Fisetin Suppresses Macrophage-Mediated Inflammatory Responses by Blockade of Src and Syk

Natural bioactive compounds-The promising candidates for the treatment of intestinal failure-associated liver disease

Parenteral nutrition (PN) is a life-saving procedure conducted to maintain a proper nutritional state in patients with severe intestinal failure who cannot be fed orally. A serious complication of PN therapy is liver failure, known as intestinal failure-associated liver disease (IFALD). The pathogenesis of IFALD is multifactorial and includes inhibition of the farnesoid X receptor (FXR) by PN components, bacteria translocation from impaired intestines, and intravenous line-associated bloodstream infection. Currently, the most frequently researched therapeutic option for IFALD is using lipid emulsions based on soy or fish oil and, therefore, free from phytosterols known as FXR antagonists. Nevertheless, the potential side effects of the lack of soybean oil delivery seem to outweigh the benefits, especially in the pediatric population. PN admixture provides all the necessary nutrients; however, it is deprived of exogenous natural bioactive compounds (NBCs) of plant origin, such as polyphenols, characterized by health-promoting properties. Among them, many substances have already been known to demonstrate the hepatoprotective effect in various liver diseases. Therefore, searching for new therapeutic options for IFALD among NBCs seems reasonable and potentially successful. This review summarizes the recent research on polyphenols and their use in treating various liver diseases, especially metabolic dysfunction-associated steatotic liver diseases (MASLD). Furthermore, based on scientific reports, we have described the molecular mechanism of action of selected NBCs that exert hepatoprotective properties. We also summarized the current knowledge on IFALD pathogenesis, described therapeutic options undergoing clinical trials, and presented the future perspective of the potential use of NBCs in PN therapy.

Fisetin is a selective adenosine triphosphate-competitive inhibitor for mitogen-activated protein kinase kinase 4 to inhibit lipopolysaccharide-stimulated inflammation

The mitogen-activated protein kinase kinase 4 (MKK4), a member of the MAP kinase kinase family, directly phosphorylates and activates the c-Jun NH2-terminal kinases (JNK), in response to proinflammatory cytokines and cellular stresses. Regulation of the MKK4 activity is considered to be a novel approach for the prevention and treatment of inflammation. The aim of this study was to identify whether fisetin, a potential anti-inflammatory compound, targets MKK4-JNK cascade to inhibit lipopolysaccharide (LPS)-stimulated inflammatory response. RAW264 macrophage pretreated with fisetin following LPS stimulation was used as a cell model to investigate the transactivation and expression of related-inflammatory genes by transient transfection assay, electrophoretic mobility shift assay (EMSA), or enzyme-linked immunosorbent assay (ELISA), and cellular signaling as well as binding of related-signal proteins by Western blot, pull-down assay and kinase assay, and molecular modeling. The transactivation and expression of cyclooxygenase-2 (COX-2) gene as well as prostaglandin E2 (PGE2) secretion induced by LPS were inhibited by fisetin in a dose-dependent manner. Signaling transduction analysis demonstrated that fisetin selectively inhibited MKK4-JNK1/2 signaling to suppress the phosphorylation of transcription factor AP-1 without affecting the NF-κB and Jak2-Stat3 signaling as well as the phosphorylation of Src, Syk, and TAK1. Furthermore, in vitro and ex vivo pull-down assay using cell lysate or purified protein demonstrated that fisetin could bind directly to MKK4. Molecular modeling using the Molecular Operating Environment™ software indicated that fisetin docked into the ATP-binding pocket of MKK4 with a binding energy of -71.75 kcal/mol and formed a 1.70 Å hydrogen bound with Asp247 residue of MKK4. The IC50 of fisetin against MKK4 was estimated as 2.899 μM in the kinase assay, and the ATP-competitive effect was confirmed by ATP titration. Taken together, our data revealed that fisetin is a potent selective ATP-competitive MKK4 inhibitor to suppress MKK4-JNK1/2-AP-1 cascade for inhibiting LPS-induced inflammation.

Hinesol attenuates DSS-induced ulcerative colitis through the suppression of Src-mediated NF-κB and chemokine signaling pathway

As a common inflammatory bowel disease, ulcerative colitis (UC) is featured with inflammation, oxidative damage, and the impairment of intestinal mucosal barrier, which bring threat to patients' quality of live. Hinesol, derived from Atractylodes lancea, is a unique sesquiterpenoid. Our study proposed to survey the effects and mechanism of hinesol in UC. UC mouse model was constructed using dextran sulfate sodium (DSS). Lipopolysaccharide (LPS) was applied for RAW264.7 cells stimulation to construct cell inflammatory model. The changes of disease activity index (DAI), body weight, colon length, and intestinal pathology in mice were analyzed to estimate the severity of colitis. Enzyme-linked immunosorbent assay was applied to check the changes of interleukin (IL)-1β, IL-18, IL-6, and tumor necrosis factor (TNF)-α. The levels of myeloperoxidase (MPO), superoxide dismutase (SOD), glutathione peroxidase (GSH-px), catalase (CAT), and malondialdehyde (MDA) were estimated by corresponding reagent kit. The changes of phosphorylated (p)-NF-κB P65, and p-IκBα, ZO-1, Occludin, Claudin-1, Src, XCL1, CCL2, and CXCL16 protein were examined using western blot. Flow cytometry and cell counting kit-8 assay were utilized for assessment of cell apoptosis and viability. We found that DSS reduced mice body weight, increased DAI, shorten colon length, and led to severe enteric mucosal injury, while hinesol improved the above symptoms induced by DSS. In DSS mice, hinesol raised the levels of ZO-1, Occludin, Claudin-1, SOD, GSH-px, and CAT and decreased the levels of TNF-α, IL-18, IL-1β, IL-6, MPO, and MDA. Additionally, in DSS mice and LPS-stimulated RAW264.7 cells, hinesol inhibited the high expression of Src, XCL1, CCL2, CXCL16, p-NF-κB P65, and p-IκBα. The molecular docking showed that there was a good interaction between hinesol and Src. Moreover, in LPS-stimulated RAW 264.7 cells, Src overexpression partially reversed the inhibition of hinesol on cell apoptosis, pro-inflammatory factors, and oxidative stress. In conclusion, hinesol alleviated DSS-induced colitis, which might have a bearing on the inhibition of Src-mediated NF-κB and chemokine signaling pathway.

The natural polyphenol fisetin in atherosclerosis prevention: a mechanistic review

The incidence and mortality rate of atherosclerotic cardiovascular disease (ASCVD) is increasing yearly worldwide. Recently, a growing body of evidence has unveiled the anti-atherosclerotic properties of fisetin, a natural polyphenol compound. In this article, we reviewed the pharmacologic actions of fisetin on experimental atherosclerosis and its protective effects on disease-relevant cell types such as endothelial cells, macrophages, vascular smooth muscle cells, and platelets. Based on its profound cardiovascular actions, fisetin holds potential for clinical translation and could be developed as a potential therapeutic option for atherosclerosis and its related complications. Large-scale randomized clinical trials are warranted to ascertain the safety and efficacy of fisetin in patients with or high risk for ASCVD.

Efficacy of FRO on Acne Vulgaris Pathogenesis

Acne vulgaris is a common skin disease characterized by increased sebum production, inflammation, and Cutibacterium acnes (CA: formerly Propionibacterium acnes) hyperproliferation in pilosebaceous follicles. This study evaluated the efficacy of FRO, a formula composed of fermented Rhus verniciflua Stokes and Orostachys japonicus, against acne pathogenesis via antimicrobial assessment and an in vitro analysis. Stimulated model cells treated with hormones, CA, or lipopolysaccharide (LPS) were designed based on the characteristics of acne pathogenesis, including inflammation and sebum hypersecretion. High-performance liquid chromatography, disc diffusion, MTS, and western blotting assays were used to examine potential anti-acne effects. FRO was determined to contain phenolics such as gallic acid, fisetin, quercetin, and kaempferol. FRO exerted antimicrobial activity against CA and inhibited reactive oxygen species production that was otherwise increased by LPS or CA in HaCaT cells. Additionally, FRO exerted anti-inflammatory effects by inhibiting iNOS, TNF-α, IL-6, p-STAT-3, and p-NF-κB, which were previously upregulated by LPS or CA in THP-1 and HaCaT cells. FRO inhibited lipogenesis induced by steroid hormones and CA by decreasing FAS and SREBP-1 levels in sebocytes. Additionally, FRO down-regulated the androgen receptor, 5α-reductase, SREBP-1, and FAS levels, which were upregulated by steroid hormone in LNCaP cells. Taken together, our findings suggest that FRO alleviates acne by inhibiting the growth of CA, inflammation, and excess sebum and could be used for functional cosmetics or acne treatments.

Plausibility of natural immunomodulators in the treatment of COVID-19-A comprehensive analysis and future recommendations

The COVID-19 pandemic has inflicted millions of deaths worldwide. Despite the availability of several vaccines and some special drugs approved for emergency use to prevent or treat this disease still, there is a huge concern regarding their effectiveness, adverse effects, and most importantly, their efficacy against the new variants. A cascade of immune-inflammatory responses is involved with the pathogenesis and severe complications with COVID-19. People with dysfunctional and compromised immune systems display severe complications, including acute respiratory distress syndrome, sepsis, multiple organ failure etc., when they get infected with the SARS-CoV-2 virus. Plant-derived natural immune-suppressant compounds, such as resveratrol, quercetin, curcumin, berberine, luteolin, etc., have been reported to inhibit pro-inflammatory cytokines and chemokines. Therefore, natural products with immunomodulatory and anti-inflammatory potential could be plausible targets to treat this contagious disease. This review aims to delineate the clinical trials status and outcomes of natural compounds with immunomodulatory potential in COVID-19 patients along with the outcomes of their in-vivo studies. In clinical trials several natural immunomodulators resulted in significant improvement of COVID-19 patients by diminishing COVID-19 symptoms such as fever, cough, sore throat, and breathlessness. Most importantly, they reduced the duration of hospitalization and the need for supplemental oxygen therapy, improved clinical outcomes in patients with COVID-19, especially weakness, and eliminated acute lung injury and acute respiratory distress syndrome. This paper also discusses many potent natural immunomodulators yet to undergo clinical trials. In-vivo studies with natural immunomodulators demonstrated reduction of a wide range of proinflammatory cytokines. Natural immunomodulators that were found effective, safe, and well tolerated in small-scale clinical trials are warranted to undergo large-scale trials to be used as drugs to treat COVID-19 infections. Alongside, compounds yet to test clinically must undergo clinical trials to find their effectiveness and safety in the treatment of COVID-19 patients.

In vitro anti-cancer effects of beauvericin through inhibition of actin polymerization and Src phosphorylation

BACKGROUND

Beauvericin (BEA) is a depsipeptide with antimicrobial, anti-inflammatory, and anti-cancer activities isolated from Beauveria bassiana. However, little is understood on its anti-cancer activities and mechanism.

PURPOSE

Aim of this study was to explore the anti-cancer activity of BEA and its underlying molecular mechanism to provide a theoretical basis for its role as a candidate natural drug in cancer diseases.

STUDY DESIGN

Various cancer cells such as C6 glioma, U251, MDA-MB-231, HeLa, HCT-15, LoVo cells, and HEK293T cells were used to the anti-cancer activity of BEA.

METHODS

To evaluate the anti-cancer activity of BEA, cell viability test (MTT assay), morphological change check, confocal microscopy, actin polymerization assay, flow cytometry, and Western blotting analysis. To check the target enzyme of BEA, overexpression and site-directed mutagenesis was employed.

RESULTS

BEA inhibited the viability of cancer cells including C6, MDA-MB-231, HeLa, HCT-15, LoVo, and U251 cells. Treatment of BEA in C6 glioma cells induced cell membrane blebbing and apoptosis. Caspase-3 and -9 were dose-dependently activated by BEA, and the mRNA expression of Bcl-2 was inhibited by BEA. According to confocal microscopy, actin polymerization and actin-actin interaction were interrupted by BEA in C6 cells. BEA regulated the apoptosis of C6 cells depending on the protein phosphorylation of Src and Signal transducer and activator of transcription (STAT3). Moreover, c-terminal amino acids in Src directly interacted with BEA in C6 cells, and the binding of Src and BEA suppressed the kinase activity of Src.

CONCLUSIONS

These results suggest that BEA may be a critical candidate or substitute drug for cancer treatment via suppression of the Src/STAT3 pathway.

The neuroprotective effects of fisetin, a natural flavonoid in neurodegenerative diseases: Focus on the role of oxidative stress

Oxidative stress (OS) disrupts the chemical integrity of macromolecules and increases the risk of neurodegenerative diseases. Fisetin is a flavonoid that exhibits potent antioxidant properties and protects the cells against OS. We have viewed the NCBI database, PubMed, Science Direct (Elsevier), Springer-Nature, ResearchGate, and Google Scholar databases to search and collect relevant articles during the preparation of this review. The search keywords are OS, neurodegenerative diseases, fisetin, etc. High level of ROS in the brain tissue decreases ATP levels, and mitochondrial membrane potential and induces lipid peroxidation, chronic inflammation, DNA damage, and apoptosis. The subsequent results are various neuronal diseases. Fisetin is a polyphenolic compound, commonly present in dietary ingredients. The antioxidant properties of this flavonoid diminish oxidative stress, ROS production, neurotoxicity, neuro-inflammation, and neurological disorders. Moreover, it maintains the redox profiles, and mitochondrial functions and inhibits NO production. At the molecular level, fisetin regulates the activity of PI3K/Akt, Nrf2, NF-κB, protein kinase C, and MAPK pathways to prevent OS, inflammatory response, and cytotoxicity. The antioxidant properties of fisetin protect the neural cells from inflammation and apoptotic degeneration. Thus, it can be used in the prevention of neurodegenerative disorders.

Src Family Kinases: A Potential Therapeutic Target for Acute Kidney Injury

Src family kinases (SFKs) are non-receptor tyrosine kinases and play a key role in regulating signal transduction. The mechanism of SFKs in various tumors has been widely studied, and there are more and more studies on its role in the kidney. Acute kidney injury (AKI) is a disease with complex pathogenesis, including oxidative stress (OS), inflammation, endoplasmic reticulum (ER) stress, autophagy, and apoptosis. In addition, fibrosis has a significant impact on the progression of AKI to developing chronic kidney disease (CKD). The mortality rate of this disease is very high, and there is no effective treatment drug at present. In recent years, some studies have found that SFKs, especially Src, Fyn, and Lyn, are involved in the pathogenesis of AKI. In this paper, the structure, function, and role of SFKs in AKI are discussed. SFKs play a crucial role in the occurrence and development of AKI, making them promising molecular targets for the treatment of AKI.

Potential therapeutic application of biophenols - plants secondary metabolites in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease showed that persistent inflammation in the joints, induces the cartilage destruction, bone erosion, and leukocyte infiltration in the synovium. RA mostly affects the joints of hands, feet, wrists, ankles, and knees. Each year, approximately 20-40 new cases are reported per lac population and the disease affects women more than men. The etiology of RA is still unknown, but many pathways have been identified as potential targets in its pathophysiology, including the PI3K/AKT signaling pathway, NF-κB signaling, Adenosine signaling, Wnt, SYK/BTK, and mTOR signaling pathways. Biophenol, plant secondary metabolite, is considered one of the most abundantly phytoconstituents to have potential anti-inflammatory effects associated with multiple pathways. These indicate that biophenols can be used for its protective effect on the development and symptoms of RA. The current review explores and discusses the role of different biophenols in the treatment of RA disease.

Systems pharmacology-based drug discovery and active mechanism of natural products for coronavirus pneumonia (COVID-19): An example using flavonoids

BACKGROUND

Recently, the value of natural products has been extensively considered because these resources can potentially be applied to prevent and treat coronavirus pneumonia 2019 (COVID-19). However, the discovery of nature drugs is problematic because of their complex composition and active mechanisms.

METHODS

This comprehensive study was performed on flavonoids, which are compounds with anti-inflammatory and antiviral effects, to show drug discovery and active mechanism from natural products in the treatment of COVID-19 via a systems pharmacological model. First, a chemical library of 255 potential flavonoids was constructed. Second, the pharmacodynamic basis and mechanism of action between flavonoids and COVID-19 were explored by constructing a compound-target and target-disease network, targets protein-protein interaction (PPI), MCODE analysis, gene ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment.

RESULTS

In total, 105 active flavonoid components were identified, of which 6 were major candidate compounds (quercetin, epigallocatechin-3-gallate (EGCG), luteolin, fisetin, wogonin, and licochalcone A). 152 associated targets were yielded based on network construction, and 7 family proteins (PTGS, GSK3β, ABC, NOS, EGFR, and IL) were included as central hub targets. Moreover, 528 GO items and 178 KEGG pathways were selected through enrichment of target functions. Lastly, molecular docking demonstrated good stability of the combination of selected flavonoids with 3CL Pro and ACEⅡ.

CONCLUSION

Natural flavonoids could enable resistance against COVID-19 by regulating inflammatory, antiviral, and immune responses, and repairing tissue injury. This study has scientific significance for the selective utilization of natural products, medicinal value enhancement of flavonoids, and drug screening for the treatment of COVID-19 induced by SARS-COV-2.

Medicinal Plants in Cancer Treatment: Contribution of Nuclear Factor-Kappa B (NF-kB) Inhibitors

Nuclear factor-kappa B (NF-κB) is one of the principal inducible proteins that is a predominant transcription factor known to control the gene expression in mammals and plays a pivotal role in regulating cell signalling in the body under certain physiological and pathological conditions. In cancer cells, such as colon, breast, pancreatic, ovarian, melanoma, and lymphoma, the NF-κB pathway has been reported to be active. In cellular proliferation, promoting angiogenesis, invasion, metastasis of tumour cells and blocking apoptosis, the constitutive activity of NF-κB signalling has been reported. Therefore, immense attention has been given to developing drugs targeting NF-κB signalling pathways to treat many types of tumours. They are a desirable therapeutic target for drugs, and many studies concentrated on recognizing compounds. They may be able to reverse or standstill the growth and spread of tumours that selectively interfere with this pathway. Recently, numerous substances derived from plants have been evaluated as possible inhibitors of the NF-κB pathway. These include various compounds, such as flavonoids, lignans, diterpenes, sesquiterpenes, polyphenols, etc. A study supported by folk medicine demonstrated that plant-derived compounds could suppress NF-κB signalling. Taking this into account, the present review revealed the anticancer potential of naturally occurring compounds which have been verified both by inhibiting the NF-κB signalling and suppressing growth and spread of cancer and highlighting their mechanism of NF-κB inhibition.

Dietary Phytochemicals that Can Extend Longevity by Regulation of Metabolism

Diet provides energy and nutrition for human survival, and also provides various joy of taste. Extensive studies have shown that the major components of diet, such as protein, carbohydrate and fat, play important roles in regulating aging and longevity. Whether other dietary ingredients can help prevent aging and extend longevity is a very interesting question. Here based on recent findings, we discussed dietary plant ingredients that can extend longevity by regulation of metabolism, targeting TRP channels, mitophagy, senescence pathways and circadian rhythms. Better understanding of the detailed effects and mechanisms of dietary ingredients on longevity regulation, would be helpful for developing new intervention tools for preventing aging and aging related diseases.

Fisetin, potential flavonoid with multifarious targets for treating neurological disorders: An updated review

Neurodegenerative disorders pose a significant health burden and imprint a debilitative impact on the quality of life. Importantly, aging is intricately intertwined with the progression of these disorders, and their prevalence increases with a rise in the aging population worldwide. In recent times, fisetin emerged as one of the potential miracle molecules to address neurobehavioral and cognitive abnormalities. These effects were attributed to its actions on several macromolecules and multiple molecular mechanisms. Fisetin belongs to a class of flavonoids, which is found abundantly in several fruits and vegetables. Fisetin has manifested several health benefits in preclinical models of neurodegenerative diseases such as Alzheimer's disease, Vascular dementia, and Schizophrenia. Parkinson's disease, Amyotrophic Lateral Sclerosis, Huntington's disease, Stroke, Traumatic Brain Injury (TBI), and age-associated changes. This review aimed to evaluate the potential mechanisms and pharmacological effects of fisetin in treating several neurological diseases. This review also provides comprehensive data on up-to-date recent literature and highlights the various mechanistic pathways pertaining to fisetin's neuroprotective role.

Fisetin Protects HaCaT Human Keratinocytes from Fine Particulate Matter (PM2.5)-Induced Oxidative Stress and Apoptosis by Inhibiting the Endoplasmic Reticulum Stress Response

Fine particulate matter (PM_2.5) originates from the combustion of coal and is found in the exhaust of fumes of diesel vehicles. PM_2.5 readily penetrates the skin via the aryl hydrocarbon receptor, causing skin senescence, inflammatory skin diseases, DNA damage, and carcinogenesis. In this study, we investigated whether fisetin, a bioactive flavonoid, prevents PM_2.5-induced apoptosis in HaCaT human keratinocytes. The results demonstrated that fisetin significantly downregulated PM_2.5-induced apoptosis at concentrations below 10 μM. Fisetin strongly inhibited the production of reactive oxygen species (ROS) and the expression of pro-apoptotic proteins. The PM_2.5-induced apoptosis was associated with the induction of the endoplasmic reticulum (ER) stress response, mediated via the protein kinase R-like ER kinase (PERK)–eukaryotic initiation factor 2α (eIF2α)–activating transcription factor 4 (ATF4)–CCAAT-enhancer-binding protein (C/EBP) homologous protein (CHOP) axis. Additionally, the cytosolic Ca²⁺ levels were markedly increased following exposure to PM_2.5. However, fisetin inhibited the expression of ER stress-related proteins, including 78 kDa glucose-regulated protein (GRP78), phospho-eIF2α, ATF4, and CHOP, and reduced the cytosolic Ca²⁺ levels. These data suggest that fisetin inhibits PM_2.5-induced apoptosis by inhibiting the ER stress response and production of ROS.

Fisetin prevents oxidized low-density lipoproteins induced macrophage foam cell formation

ABSTRACT

Foam cell formation in an important event in atherosclerosis. Fisetin, a bioflavonoid, has long been identified to possess anti-inflammatory, anti-lipidemic and anti-cancerous properties, however its role as a lipid homeostasis regulator in macrophage specifically in presence of metabolic stressors such as oxLDL is not well understood. In this study we have investigated the role of fisetin in preventing oxLDL-induced macrophage FCF. U937-derived macrophages were stimulated with oxLDL with or without fisetin for varied time points and various parameters were assessed including cell viability by MTT assay, ROS by DCFDA assay, lipid accumulation by Oil Red O staining, and expression of NLRP3, Sterol regulatory element binding protein (SREBP)-1 and associated downstream proteins HMG CoA reductase (HMGCR) and fatty acid synthase (FAS) were assessed by RT-qPCR and immunoblotting. Functionality of FAS enzyme was determined using enzyme activity assay. Docking studies were performed to determine in-silico interaction between NLRP3 and fisetin. The results showed that fisetin, up to the dose of 10 µM did not alter cell viability but at the same dose could decrease the accumulation of lipids in macrophages and prevented FCF. Fisetin could also ameliorate and reduce oxLDL-induced upregulation of SREBP-1 and thereby expression of its downstream liposynthesis genes HMGCR and FAS and inhibited ROS-induced NLRP3 inflammasome activation. In conclusion, fisetin could inhibit foam cell formation by blocking oxLDL induced ROS formation and subsequent NLRP3 activation, thereby inhibiting SREBP-1 and its downstream genes including FAS and HMGCR.

Fisetin promotes osteoblast differentiation and osteogenesis through GSK-3β phosphorylation at Ser9 and consequent β-catenin activation, inhibiting osteoporosis

Fisetin is a bioactive flavonol that inhibits osteoclastogenesis and promotes osteoblastogenesis. However, the osteogenic activity of fisetin needs to be comprehensively elucidated. In the present study, we observed that fisetin significantly increased alkaline phosphatase (ALP) activity and bone mineralization in MC3T3-E1 preosteoblasts, accompanied by a significant increase in runt-related transcription factor 2 (RUNX2), ALP, collagen type Ⅰ alpha 1 (Col1α1), osterix (OSX), osteocalcin (OCN), and bone morphogenetic protein 4 (BMP4) expression. Furthermore, fisetin promoted vertebral formation in zebrafish larvae, with the highest fisetin concentration comparable with that observed in β-glycerophosphate treatment. Fisetin also inhibited prednisolone (PDS)-induced anti-osteoblastic genes, including nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), tartrate-resistant acid phosphatase-6 (ACP6), dendritic cell-specific transmembrane protein (DC-STAMP), and cathepsin K (CTSK). Fisetin potently mitigated the PDS-induced inhibition of ALP activity and bone mineralization, as well as vertebral resorption in zebrafish larvae. Moreover, we confirmed that fisetin-induced osteogenic effect was activated through phosphorylation of glycogen synthase kinase-3β (GSK-3β) at Ser9, consequently releasing β-catenin from the destructive complex to promote its nuclear translocation. β-Catenin inhibition by FH535 and the stabilization of GSK-3β by DOI hydrochloride remarkably inhibited fisetin-induced osteogenic activities, indicating that the GSK-3β/β-catenin signaling pathway plays a vital role in fisetin-induced osteogenesis. Collectively, our findings suggest that fisetin stimulates osteogenic activity and could be used as an effective strategy to prevent bone resorption.

Flavonoids and cellular stress: a complex interplay affecting human health

Flavonoid consumption has beneficial effects on human health, however, clinical evidence remains often inconclusive due to high interindividual variability. Although this high interindividual variability has been consistently observed in flavonoid research, the potential underlying reasons are still poorly studied. Especially the knowledge on the impact of health status on flavonoid responsiveness is limited and merits more investigation. Here, we aim to highlight the bidirectional interplay between flavonoids and cellular stress. First, the state-of-the-art concerning inflammatory stress and mitochondrial dysfunction is reviewed and a comprehensive overview of recent in vitro studies investigating the impact of flavonoids on cellular stress, induced by tumor necrosis factor α, lipopolysaccharide and mitochondrial stressors, is given. Second, we critically discuss the influence of cellular stress on flavonoid uptake, accumulation, metabolism and cell responses, which has, to our knowledge, never been extensively reviewed before. Next, we advocate the innovative insight that stratification of the general population based on health status can reveal subpopulations that benefit more from flavonoid consumption. Finally, suggestions are given for the development of future cell models that simulate the physiological micro-environment, including interindividual variability, since more mechanistic research is needed to establish scientific-based personalized food recommendations for specific subpopulations.

Medicinal plant compounds as promising inhibitors of coronavirus (COVID-19) main protease: an in silico study

The novel Coronavirus (COVID-19) has spread rapidly across the globe and has involved more than 215 countries and territories. Due to a lack of effective therapy or vaccine, urgent and concerted efforts are needed to identify therapeutic targets and medications. COVID-19 main protease represents a major target for drug treatment to inhibit viral function. The present study sought to evaluate medicinal plant compounds as potential inhibitors of the COVID-19 main protease using molecular docking and molecular dynamic analysis. The PDB files of COVID-19 main protease and some medicinal plant compounds were retrieved from the Protein Data Bank (http://www.rcsb.org) and Pubchem server, respectively. The Gromacs software was used for simulation studies, and molecular docking analysis was done using Autodock 4.2. The COVID-19 main protease simulation, compared with some phytochemicals docked to the COVID-19 main protease, were analyzed. Glabridin, catechin, and fisetin had the greatest tendency to interact with the COVID-19 main protease by hydrogen and hydrophobic interactions. Docking of these phytochemicals to COVID-19 main protease led to an increase in the radius of gyration (Rg), decrease in the Root mean square fluctuation (RMSF), and induced variation in COVID-19 main protease secondary structure. The high tendency interaction of glabridin, catechin, and fisetin to COVID-19 main protease induced conformational changes on this enzyme. These interactions can lead to enzyme inhibition. This simulated study indicates that these phytochemicals may be considered as potent inhibitors of the viral protease; however, more investigations are required to explore their potential medicinal use.Communicated by Ramaswamy H. Sarma.

Fisetin inhibits inflammation and induces autophagy by mediating PI3K/AKT/mTOR signaling in LPS-induced RAW264.7 cells

Background

Fisetin, a natural potent flavonoid, has various beneficial, pharmacological activities. In this study, we investigated expression changes of the fisetin regulating genes in lipopolysaccharide (LPS)-treated RAW264.7 cells and explored the role of fisetin in inflammation and autophagy.

Methods and results

Microarray analysis identified 1,071 genes that were regulated by fisetin in LPS-treated RAW264.7 cells, and these genes were mainly related to the process of immune system response. Quantitative real-time polymerase chain reaction and Bio-Plex analysis indicated that fisetin decreased the expression and secretion of several inflammatory cytokines in cells administered with LPS. Western blot analysis and immunofluorescence assay showed that fisetin decreased microtubule-associated protein 1 light-chain 3B (LC3B) and lysosome-associated membrane protein 1 (LAMP1) expression in LPS-treated cells, while the autophagy inhibitor chloroquine (CQ) could partially reverse this effect. In addition, fisetin reduced the elevated expression of p-PI3K, p-AKT and p-mTOR induced by LPS in a concentration-dependent manner.

Conclusions

Fisetin diminished the expression and secretion of inflammatory cytokines and facilitated autophagosome-lysosome fusion and degradation in LPS-treated RAW264.7 cells via inhibition of the PI3K/AKT/mTOR signaling pathway. Overall, the results of this study provide new clues for the anti-inflammatory mechanism of fisetin and explain the crosstalk between autophagy and inflammation to some extent.

Neuroprotective potential of fisetin in an experimental model of spinal cord injury: via modulation of NF-κB/IκBα pathway

AIM

To evaluate neuroprotective efficacy of fisetin against the experimental model of spinal cord injury (SCI).

MATERIALS AND METHODS

SCI was induced in male Sprague-Dawley rats by placing an aneurysm clip extradurally. Rats were treated either with vehicle or fisetin for 28 days after SCI.

RESULTS

Treatment with fisetin significantly attenuated SCI-induced alternations in mechano-tactile and thermal allodynia, hyperalgesia and nerve conduction velocities. SCI-induced upregulated tumor necrosis factor-alpha, interleukins, inducible nitric oxide synthase, cyclooxygenase-II, Bcl-2-associated X protein and caspase-3 mRNA expressions in the spinal cord and these were markedly reduced by fisetin. Spinal nuclear factor kappa B and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor-alpha protein levels were also significantly downregulated by fisetin. Hematoxylin and eosin staining of spinal cord suggested that fisetin significantly ameliorated histological aberrations such as neuronal degeneration, necrosis and inflammatory infiltration induced in it.

CONCLUSION

Fisetin exerts neuroprotection via modulation of nuclear factor kappa B/nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor-alpha pathway by inhibiting release of inflammatory mediators (inducible nitric oxide synthase and cyclooxygenase-II), proinflammatory cytokines (tumor necrosis factor-alpha and interleukins), apoptotic mediators (Bcl-2-associated X protein and caspase-3).

Fisetin protects against streptozotocin-induced diabetic cardiomyopathy in rats by suppressing fatty acid oxidation and inhibiting protein kinase R

This study examined if the Fisetin against streptozotocin-induced diabetic cardiomyopathy (DC) in rats involves regulating cardiac metabolism and suppressing protein kinase R (PKR). Male rats were divided (12/groups) as control (non-diabetic), control + Fisetin, T1DM, and T1DM + Fisetin. Fisetin was administered orally at a final dose of 2.5 mg/kg for 12 weeks. In T1DM1-induced rats, Fisetin prevented heart and final body weights loss, lowered circulatory levels troponin I and creatinine kinase-MB (CK-MB), increased fasting insulin levels, and improved ventricular systolic and diastolic functions. It also preserved the structure of the cardiomyocytes and reduced oxidative stress, fibrosis, protein levels of transforming growth factor-β1 (TGF-β1), collagenase 1A, caspase-3, and the activation of JNK, p53, and p38 MAPK. In the control and diabetic rats, Fisetin attenuated fasting hyperglycaemia, the increases in glucose levels after the oral and insulin tolerance tests, and HOMA-IR. It also increased cardiac glucose oxidation by increasing the activity of private dehydrogenase (PDH), phosphofructokinase (PFK), protein levels of PPAR-α and suppressed cardiac inflammation by inhibiting NF-κB. These effects were associated with a reduction in the activity of PKR and subsequent increase in the activity of eeukaryotic initiation factor 2 (eIF2) with a parallel increase in protein levels of p67, a cellular inhibitor of PKR. In cultured cardiomyocytes, Fisetin, prevented high glucose (HG)-induced activation of PKR and reduction in p67, in a dose-dependent manner. However, the effect of Fisetin on PKR was diminished in LG and HG-treated cardiomyocytes with p67-siRNA. In conclusion, Fisetin protects against DC in rats by improving cardiac glucose metabolism and suppressing PKR.

Immune checkpoint protein VSIG4 as a biomarker of aging in murine adipose tissue

Adipose tissue is recognized as a major source of systemic inflammation with age, driving age-related tissue dysfunction and pathogenesis. Macrophages (Mφ) are central to these changes yet adipose tissue Mφ (ATMs) from aged mice remain poorly characterized. To identify biomarkers underlying changes in aged adipose tissue, we performed an unbiased RNA-seq analysis of ATMs from young (8-week-old) and healthy aged (80-week-old) mice. One of the genes identified, V-set immunoglobulin-domain-containing 4 (VSIG4/CRIg), encodes a Mφ-associated complement receptor and B7 family-related immune checkpoint protein. Here, we demonstrate that Vsig4 expression is highly upregulated with age in perigonadal white adipose tissue (gWAT) in two mouse strains (inbred C57BL/6J and outbred NIH Swiss) independent of gender. The accumulation of VSIG4 was mainly attributed to a fourfold increase in the proportion of VSIG4+ ATMs (13%-52%). In a longitudinal study, VSIG4 expression in gWAT showed a strong correlation with age within a cohort of male and female mice and correlated strongly with physiological frailty index (PFI, a multi-parameter assessment of health) in male mice. Our results indicate that VSIG4 is a novel biomarker of aged murine ATMs. VSIG4 expression was also found to be elevated in other aging tissues (e.g., thymus) and was strongly induced in tumor-adjacent stroma in cases of spontaneous and xenograft lung cancer models. VSIG4 expression was recently associated with cancer and several inflammatory diseases with diagnostic and prognostic potential in both mice and humans. Further investigation is required to determine whether VSIG4-positive Mφ contribute to immunosenescence and/or systemic age-related deficits.

Trichosanthes tricuspidata Lour. Methanol Extract Exhibits Anti-Inflammatory Activity by Targeting Syk, Src, and IRAK1 Kinase Activity

Trichosanthes tricuspidata Lour., also known as T. palmata Roxb, T. bracteata Lam., T. puber Blume, and Modecca bracteata, is a vine belonging to the Cucurbitaceae family (English name: redball snake gourd). Distributed in China, South and East Asia, and tropical Australia, it has been traditionally used as a medicinal plant for its antifever, laxative, anthelmintic properties and for migraine treatment. In this paper, we examined the effects of Trichosanthes tricuspidata Lour. ethanol extract (Tt-ME) in vitro and in vivo. To confirm the effects of Tt-ME on inflammatory responses, we conducted experimental analyses including level of nitric oxide (NO) production, RT-PCR, and immunoblotting and using a HCl/EtOH-induced gastritis animal model. Tt-ME attenuated the release of NO and decreased mRNA levels of inducible NO synthase (iNOS), TNF-α, and IL-6 in lipopolysaccharide- (LPS-) induced macrophages in a concentration-dependent manner. Tt-ME time-dependently suppressed nuclear translocation of nuclear factor kappa B (NF-κB) subunits p50 and p65, activator protein (AP-1) subunits c-Fos and c-Jun, and STAT3 transcriptional activity by inhibiting nuclear translocation of p50, p65, c-Fos, c-Jun, and STAT3. Tt-ME significantly downregulated NF-κB, MAPK, and JAK2 signaling by targeting Syk, Src, and IRAK1 protein kinases. Furthermore, matrix metalloproteinase-9 (MMP-9) expression and cell migration were observed to be downregulated by Tt-ME in LPS-activated macrophages. In vivo studies on Tt-ME also produced similar trends in Hcl/EtOH-induced gastritis mouse models by inhibiting proinflammatory cytokines and the inflammatory signaling pathway. Our results strongly suggest that Tt-ME exerted anti-inflammatory activity in LPS-stimulated macrophages and mouse models of acute inflammatory disease.

Flavonoid fisetin alleviates kidney inflammation and apoptosis via inhibiting Src-mediated NF-κB p65 and MAPK signaling pathways in septic AKI mice

BACKGROUND

Sepsis is defined as end-organ dysfunction resulting from the host's inflammatory response to infection. One of the most common sepsis-injured organs is the kidneys, resulting in acute kidney injury (AKI) that contributes to the high morbidity and mortality, especially patients in the intensive care unit. Fisetin, a naturally occurring flavonoid, has been reported to protect against the rat of lipopolysaccharide (LPS)-induced acute lung injury. However, the effect of fisetin on septic AKI remains unknown.

PURPOSE

The current study proposed to systematically investigate the renoprotective effects and the underlying mechanisms of fisetin in septic AKI mice.

METHODS

The model of septic AKI was established on male C57BL/6 J mice by a single intraperitoneal injection of LPS (10 mg/kg). Fisetin was administrated by gavage at 100 mg/kg for 3 consecutive days before LPS injection and the mice were sacrificed at 16 h after LPS injection. The serum and kidney samples were evaluated for biochemical analysis, histopathological examinations as well as inflammation and apoptosis related gene/protein expression.

RESULTS

Pretreatment with fisetin significantly alleviated the elevated levels of serum creatinine and blood urea nitrogen in LPS-treated mice. Consistently, LPS induced renal damage as implied by histopathological score and the increased injury markers NGAL and KIM-1, which was attenuated by fisetin. Meanwhile, LPS injection triggered proinflammatory cytokine production and inflammation related proteins in the kidneys. However, fisetin inhibited renal expression of IL-6, IL-1β, TNF-α, HMGB1, iNOS and COX-2 to improve inflammatory response. Furthermore, fisetin effectively reduced the number of TUNEL positive apoptotic cells and suppressed apoptotic protein of Bcl-2, BAX and cleaved caspase-3 in the kidneys of LPS-induced septic AKI. Mechanistically, LPS stimulated the expression of TLR4 and the phosphorylation of NF-κB p65, MAPK (p38, ERK1/2 and JNK), Src and AKT in the injured kidneys, while fisetin notably suppressed the corresponding protein expression.

CONCLUSION

Fisetin alleviated kidney inflammation and apoptosis to protect against LPS-induced septic AKI mice via inhibiting Src-mediated NF-κB p65 and MAPK signaling pathways.

Antimicrobial activity and active compounds of a Rhus verniciflua Stokes extract

The Rhus verniciflua Stokes (RVS) extract is used as a traditional herbal medicine in Southeast Asian countries such as Korea and China. In the present study, one phenolic acid and six flavonoids were isolated from an 80% ethanol RVS extract to examine their antimicrobial activities. These compounds were identified as 3',4',7-trihydroxyflavone (1), methyl gallate (2), gallic acid (3), fusti (4), fisetin (5), butin (6), and sulfuretin (7) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and nuclear magnetic resonance spectroscopy. The antimicrobial activities of compounds 5 and 6 (at a dose of 16 μg/mL each) were superior to that of the control, cycloheximide (at a dose of 25 μg/mL), against Hypocrea nigricans; additionally, the activities of compounds 1 and 2 (at a dose of 8 μg/mL each) were superior to the control against Penicillium oxalicum. Also, chemical compounds 1 and 5 (at a dose of 16 μg/mL each) had higher activities than the control (25 μg/mL) against Trichoderma virens. Chemical compound 1 (at a dose of 8 μg/mL) had a similar activity to that of the control against Bacillus subtilis. The obtained results suggest that the RVS extract could be a promising food and nutraceutical source because of the antimicrobial properties of its phenolic compounds.

Antiviral and immunomodulatory effects of polyphenols on macrophages infected with dengue virus serotypes 2 and 3 enhanced or not with antibodies

Background: There is a lack of specific antiviral therapy against dengue virus (DENV) in current use. Therefore, a great proportion of dengue cases progress to severe clinical forms due to a complex interplay between virus and host immune response. It has been hypothesized that heterotypic non-neutralizing antibodies enhance DENV infection in phagocytic cells, and this induces an inflammatory response that is involved in the pathogenesis of severe dengue.

Purpose: To identify the antiviral and immunomodulatory effects of polyphenols on dengue virus infection.

Methods: Human U937-DC-SIGN macrophages were infected with DENV serotypes 2 or 3 in the presence or not of enhancing antibody 4G2. Viral titers and the secretion of tumor necrosis factor-alpha, IL-6, IL-10 and interferon-alpha were analyzed timely.

Results: DENV infection alone induced high production of IL-6 and TNF-α, but in the presence of 4G2 antibody, viral titers and TNF-α secretion were potentiated. Based on anti-inflammatory antecedents, the polyphenols curcumin, fisetin, resveratrol, apigenin, quercetin and rutin were tested for antiviral and immunomodulatory properties. Only quercetin and fisetin inhibited DENV-2 and DENV-3 infection in the absence or presence of enhancing antibody (>90%, p<0.001); they also inhibited TNF-α and IL-6 secretion (p<0.001).

Conclusion: Quercetin and fisetin down-regulate the production of proinflammatory cytokines induced by DENV infection enhanced by antibodies a mechanism involved in severe dengue.

HSP70/HSF1 axis, regulated via a PI3K/AKT pathway, is a druggable target in chronic lymphocytic leukemia

Considering the role played by the heat shock protein of 70 kDa (HSP70) in cancer, we characterized this protein and its major regulator, the heat shock factor 1 (HSF1), in chronic lymphocytic leukemia (CLL). We found both HSP70 and HSF1 overexpressed in CLL patients, correlated to poor prognosis and abnormally localized in the nucleus of leukemic B cells. The two proteins were strictly correlated each other and their levels decreased consensually in those patients responding to in vivo therapeutic regimens. HSP70 and HSF1 inhibition was proved to be effective in inducing a dose-dependent in vitro apoptosis of CLL B cells. Considering that HSF1 is finely regulated by kinases belonging to pathways triggered by rat sarcoma (RAS), we benefited from a previous proteomic study performed in CLL patients aiming to assess the activation/expression of key signaling proteins. We found that patients showing high levels of HSP70 also expressed high Akt-Ser473, thus activating HSF1. Inhibition of PI3K, which activates AKT, reduced the expression of HSF1 and HSP70. By contrast, HSP70-low patients displayed high activation of MEK1/2 and ERK1/2, known to negatively regulate HSF1. These data demonstrate that the HSP70 expression is regulated by the modulation of HSF1 activity through the activation of RAS-regulated pathways and suggest the HSP70/HSF1 interplay as an interesting target for antileukemic therapies. Finally, inhibition of PI3K, that activates AKT, reduced the expression of HSF1 and HSP70.

Suppression of Src and Syk in the NF-κB signaling pathway by Olea europaea methanol extract is leading to its anti-inflammatory effects

ETHNOPHARMACOLOGICAL RELEVANCE

Olea europaea L., (Oleaceae) has been used widely in folk medicine in the European Mediterranean islands, India, Asia, and other parts of the world. Although this plant has high ethnopharmacological value for treating inflammatory diseases, the molecular mechanisms of how it inhibits the inflammatory response are not fully understood. In this study, we sought to identify the anti-inflammatory mechanisms of this plant.

MATERIALS AND METHODS

Using macrophages, we investigated the effects of O. europaea L. methanol extract (Oe-ME) and ethanol extract (Oe-EE) on the production of inflammatory mediator nitric oxide (NO) and prostaglandin E₂ (PGE₂), the expression levels of pro-inflammatory genes and intracellular inflammatory signaling activities.

RESULTS

Oe-ME and Oe-EE suppressed the production of NO in lipopolysaccharide-(LPS-), Pam3CSK4-, and poly (I:C)-stimulated RAW264.7 cells; importantly, no cytotoxicity was observed. Oe-ME and Oe-EE reduced production of PGE₂ without exhibiting cytotoxicity. The mRNA expression levels of cyclooxygenase-2 (COX-2), inducible NO synthase (iNOS), IL-6, IL-1β, and tumor necrosis factor (TNF)-α were down-regulated by Oe-ME and Oe-EE. Nuclear fraction and whole lysate immunoblotting analyses and overexpression experiments strongly suggested that Oe-ME decreased the translocation of p65 and p50 (nuclear factors of the NF-κB subunit) as well as Src and Syk.

CONCLUSION

These results suggest that Oe-ME exerts its anti-inflammatory effects by targeting Src and Syk in the NF-κB signaling pathway.

Fisetin and Quercetin: Promising Flavonoids with Chemopreventive Potential

Despite advancements in healthcare facilities for diagnosis and treatment, cancer remains the leading cause of death worldwide. As prevention is always better than cure, efficient strategies are needed in order to deal with the menace of cancer. The use of phytochemicals as adjuvant chemotherapeutic agents in heterogeneous human carcinomas like breast, colon, lung, ovary, and prostate cancers has shown an upward trend during the last decade or so. Flavonoids are well-known products of plant derivatives that are reportedly documented to be therapeutically active phytochemicals against many diseases encompassing malignancies, inflammatory disorders (cardiovascular disease, neurodegenerative disorder), and oxidative stress. The current review focuses on two key flavonols, fisetin and quercetin, known for their potential pharmacological relevance. Also, efforts have been made to bring together most of the concrete studies pertaining to the bioactive potential of fisetin and quercetin, especially in the modulation of a range of cancer signaling pathways. Further emphasis has also been made to highlight the molecular action of quercetin and fisetin so that one could explore cancer initiation pathways and progression, which could be helpful in designing effective treatment strategies.

Dehydroabietic Acid Suppresses Inflammatory Response Via Suppression of Src-, Syk-, and TAK1-Mediated Pathways

Dehydroabietic acid (DAA) is a naturally occurring diterpene resin acid derived from coniferous plants such as Pinus and Picea. Various bioactive effects of DAA have been studied including antibacterial, antifungal, and anticancer activities. However, the anti-inflammatory mechanism of DAA remains unclear. We evaluated the anti-inflammatory effect of DAA in macrophage cell lines. Dehydroabietic acid clearly reduced nitric oxide (NO) production and inflammatory gene expression decreased according to RT-PCR results. Dehydroabietic acid displayed anti-inflammatory activity at the transcriptional level in results from NF-κB- or AP-1-mediated luciferase assays. To identify the DAA target protein, we investigated NF-κB and AP-1 pathways by Western blotting analysis. Dehydroabietic acid suppressed the activity of proto-oncogene tyrosine protein kinase (Src) and spleen tyrosine kinase (Syk) in the NF-κB cascade and transforming growth factor beta-activated kinase 1 (TAK1) in the AP-1 cascade. Using overexpression strategies, we confirmed that DAA targeted these kinases. Our findings demonstrate the anti-inflammatory effects and molecular mechanism of DAA. This suggests that DAA has potential as a drug or supplement to ameliorate inflammation.

Mycetia cauliflora methanol extract exerts anti-inflammatory activity by directly targeting PDK1 in the NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Mycetia cauliflora Reinw. (Rubiaceae) has been used as a traditional remedy to ameliorate clinical signs of inflammatory diseases, including pain, inflammation, ulcers, and wounds. Among the Mycetia subfamilies, the molecular and cellular mechanisms of Mycetia longifolia (Rubiaceae) have been studied. However, those of Mycetia cauliflora are not clearly understood. Comprehensive investigation of this plant is necessary to evaluate its potential for ethnopharmacological use.

MATERIALS

and methods: The activities of Mycetia cauliflora methanol extract (Mc-ME) on the secretion of inflammatory mediators, the mRNA expression of proinflammatory cytokines, and identification of its molecular targets were elucidated using lipopolysaccharide (LPS)-induced macrophage-like cells. Moreover, the suppressive actions of Mc-ME were examined in an LPS-induced peritonitis mouse model.

RESULTS

At nontoxic concentrations, Mc-ME downregulated the release of nitric oxide (NO), the mRNA expression of inducible nitric oxide synthase (iNOS), and the mRNA expression of interleukin (IL)-1β from LPS-activated RAW264.7 cells. This extract also inhibited the nuclear translocation of p65 and p50 and the phosphorylation of IκBα, IKK, and AKT. Western blot analysis and in vitro kinase assays confirmed that phosphoinositide-dependent kinase-1 (PDK1) is the direct immunopharmacological target of Mc-ME effect. In addition, Mc-ME significantly reduced inflammatory signs in an animal model of acute peritonitis. These effects were associated with decreased NO production and decreased AKT phosphorylation.

CONCLUSION

Our results suggest that Mc-ME displays anti-inflammatory actions in LPS-treated macrophage-like cells and in an animal model of acute inflammatory disease. These actions are preferentially managed by targeting PDK1 in the nuclear factor (NF)-κB signaling pathway.

Fisetin, a plant flavonoid ameliorates doxorubicin-induced cardiotoxicity in experimental rats: the decisive role of caspase-3, COX-II, cTn-I, iNOs and TNF-α

Doxorubicin (DOX) is a widely used anthracycline antibiotic for the management of carcinoma. However, it is associated with cardiotoxicity. Fisetin is a plant flavonoid reported to have anti-inflammatory and antiapoptotic potential. To evaluate the cardioprotective potential of fisetin in DOX-induced cardiotoxicity in experimental rats. Sprague-Dawley rats were pre-treated with either fisetin (10, 20 and 40 mg/kg) or sitagliptin (10 mg/kg, p.o.) for 7 days. Cardiac toxicity was induced in rats (except the normal group) by doxorubicin (15 mg/kg i.p.) on 8th day. Various behavioral, biochemical, molecular and histological parameters were assessed in cardiac tissue. DOX-induced alterations in electrocardiographic, hemodynamic and left ventricular function were significantly (p < 0.05) inhibited by fisetin (20 and 40 mg/kg) treatment. Fisetin significantly decrease (p < 0.05) DOX-induced elevated serum CK-MB, LDH, AST, ALT and ALP levels. DOX-induced elevated cardiac oxido-nitrosative (SOD, GSH, MDA and NO) was significantly inhibited (p < 0.05) by fisetin. Up-regulated cardiac caspase-3, COX-II, cTn-I, iNOs, TNF-α, and IL-1β mRNA, as well as protein expressions were significantly decreased (p < 0.05) by fisetin treatment. It also significantly (p < 0.05) attenuated DOX-induced histopathological alterations in cardiac tissue. In conclusion, the fisetin exerts its cardioprotective potential against DOX-induced toxicity via inhibition of multiple pathways including oxidative stress (SOD, GSH, MDA and NO), inflammation (COX-II, TNF-α, and IL-1β), and apoptosis (Caspase-3). Therefore, fisetin can be considered as a potential cardioprotective agent during the management of carcinoma using doxorubicin anthracyclines.

Alisma canaliculatum ethanol extract suppresses inflammatory responses in LPS-stimulated macrophages, HCl/EtOH-induced gastritis, and DSS-triggered colitis by targeting Src/Syk and TAK1 activities

ETHNOPHARMACOLOGICAL RELEVANCE

Alisma canaliculatum A.Braun & C.D.Bouché, distributed in Korea, Japan, China, and Taiwan, is a traditional medicine. In particular, the stem and root of Alisma canaliculatum A.Braun & C.D.Bouché are prescribed to relieve various inflammatory symptoms resulting from nephritis, cystitis, urethritis, and dropsy.

AIM OF STUDY

However, the curative mechanism of Alisma canaliculatum A.Braun & C.D.Bouché with respect to inflammatory symptoms is poorly understood. In this study, the curative roles of this plant in various inflammatory conditions as well as its inhibitory mechanism were aimed to examine using an ethanol extract (Ac-EE).

MATERIALS AND METHODS

Anti-inflammatory effects of Ac-EE were evaluated in lipopolysaccharide (LPS)-induced macrophages in vitro and HCl/EtOH-stimulated mouse model of gastritis and DSS-treated mouse model of colitis. To determine the potentially active anti-inflammatory components in this extracts, we employed HPLC. We also used kinase assays, reporter gene assay, immunoprecipitation analysis and target enzyme overexpressing cell analysis to analyze the molecular mechanisms and the target molecules.

RESULTS

This extract dose-dependently inhibited the production of nitric oxide (NO) and prostaglandin E₂ (PGE₂) from RAW264.7 cells and peritoneal macrophages activated by lipopolysaccharide (LPS). Additionally, Ac-EE ameliorated inflammatory symptoms resulting from gastritis and colitis. Ac-EE down-regulated the mRNA levels of inducible NO synthase (iNOS), tumor necrosis factor (TNF)-α, and cyclooxygenase-2 (COX-2). Ac-EE also blocked the nuclear translocation of nuclear factor (NF)-κB and activator protein (AP)- 1 in LPS-stimulated RAW264.7 cells. By analyzing the target signaling molecules activating these transcription factors, we found that Src and Syk, as well as molecular association between TAK1 and mitogen-activated protein kinase kinase 4/7 (MKK4/7), were targeted by Ac-EE.

CONCLUSIONS

Our data suggest that the Ac-EE NF-κB/AP-1-targeted anti-inflammatory potential is mediated by suppression of Src and Syk as well as the complex formation between TAK1 and its substrate proteins MKK4/7.

Src Is a Prime Target Inhibited by Celtis choseniana Methanol Extract in Its Anti-Inflammatory Action

Celtis choseniana is the traditional plant used at Korea as a herbal medicine to ameliorate inflammatory responses. Although Celtis choseniana has been traditionally used as a herbal medicine at Korea, no systemic research has been conducted on its anti-inflammatory activity. Therefore, the present study explored an anti-inflammatory effect and its underlying molecular mechanism using Celtis choseniana methanol extract (Cc-ME) in macrophage-mediated inflammatory responses. In vitro anti-inflammatory activity of Cc-ME was evaluated using RAW264.7 cells and peritoneal macrophages stimulated by lipopolysaccharide (LPS), pam3CSK4 (Pam3), or poly(I:C). In vivo anti-inflammatory activity of Cc-ME was investigated using acute inflammatory disease mouse models, such as LPS-induced peritonitis and HCl/EtOH-induced gastritis. The molecular mechanism of Cc-ME-mediated anti-inflammatory activity was examined by Western blot analysis and immunoprecipitation using whole cell and nuclear fraction prepared from the LPS-stimulated RAW264.7 cells and HEK293 cells. Cc-ME inhibited NO production and mRNA expression of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX-2), and tumor necrosis factor-alpha (TNF-α) in the RAW264.7 cells and peritoneal macrophages induced by LPS, pam3, or poly(I:C) without cytotoxicity. High-performance liquid chromatography (HPLC) analysis showed that Cc-ME contained anti-inflammatory flavonoids quercetin, luteolin, and kaempferol. Among those, the content of luteolin, which showed an inhibitory effect on NO production, was highest. Cc-ME suppressed the NF-κB signaling pathway by targeting Src and interrupting molecular interactions between Src and p85, its downstream kinase. Moreover, Cc-ME ameliorated the morphological finding of peritonitis and gastritis in the mouse disease models. Therefore, these results suggest that Cc-ME exerted in vitro and in vivo anti-inflammatory activity in LPS-stimulated macrophages and mouse models of acute inflammatory diseases. This anti-inflammatory activity of Cc-ME was dominantly mediated by targeting Src in NF-κB signaling pathway during macrophage-mediated inflammatory responses.

Momordica charantia Inhibits Inflammatory Responses in Murine Macrophages via Suppression of TAK1

Momordica charantia known as bitter melon is a representative medicinal plant reported to exhibit numerous pharmacological activities such as antibacterial, antidiabetic, anti-inflammatory, anti-oxidant, antitumor, and hypoglycemic actions. Although this plant has high ethnopharmacological value for treating inflammatory diseases, the molecular mechanisms by which it inhibits the inflammatory response are not fully understood. In this study, we aim to identify the anti-inflammatory mechanism of this plant. To this end, we studied the effects of its methanol extract (Mc-ME) on lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Specifically, we evaluated nitric oxide (NO) production, mRNA expression of inflammatory genes, luciferase reporter gene activity, and putative molecular targets. Mc-ME blocked NO production in a dose-dependent manner in RAW264.7 cells; importantly, no cytotoxicity was observed. Moreover, the mRNA expression levels of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 were decreased by Mc-ME treatment in a dose-dependent manner. Luciferase assays and nuclear lysate immunoblotting analyses strongly indicated that Mc-ME decreases the levels of p65 [a nuclear factor (NF)-[Formula: see text]B subunit] and c-Fos [an activator protein (AP)-1 subunit]. Whole lysate immunoblotting assays, luciferase assays, and overexpression experiments suggested that transforming growth factor [Formula: see text]-activated kinase 1 (TAK1) is targeted by Mc-ME, thereby suppressing NF-[Formula: see text]B and AP-1 activity via downregulation of extracellular signal-regulated kinases (ERKs) and AKT. These results strongly suggest that Mc-ME exerts its anti-inflammatory activity by reducing the action of TAK1, which also affects the activation of NF-[Formula: see text]B and AP-1.

Src is the primary target of aripiprazole, an atypical antipsychotic drug, in its anti-tumor action

Aripiprazole (ARP) is an atypical anti-psychotic drug widely used to treat schizophrenia and bipolar disorder. The pharmacological effects of ARP on cancer cells are still poorly understood. In this study, anti-cancer effects of ARP on various malignant tumor cells and its molecular mechanism were further carefully examined by using cell proliferation assay, xenograft mouse model, immunoblotting analysis, migration assay, luciferase reporter gene assay, kinase assay, and overexpression strategy. Treatment with ARP induced cytotoxicity in U251 glioma cells, MKN-1 gastric adenosquamous carcinoma cells, and CT26 colon carcinoma cells. ARP suppressed cell proliferation of LN428, MDA-MB-231, and HEK293 cells. Pro-apoptotic factors active caspase-3, -8, and -9, as well as p53, were upregulated, whereas the protein and mRNA levels of anti-apoptotic factor B-cell lymphoma 2 (Bcl-2) decreased. In agreement with the in vitro results, ARP compound also significantly suppressed the growth of tumor masses formed by injecting CT26 colon cancer cells into mice. ARP treatment also effectively decreased the migratory ability of U251 glioma cells by downregulating metalloproteinase-9. Levels of phosphorylated Src, phosphorylated phosphatidylinositide 3-kinase (PI3K), and phosphorylated signal transducer and activator of transcription 3 (STAT3) were significantly decreased following ARP treatment. ARP compound reduced the kinase activity of Src. Our studies suggest that Src may be an important target molecule linked to the antitumor effects of ARP.

Fisetin: A bioactive phytochemical with potential for cancer prevention and pharmacotherapy

A wide variety of chronic diseases, such as neurodegenerative and cardiovascular disorders, diabetes mellitus, osteoarthtitis, obesity and various cancers, are now being treated with cost effective phytomedicines. Since synthetic medicines are very expensive, concerted efforts are being made in developing and poor countries to discover cost effective medicines for the treatment of non-communicable diseases (NCDs). Understanding the underlying mechanisms of bioactive medicines from natural sources would not only open incipient avenues for the scientific community and pharmaceutical industry to discover new drug molecules for the therapy of NCDs, but also help to garner knowledge for alternative therapeutic approaches for the management of chronic diseases. Fisetin is a polyphenolic molecule of flavonoids class, and belongs to the bioactive phytochemicals that have potential to block multiple signaling pathways associated with NCDs such as cell division, angiogenesis, metastasis, oxidative stress, and inflammation. The emerging evidence suggests that fisetin may be useful for the prevention and management of several types of human malignancies. Efforts are being made to enhance the bioavailability of fisetin after oral administration to prevent and/or treat cancer of the liver, breast, ovary and other organs. The intent of this review is to highlight the in vitro and in vivo activities of fisetin and to provide up-to-date information about the molecular interactions of fisetin with its cellular targets involved in cancer initiation, promotion and progression as well as to focus on strategies underway to increase the bioavailability and reduce the risk of deleterious effects, if any, associated with fisetin administration.

Anti-Inflammatory Effect of Piper attenuatum Methanol Extract in LPS-Stimulated Inflammatory Responses

Piper attenuatum is used as a traditional medicinal plant in India. One of the substances in P. attenuatum has been suggested to have anti-inflammatory effects. However, there is insufficient research about the anti-inflammatory mechanisms of action of P. attenuatum. The effects of P. attenuatum methanol extract (Pa-ME) on the production of inflammatory mediators nitric oxide (NO) and prostaglandin E₂ (PGE₂), the expression of proinflammatory genes, the translocation level of transcription factors, and intracellular signaling activities were investigated using macrophages. Pa-ME suppressed the production of NO and PGE₂ in lipopolysaccharide- (LPS-), pam3CSK4-, and poly(I:C)-stimulated RAW264.7 cells without displaying cytotoxicity. The mRNA expression levels of inducible NO synthase (iNOS) and cyclooxygenase 2 (COX-2) were decreased by Pa-ME. P-ME reduced the translocation of p50/NF-κB and AP-1 (c-Jun and c-Fos), as well as the activity of their upstream enzymes Src, Syk, and TAK1. Immunoprecipitation analysis showed failure of binding between their substrates, phospho- (p-) p85 and p-MKK3/6. p-p85 and p-MKK3/6, which were induced by overexpression of Src, Syk, and TAK1, were also reduced by Pa-ME. Therefore, these results suggest that Pa-ME exerts its anti-inflammatory effects by targeting Src and Syk in the NF-κB signaling pathway and TAK1 in the AP-1 signaling pathway.

Src and Syk contribute to the anti-inflammatory activities of Achyranthes aspera ethanolic extract

ETHNOPHARMACOLOGICAL RELEVANCE

Nuclear factor-kappa B (NF-κB) plays pivotal roles in inflammation. Src and Syk are two tyrosine kinases that act upstream of NF-κB signaling. Although Achyranthes aspera L. (A. aspera) has been used as a traditional medicine to treat fevers and inflammatory ailments and heal wounds, the molecular mechanisms of its anti-inflammatory actions are not yet fully understood.

MATERIALS AND METHODS

In this study, we evaluated the anti-inflammatory effect of A. aspera ethanol extract (Aa-EE). To determine the mechanism by which Aa-EE dampens the inflammatory response, nitric oxide (NO) production and the mRNA expression levels of tumor necrosis factor (TNF)-α and inducible nitric oxide synthase (iNOS) were examined by Griess assay and RT-PCR. Luciferase assays and immunoblotting were also conducted to examine how Aa-EE regulates the NF-κB pathway.

RESULTS

Aa-EE reduced NO production up to 60% without any cytotoxicity. This extract was found to downregulate the mRNA expression levels of inflammatory genes. Aa-EE blocked NF-κB promoter activity induced by both TNF-α and adaptor molecule MyD88 (about 70% and 40%, respectively). Moreover, nuclear translocation of p65 and IκBα phosphorylation were also inhibited. Furthermore, Aa-EE inactivated two upstream signaling molecules, the Src and Syk kinases. In accordance with these data, the kinase activities of Src and Syk were decreased by 50% and 80%, respectively. The anti-inflammatory action of Aa-EE was also confirmed in a gastritis model.

CONCLUSION

Our data suggest that Aa-EE targets NF-κB to exert its anti-inflammatory properties by suppressing Src and Syk. Therefore, our study raises the possibility that this extract can be developed as a novel natural anti-inflammatory remedy.

Beauvericin, a cyclic peptide, inhibits inflammatory responses in macrophages by inhibiting the NF-κB pathway

Beauvericin (BEA), a cyclic hexadepsipeptide produced by the fungus Beauveria bassiana, is known to have anti-cancer, anti-inflammatory, and anti-microbial actions. However, how BEA suppresses macrophage-induced inflammatory responses has not been fully elucidated. In this study, we explored the anti-inflammatory properties of BEA and the underlying molecular mechanisms using lipopolysaccharide (LPS)-treated macrophage-like RAW264.7 cells. Levels of nitric oxide (NO), mRNA levels of transcription factors and the inflammatory genes inducible NO synthase (iNOS) and interleukin (IL)-1, and protein levels of activated intracellular signaling molecules were determined by Griess assay, semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), luciferase reporter gene assay, and immunoblotting analysis. BEA dose-dependently blocked the production of NO in LPS-treated RAW264.7 cells without inducing cell cytotoxicity. BEA also prevented LPS-triggered morphological changes. This compound significantly inhibited nuclear translocation of the NF-κB subunits p65 and p50. Luciferase reporter gene assays demonstrated that BEA suppresses MyD88-dependent NF-κB activation. By analyzing upstream signaling events for NF-κB activation and overexpressing Src and Syk, these two enzymes were revealed to be targets of BEA. Together, these results suggest that BEA suppresses NF-κB-dependent inflammatory responses by suppressing both Src and Syk.

Syk Plays a Critical Role in the Expression and Activation of IRAK1 in LPS-Treated Macrophages

To address how interleukin-1 receptor-associated kinase 1 (IRAK1) is controlled by other enzymes activated by toll-like receptor (TLR) 4, we investigated the possibility that spleen tyrosine kinase (Syk), a protein tyrosine kinase that is activated at an earlier stage during TLR4 activation, plays a central role in regulating the functional activation of IRAK1. Indeed, we found that overexpression of myeloid differentiation primary response gene 88 (MyD88), an adaptor molecule that drives TLR signaling, induced IRAK1 expression and that piceatannol, a Syk inhibitor, successfully suppressed the MyD88-dependent upregulation of IRAK1 under LPS treatment conditions. Interestingly, in Syk-knockout RAW264.7 cells, IRAK1 activity was almost completely blocked after LPS treatment, while providing a Syk-recovery gene to the knockout cells successfully restored IRAK1 expression. According to our measurements of IRAK1 mRNA levels, the transcriptional upregulation of IRAK1 was induced by LPS treatment between 4 and 60 min, and this can be suppressed in Syk knockout cells, providing an effect similar that that seen under piceatannol treatment. The overexpression of Syk reverses this effect and leads to a significantly higher IRAK1 mRNA level. Collectively, our results strongly suggest that Syk plays a critical role in regulating both the activity and transcriptional level of IRAK1.

JS-III-49, a hydroquinone derivative, exerts anti-inflammatory activity by targeting Akt and p38

Since previous studies have reported that hydroquinone (HQ) exerted immunosuppressive and anti-inflammatory activity, various HQ derivatives have been synthesized and their biological activities investigated. In this study, we explored the anti-inflammatory activity of JS-III-49, a novel HQ derivative, in macrophage-mediated inflammatory responses. JS-III-49 suppressed the production of the inflammatory mediators nitric oxide (NO) and prostaglandin E₂ (PGE₂) and down-regulated the mRNA expression of the inflammatory enzymes cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) as well as the expression of the pro-inflammatory cytokines interleukin-6 (IL-6) and IL-1b without cytotoxicity in LPS-stimulated RAW264.7 cells. JS-III-49 inhibited nuclear translocation of the NF-kB transcription factors p65 and p50 by directly targeting Akt, an upstream kinase of the NF-kB pathway, in LPS-stimulated RAW264.7 cells. However, JS-III-49 did not directly inhibit the kinase activities of Src and Syk, which are upstream kinases of Akt, in LPS-stimulated RAW264.7 cells. Moreover, JS-III-49 suppressed the nuclear translocation of c-Fos, one of the components of AP-1, by specifically targeting p38, an upstream mitogen-activated protein kinase (MAPK) in the AP-1 pathway in LPS-stimulated RAW264.7 cells. These results suggest that JS-III-49 plays an anti-inflammatory role in LPS-stimulated macrophages by targeting Akt and p38 in the NF-kB and AP-1 pathways, respectively.

AKT-targeted anti-inflammatory activity of the methanol extract of Chrysanthemum indicum var. albescens

ETHNOPHARMACOLOGICAL RELEVANCE

Wild chrysanthemum (Chrysanthemum indicum) is one of well-known medicinal plants traditionally used in Korea and China. As a variant of wild chrysanthemum, white wild chrysanthemum (Chrysanthemum indicum var. albescens) is also ethnopharmacologically applied to treat various symptoms such as inflammatory diseases.

AIM OF STUDY

Although the anti-inflammatory activity of Chrysanthemum indicum has been reported, the anti-inflammatory activity and underlying molecular mechanism of white wild chrysanthemum are poorly understood.

MATERIALS AND METHODS

The effects of Chrysanthemum indicum var. albescens methanol extract (Civ-ME) on the production of inflammatory mediators, expression of pro-inflammatory genes, cell viability, and the activities of intracellular signaling molecules and transcription factors were investigated in lipopolysaccharide (LPS)-stimulated RAW264.7 cells.

RESULTS

Civ-ME suppressed the production of both nitric oxide (NO) and prostaglandin E₂ (PGE₂) without cytotoxicity in LPS-stimulated RAW264.7 cells. Civ-ME was found to reduce the mRNA levels of inflammatory genes such as inducible NO synthase (iNOS) and tumor necrosis factor (TNF)-α and reduced NF-κB-mediated transcriptional activation. Civ-ME inhibited the nuclear translocation of NF-κB (p65 and p50), and its upstream signaling composed of IκBα and IKKα/β. An NF-κB luciferase reporter gene assay and an in vitro kinase assay confirmed that AKT1 and AKT2 might be direct pharmacological targets of Civ-ME. In addition, luteolin was identified by HPLC analysis as the main active pharmacological components of Civ-ME.

CONCLUSION

Civ-ME exerts an anti-inflammatory effect by targeting AKT1 and AKT2 in the NF-κB signaling pathway in macrophage-mediated inflammatory responses.

Src/Syk-Targeted Anti-Inflammatory Actions of Triterpenoidal Saponins from Gac (Momordica cochinchinensis) Seeds

Momordica cochinchinensis Spreng (family Cucurbitaceae), also known as gac, or red melon, is an edible Southeast Asian fruit valued for its nutritional and medicinal properties. Specifically, Momordicae Semen, the seeds of the gac fruit, is used in traditional Chinese medicine to treat boils, rheumatic pain, muscle spasm, hemorrhoids, and hemangiomas. In this study, a chemical investigation into a gac seed ethanol (EtOH) extract resulted in the identification of three triterpenoidal saponins (1-3), which were investigated for their anti-inflammatory effects. Among the saponins, momordica saponin I (compound 3) reduced the production of nitric oxide (NO) in LPS-activated RAW264.7 cells without inducing cytotoxicity. The mRNA levels of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 were decreased by momordica saponin I. Additionally, the translocation of p65 and p50 (subunits of the transcription factor NF-[Formula: see text]B) into the nucleus was remarkably inhibited. Furthermore, the phosphorylation levels of inflammatory signaling proteins (I[Formula: see text]B[Formula: see text], Src, and Syk) known to be upstream regulatory molecules of p65 were decreased under momordica saponin I-treated conditions. The molecular targets of momordica saponin I were confirmed in overexpression experiments and through immunoblot analyses with Src and Syk. This study provides evidence that momordica saponin I could be beneficial in treating inflammatory diseases, and should be considered a bioactive immunomodulatory agent with anti-inflammatory properties.

Thymoquinone: An IRAK1 inhibitor with in vivo and in vitro anti-inflammatory activities

Thymoquinone (TQ) is a bioactive component of black seed (Nigella sativa) volatile oil and has been shown to have anti-oxidative, anti-inflammatory, and anti-cancer properties. In the present study, we explored the molecular mechanisms that underlie the anti-inflammatory effect of TQ and its target proteins using lipopolysaccharide (LPS)-stimulated murine macrophage-like RAW264.7 and human monocyte-like U937 cells, together with LPS/D-galactosamine (GalN)-induced acute hepatitis and HCl/EtOH-induced gastritis mouse models. TQ strongly inhibited the production of nitric oxide (NO) and repressed NO synthase (iNOS), tumor necrosis factor (TNF)-α, cyclooxygenase (COX)−2, interleukin (IL)−6, and IL-1β expression in LPS-activated RAW264.7 cells. Treatment of LPS/D-GalN–induced hepatitis and EtOH/HCl–induced gastritis mouse models with TQ significantly ameliorated disease symptoms. Using luciferase reporter gene assays, we also showed that the nuclear levels of transcription factors and phosphorylation patterns of signaling proteins, activator protein (AP)−1, and nuclear factor (NF)-κB pathways were all affected by TQ treatment. Finally, we used additional kinase and luciferase validation assays with interleukin-1 receptor-associated kinase 1 (IRAK1) to show that IRAK1 is directly suppressed by TQ treatment. Together, these findings strongly suggest that the anti-inflammatory actions of TQ are caused by suppression of IRAK-linked AP-1/NF-κB pathways.

Syk-Mediated Suppression of Inflammatory Responses by Cordyceps bassiana

The fruit body of artificially cultivated Cordyceps bassiana has been reported to exhibit anti-inflammatory and anticancer activities. Although it has been suggested that the fruit body has neutraceutic and pharmaceutic biomaterial potential, the exact anti-inflammatory molecular mechanism has not been fully elucidated. In this study, we demonstrated the immunopharmacologic activity of Cordyceps bassiana under in vitro conditions and investigated its anti-inflammatory mechanism. Water extract (Cm-WE) of the fruit body of artificially cultivated Cordyceps bassiana without polysaccharide fractions reduced the expression of the proinflammatory genes cyclooxygenase (COX)-2, interleukin (IL)-12, and inducible nitric oxide synthase (iNOS) and promoted the expression of the anti-inflammatory gene IL-10 in lipopolysaccharide (LPS)-treated RAW264.7 cells. In addition, this fraction suppressed proliferation and interferon (IFN)-[Formula: see text] production in splenic T lymphocytes. Cm-WE blocked the activation of nuclear factor (NF)-[Formula: see text]B and activator protein (AP)-1 and their upstream inflammatory signaling cascades, including Syk, MEK, and JNK. Using kinase assays, Syk was identified as the target enzyme most strongly inhibited by Cm-WE. These results strongly suggest that Cm-WE suppresses inflammatory responses by inhibiting Syk kinase activity, with potential implications for novel neutraceutic and pharmaceutic biomaterials.

Cerbera manghas methanol extract exerts anti-inflammatory activity by targeting c-Jun N-terminal kinase in the AP-1 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Cerbera manghas L. (Apocynaceae) is a medicinal plant traditionally used to ameliorate the clinical signs of inflammatory diseases and hypertension.

AIM OF STUDY

Although C. manghas L. has long been used as a traditional remedy for various diseases, the underlying molecular and cellular mechanisms are poorly understood. A detailed investigation of these mechanisms is necessary to demonstrate the ethnopharmaceutical utility of this plant.

MATERIALS AND METHODS

The effects of C. manghas methanol extract (Cm-ME) on the production of inflammatory mediators and the expression of proinflammatory cytokines and identification of molecular targets were investigated using lipopolysaccharide (LPS)-treated macrophages in vitro. In addition, the inhibitory effects of Cm-ME orally administered were tested by LPS/D-galactosamine (D-GalN)-induced hepatitis and LPS-induced peritonitis mouse models in vivo.

RESULTS

Cm-ME downregulated the production of prostaglandin (PG)E₂ and the mRNA expression of cyclooxygenase (COX)-2, tumor necrosis factor (TNF)-α, and interleukin (IL)-1β in LPS-stimulated RAW264.7 cells under non-toxic concentration of Cm-ME. This extract inhibited the nuclear translocation of c-Jun and p-ATF2, the phosphorylation of JNK and p38, and AP-1 activity. Western blot analysis and in vitro kinase assay confirmed that JNK is a direct pharmacological target of Cm-ME action. In addition, Cm-ME significantly ameliorated the clinical signs of LPS/D-GalN-induced hepatitis and lowered the production of nitric oxide (NO) and the phosphorylation of JNK in LPS-induced peritonitis conditions.

CONCLUSION

Cm-ME exerts anti-inflammatory actions on LPS-stimulated macrophages and in mouse models of acute inflammatory disease. These actions are predominantly mediated by targeting JNK in the AP-1 signaling pathway.