressed the expression and phosphorylation of TLR4, Syk, PKC, and NF-κB p65 in vivo and their mRNA in vitro. Subsequently, by co-treating with their inhibitors in vitro, its potential mechanism via TLR4/Syk/PKC/NF-κB p65 signals was disclosed. In summary, the obtained results indicated a noteworthy effective activity of the PLE on COPD inflammation, and partly, the TLR4/Syk/PKC/NF-κB p65 axis might be the potential mechanism.

Syk-Targeted, a New 3-Arylbenzofuran Derivative EAPP-2 Blocks Airway Inflammation of Asthma-COPD Overlap in vivo and in vitro

Introduction

Asthma–chronic obstructive pulmonary (COPD) overlap (ACO) coexists with asthma and COPD syndrome characteristics, with more frequent exacerbations, heavier disease burden, higher medical utilization, and even lower quality of life. However, the ACO standard medications supported by evidence-based medicine have not yet appeared.

Methods

By using an ACO mouse model established previously and LPS-stimulated RAW264.7 macrophages in vitro, a potential therapeutic candidate, EAPP-2, was screened from derivatives of 3-arylbenzofuran, and its effect and mechanism on ACO inflammation were evaluated.

Results

EAPP-2 significantly alleviated airway inflammation in ACO mice and also inhibited the inflammatory reactions in LPS-induced RAW264.7 macrophages in vitro. Furthermore, EAPP-2 significantly inhibited the expression and phosphorylation of spleen tyrosine kinase (Syk), a common target regulating both eosinophils and neutrophils inflammation. In addition to this, EAPP-2 significantly down-regulates the expression of NF-κB, p-NF-κB, and NLRP3 in vivo and in vitro. Moreover, by using specific inhibitors in vitro, it was validated that EAPP-2 targeted on Syk and then regulated its downstream NF-κB and NLRP3.

Conclusion

EAPP-2 is shown to be a potentially useful therapeutic candidate for ACO, and its mechanism is at least partially achieved by targeting on Syk and then inhibiting NF-κB or NLRP3. Moreover, this study suggests that Syk may be a potentially effective target for ACO therapy.

Treatment of chronic airway diseases using nutraceuticals: Mechanistic insight

Respiratory diseases, both acute and chronic, are reported to be the leading cause of morbidity and mortality, affecting millions of people globally, leading to high socio-economic burden for the society in the recent decades. Chronic inflammation and decline in lung function are the common symptoms of respiratory diseases. The current treatment strategies revolve around using appropriate anti-inflammatory agents and bronchodilators. A range of anti-inflammatory agents and bronchodilators are currently available in the market; however, the usage of such medications is limited due to the potential for various adverse effects. To cope with this issue, researchers have been exploring various novel, alternative therapeutic strategies that are safe and effective to treat respiratory diseases. Several studies have been reported on the possible links between food and food-derived products in combating various chronic inflammatory diseases. Nutraceuticals are examples of such food-derived products which are gaining much interest in terms of its usage for the well-being and better human health. As a consequence, intensive research is currently aimed at identifying novel nutraceuticals, and there is an emerging notion that nutraceuticals can have a positive impact in various respiratory diseases. In this review, we discuss the efficacy of nutraceuticals in altering the various cellular and molecular mechanisms involved in mitigating the symptoms of respiratory diseases.

Brusatol Derivative-34 Attenuates Allergic Airway Inflammation Via Inhibition of the Spleen Tyrosine Kinase Pathway

Brusatol derivative-34 (Bru-34), a derivative of brusatol, has been shown significantly anti-inflammatory activity in mice in our previously work. However, to our knowledge, there were very limited studies on how Bru-34 affected airway inflammation. Thus, in this present study, the effects and potential mechanisms of Bru-34 on allergic airway inflammation were examined both in vivo and in vitro. The results showed that Bru-34 attenuated the allergic airway inflammation in mice, with significant decreasing of the inflammatory cells and mediators in bronchoalveolar lavage fluids and attenuation of the histopathological alterations in the lung tissues. In addition, Bru-34 significantly inhibited the release of inflammatory cytokines in antigen induced rat basophilic leukemia -2H3 (RBL-2H3) cells. What’s more, Bru-34 significantly decreased the expression of spleen tyrosine kinase (Syk), p-Syk, cytoplasmic phospholipase A2 (cPLA2), p-cPLA2, nuclear factor-κB (NF-κB) and p-NF-κB both in allergic mice lung tissue and antigen induced RBL-2H3 cells. Furthermore, the collaborative effects of Bru-34 with inhibitors against Syk, cPLA2, and NF-κB, showed that Syk was an important target of Bru-34, and cPLA2 and NF-κB played important roles in the coordinated inflammatory response. In conclusion, Bru-34 could significantly modulate the allergic airway inflammation, and its potential mechanism was revealed at least partially via down-regulating of Syk-cPLA2 -NF-κB signaling.

Cigarette smoke extract induces pyroptosis in human bronchial epithelial cells through the ROS/NLRP3/caspase-1 pathway

AIMS

Pyroptosis and inflammation are involved in the development of chronic obstructive pulmonary disease (COPD). However, the cigarette smoke-mediated mechanism of COPD remains unclear. In this study, we aimed to investigate the role of nucleotide-binding domain-like receptor protein-3 (NLRP3) inflammasome-mediated pyroptosis in the death of human bronchial epithelial (HBE) cells after cigarette smoke extract (CSE) exposure.

MAIN METHODS

The protein level of NLRP3 in lung tissue was measured after cigarette smoke exposure in vivo. In vitro, HBE cells were treated with CSE. Subsequently, the activity of caspase-1, lactate dehydrogenase (LDH) release, release of interleukin (IL)-1β and NLRP3 expression levels were measured. The involvement of reactive oxygen species (ROS) was also explored.

KEY FINDINGS

After exposure to CSE, increased release of LDH, the transcriptional and translational upregulation of NLRP3, the caspase-1 activity levels, and enhanced IL-1β and IL-18 release were observed in 16HBE cells. In addition, NLRP3 was required to activate the caspase-1. Our results suggested that pre-stimulated of 16HBE with a caspase-1 inhibitor, or using NLRP3 siRNA to silence NLRP3 expression, also caused the decrease of IL-1β release and pyroptosis.

SIGNIFICANCES

CSE induced inflammation and contributed to pyroptosis through the ROS/NLRP3/caspase-1 pathway in 16HBE cells. The NLRP3 inflammasome participates in CSE-induced HBE cell damage and pyroptosis, which could provide new insights into COPD.

Multiple Components Rapidly Screened from Perilla Leaves Attenuate Asthma Airway Inflammation by Synergistic Targeting on Syk

Background

Perilla frutescens (L.) Britt., a classic medicinal plant, has been demonstrated to have anti-inflammatory and anti-allergic effects in asthma. Perilla leaves extract (PLE) exerted significant therapeutic effect against allergic asthma inflammation through Syk inhibition. But the active chemical ingredients from PLE are complex and unclear, it is difficult to fully elucidate its pharmacological mechanisms.

Methods

A method was established for rapid screening and characterization of active ingredients from PLE that targeted Syk, with which three potential active ingredients were identified. By using OVA-induced allergic asthma mouse model in vivo, OVA-induced human PBMCs inflammation model and DNP-IgE/BSA-induced RBL-2H3 cells model in vitro, the effects and mechanisms of PLE and its active components were evaluated.

Results

Using Syk-affinity screening method, roseoside (RosS), vicenin-2 (Vic-2) and rosmarinic acid (RosA) were identified from PLE. In vitro, PLE and its ingredients showed significant inhibitory activities against Syk, with their mixture (Mix, prepared by RosS, Vic-2 and RosA in accordance with their ratio in Syk-conjugated beads bound fraction) showing a stronger inhibitory activity. RosS, Vic-2 and RosA also showed significant effects on allergic asthma, and a synergistic effect of Mix was observed. Moreover, treatment with PLE, RosS, Vic-2, RosA, and Mix significantly inhibited the expression and phosphorylation of Syk, PKC, NF-κB p65, and cPLA₂ in allergic mice lung tissue and in RBL-2H3 cells.

Conclusion

PLE may alleviate allergic airway inflammation partly through the multiple components synergistic targeting on Syk and its downstream inflammatory pathway.

Berberine Administration in Treatment of Colitis: A Review

Berberine (Brb) is one of the well-known naturally occurring compounds exclusively found in Berberis vulgaris and other members of this family, such as Berberis aristata, Berberis aroatica, and Berberis aquifolium. This plant-derived natural compound has a variety of therapeutic impacts, including anti-oxidant, anti-inflammatory, anti-diabetic, and anti-tumor. Multiple studies have demonstrated that Brb has great anti-inflammatory activity and is capable of reducing the levels of proinflammatory cytokines, while it enhances the concentrations of anti-inflammatory cytokines, making it suitable for the treatment of inflammatory disorders. Colitis is an inflammatory bowel disease with chronic nature. Several factors are involved in the development of colitis and it appears that inflammation and oxidative stress are the most important ones. With respect to the anti-inflammatory and antioxidant effects of Brb, its administration seems to be beneficial in the treatment of colitis. In the present review, the protective effects of Brb in colitis treatment and its impact on molecular pathways are discussed.

BAY61-3606 protects kidney from acute ischemia/reperfusion injury through inhibiting spleen tyrosine kinase and suppressing inflammatory macrophage response

Acute kidney injury (AKI) is a highly prevalent clinical syndrome with high mortality and morbidity. Previous studies indicated that inflammation promotes tubular damage and plays a key role in AKI progress. Spleen tyrosine kinase (Syk) has been linked to macrophage-related inflammation in AKI. Up to date, however, no Syk-targeted therapy for AKI has been reported. In this study, we employed both cell model of LPS-induced bone marrow-derived macrophage (BMDM) and mouse model of ischemia/reperfusion injury (IRI)-induced AKI to evaluate the effects of a Syk inhibitor, BAY61-3606 (BAY), on macrophage inflammation in vitro and protection of kidney from AKI in vivo. The expression and secretion of inflammatory cytokines, both in vitro and in vivo, were significantly inhibited even back to normal levels by BAY. The upregulated serum creatinine and blood urea nitrogen levels in the AKI mice were significantly reduced after administration of BAY, implicating a protective effect of BAY on kidneys against IRI. Further analyses from Western blot, immunofluorescence staining and flow cytometry revealed that BAY inhibited the Mincle/Syk/NF-κB signaling circuit and reduced the inflammatory response. BAY also inhibited the reactive oxygen species (ROS), which further decreased the formation of inflammasome and suppressed the mature of IL-1β and IL-18. Notably, these inhibitory effects of BAY on inflammation and inflammasome in BMDM were significantly reversed by Mincle ligand, trehalose-6,6-dibehenate. In summary, these findings provided compelling evidence that BAY may be an efficient inhibitor of the Mincle/Syk/NF-κB signaling circuit and ROS-induced inflammasome, which may help to develop Syk-inhibitors as novel therapeutic agents for AKI.

3,4,5-Trihydroxycinnamic acid exerts a protective effect on pulmonary inflammation in an experimental animal model of COPD

3,4,5-Trihydroxycinnamic acid (THCA), a derivative of hydroxycinnamic acid, has been reported to exert anti-inflammatory and antioxidant activities. However, its anti-inflammatory effects in chronic obstructive pulmonary disease (COPD) have not yet been elucidated. Therefore, we explored the protective effects of THCA on pulmonary inflammation in an experimental COPD model elicited by cigarette smoke (CS) and lipopolysaccharide (LPS). Oral administration of THCA significantly inhibited the activity of elastase, the release of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1), myeloperoxidase (MPO) and the numbers of neutrophils and macrophages in the bronchoalveolar lavage fluid (BALF) of experimental COPD mice. THCA also exerted inhibitory effects on the recruitment of inflammatory cells, the levels of PAS positive cells and cAMP-response-element-binding protein (CREB) activation, and the expression of phosphodiesterase 4 (PDE4) in the lungs of experimental COPD mice. In addition, THCA exerted a regulatory effect on the activation of p38, ERK and nuclear factor-κB (NF-κB) in the lungs of experimental COPD mice. THCA also significantly upregulated the expression of NAD(P)H dehydrogenase (quinone 1) 1 (NQO1) and the activation of nuclear factor erythroid-derived 2-related factor 2 (Nrf2) in the lungs of mice. Furthermore, THC restored the reduction of NAD-dependent protein deacetylase sirtuin-1 (SIRT1) in the lungs of experimental COPD mice. In phorbol myristate acetate (PMA)-stimulated A549 or H292 airway epithelial cells, pretreatment of THCA dose-dependently inhibited the generation of IL-6. THCA also led to increased NQO1 expression in H292 cells. Collectively, these protective effects of antioxidant THCA were notably excellent and are thought to be associated with the downregulation of MAPK (partial)/NF-κB signaling and upregulation of NQO1 and SIRT1 expression.

Triterpene Acids of Loquat Leaf Improve Inflammation in Cigarette Smoking Induced COPD by Regulating AMPK/Nrf2 and NFκB Pathways

Cigarette smoking (CS) is believed to be an important inducement in the pathological development of chronic obstructive pulmonary disease (COPD), a progressive lung disease. Loquat is an Asian evergreen tree commonly cultivated for its fruit. Its leaf has long been used as an important material for both functional and medicinal applications in the treatment of lung disease in China and Japan. As the principal functional components of loquat leaf, triterpene acids (TAs) have shown notable anti-inflammatory activity. However, their protective activity and underlying action of mechanism on CS-induced COPD inflammation are not yet well understood. In the present study, male C57BL/6 mice were challenged with CS for 12 weeks, and from the seventh week of CS exposure, mice were fed with TAs (50 and 100 mg/kg) for 6 weeks to figure out the therapeutic effect and molecular mechanism of TAs in CS-induced COPD inflammation. The results demonstrate that TA suppressed the lung histological changes in CS-exposed mice, as evidenced by the diminished generation of pro-inflammatory cytokines, including interleukin 1β (IL-1β), IL-2, IL-6, and tumor necrosis factor α (TNF-α). Moreover, TA treatment significantly inhibited the malondialdehyde (MDA) level and increased superoxide dismutase (SOD) activity. In addition, TAs increased the phosphorylation of AMP-activated protein kinase (AMPK) and nuclear factor erythroid-2-related factor-2 (Nrf2) expression level, while inhibiting phosphorylation of nuclear factor kappa B (NFκB) and inducible nitric oxide synthase (iNOS) expression in CS-induced COPD. In summary, our study reveals a protective effect and putative mechanism of TA action involving the inhibition of inflammation by regulating AMPK/Nrf2 and NFκB pathways. Our findings suggest that TAs could be considered as a promising functional material for treating CS-induced COPD.

Chondroprotective and anti-inflammatory effects of amurensin H by regulating TLR4/Syk/NF-κB signals

The low-grade, chronic inflammation initiated by TLR4-triggered innate immune responses has a central role on early osteoarthritis. Amurensin H is a resveratrol dimer with anti-inflammatory and anti-apoptotic effects, while its effects on TLR-4 signals to inhibit osteoarthritis are still unclear. In the present study, treatment with amurensin H for 2 weeks in monosodium iodoacetate-induced mice significantly slows down cartilage degeneration and inflammation using macroscopic evaluation, haematoxylin and eosin (HE) staining and micro-magnetic resonance imaging. In IL-1β-stimulated rat chondrocytes, amurensin H suppresses the production of inflammatory mediators including nitric oxide, IL-6, IL-17, PGE2 and TNF-α using Greiss and ELISA assay. Amurensin H inhibits matrix degradation via decreasing levels of MMP-9 and MMP-13 using Western blot assay, promotes synthesis of type II collagen and glycosaminoglycan using immunostaining and safranin O staining, respectively. Amurensin H inhibits intracellular and mitochondrial reactive oxygen species (ROS) generation, and mitochondrial membrane depolarization using DCFH-DA, MitoSOX Red and JC-1 assay as well. IL-1β stimulates TLR4 activation and Syk phosphorylation in chondrocytes, while amurensin H inhibits TLR4/Syk signals and downstream p65 phosphorylation and translocation in a time and dose-dependent manner. Together, these results suggest that amurensin H exerts chondroprotective effects by attenuating oxidative stress, inflammation and matrix degradation via the TLR4/Syk/NF-κB pathway.