Regulatory effect of daphnetin, a coumarin extracted from Daphne odora, on the balance of Treg and Th17 in collagen-induced arthritis

T helper cell 17/regulatory T cell balance regulates ulcerative colitis and the therapeutic role of natural plant components: a review

Ulcerative colitis (UC) is a chronic relapsing inflammatory disease characterized by progressive mucosal damage. The incidence rate of UC is rising rapidly, which makes the burden of medical resources aggravated. In UC, due to various pathogenic factors such as mucosal immune system disorders, gene mutations and environmental factors disrupting the mucosal barrier function, the midgut pathogenic bacteria and exogenous antigens translocate into the lamina propria, thereby aggravating the inflammatory response and further damages the mucosal barrier. During the progression of UC, Th17 populations that cause inflammation generally increase, while Tregs that suppress Th17 activity decrease. Among them, Th17 mediates immune response, Treg mediates immunosuppression, and the coordinated balance of the two plays a key role in the inflammation and immune process of UC. Natural plant components can regulate biological processes such as immune inflammation from multiple levels of proinflammatory cytokines and signaling pathways. These characteristics have unique advantages and broad prospects in the treatment of UC. In immunomodulation, there is substantial clinical and experimental evidence for the modulatory role of natural plant products in restoring balance between Th17/Treg disturbances in UC. This review summarizes the previous studies on the regulation of Th17/Treg balance in UC by natural plant active ingredients, extracts, and traditional Chinese medicine prescriptions, and provides new evidence for the development and design of lead compounds and natural new drugs for the regulation of Th17/Treg balance in the future, and then provides ideas and evidence for future clinical intervention in the treatment of UC immune disorders and clinical trials.

Kinases and their derived inhibitors from natural products

Protein kinase dysregulation is a hallmark of many cancers, yet their tumorigenic mechanisms remain elusive despite 60 years of study. Since learning that their mechanism includes catalyzing phosphorylation of amino acids in protein substrates, researchers began devising their inhibition strategies. Initially, protein kinase inhibitors (PKIs) derived from natural products were employed despite high cytotoxicity risks. While synthetic PKIs proved less toxic, they face significant drug resistance challenges. This review examines the progress in understanding protein kinases' role in cancer, their classification and modes of action since their discovery. To illuminate the path towards less toxic yet highly effective kinase inhibitors, this study analyzes the synthesis and modification of all FDA-approved natural product derived kinase inhibitors (NPDKIs) as well as those that failed clinical trials. By providing insights into successful and unsuccessful approaches, this review also aims to advance medicinal chemistry strategies for developing more effective and safer PKIs, potentially improving cancer treatment outcomes.

Preparation and Antibacterial Activity Evaluation of Daphnetin-Loaded Poloxamers/Polyvinylpyrrolidone Thermosensitive Hydrogels

Antibiotic misuse and bacterial resistance are pressing issues threatening public health. Natural plant extracts with bactericidal properties offer potential alternatives to reduce or replace antibiotic use. This study aims to develop a thermosensitive hydrogel containing daphnetin (DAP-TG) using poloxamers 407 (P407), polyvinylpyrrolidone (PVP), and poloxamers 188 (P188). We systematically evaluated the gel's antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), as well as its antibacterial mechanisms. By examining the gelation temperature and time, degradation time, and in vitro release performance of DAP-TG, we produced a sustained-release DAP-TG with a rapid phase transition at (31.6 ± 0.1) °C. Its structure was characterized through Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The results indicated that the DAP thermosensitive hydrogel was formed and presented a 3D network spatial structure. The biocompatibility of DAP-TG was explored through the hemolysis test and cytotoxicity test. The results indicated that DAP-TG possessed excellent biocompatibility. The antibacterial efficacy of DAP-TG against E. coli and S. aureus was assessed using minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), growth curve, and inhibition zone tests. Results showed that DAP-TG exhibited excellent antibacterial activity against both E. coli and S. aureus, with MIC values of 1.28 and 0.32 mg/mL. The antibacterial mechanism of DAP-TG was preliminarily explored through the investigation of bacterial cell content leakage, AKP leakage, membrane permeability, SEM, ROS production, and biofilm inhibition activity. DAP-TG induced irreversible damage to the cell membranes of E. coli and S. aureus, resulting in enhanced permeability, elevated ROS levels, and inhibited biofilm formation. Our study indicates that DAP-TG exhibits effective sustained-release and antibacterial properties against E. coli and S. aureus in vitro, making it a promising candidate for antibacterial applications in food and pharmaceutical products.

The molecular effects underlying the pharmacological activities of daphnetin

As an increasingly well-known derivative of coumarin, daphnetin (7,8-dithydroxycoumarin) has demonstrated various pharmacological activities, including anti-inflammation, anti-cancer, anti-autoimmune diseases, antibacterial, organ protection, and neuroprotection properties. Various studies have been conducted to explore the action mechanisms and synthetic methods of daphnetin, given its therapeutic potential in clinical. Despite these initial insights, the precise mechanisms underlying the pharmacological activities of daphnetin remain largely unknown. In order to address this knowledge gap, we explore the molecular effects from the perspectives of signaling pathways, NOD-like receptor protein 3 (NLRP3) inflammasome and inflammatory factors; and try to find out how these mechanisms can be utilized to inform new combined therapeutic strategies.

Coumarins and flavones with anti-inflammatory activity isolated from the branches and leaves of Daphne retusa

In this study, two new (1, 13) and fourteen known (2-12, 14-16) compounds were isolated from the branches and leaves of Daphne retusa. On the basis of chemical evidence and spectral data analysis (UV, ECD NMR, and HR-ESI-MS), the structures of new compounds were elucidated. Furthermore, all compounds have been tested for their inhibitory effects on NO production in LPS-induced RAW 264.7 cells, and compound 3 showed obvious inhibitory effect. Through target screening and molecular docking technology, potential binding targets for compound 3 to exert anti-inflammatory effects have been predicted.

The modulation of sirtuins by natural compounds in the management of cisplatin-induced nephrotoxicity

Cisplatin is a highly effective antitumor agent. However, its use is limited due to severe adverse effects, particularly nephrotoxicity, which occurs in approximately 30% of patients. There is a need for novel renoprotective compounds. Sirtuins play a vital role in various physiological and pathological processes such as oxidative stress, apoptosis, inflammation, and mitochondrial bioenergetics. It has been shown that sirtuins can exert a protective effect on cisplatin-induced acute kidney injury by targeting multiple signaling pathways. Besides, sirtuins not only did not reduce the anticancer effect of cisplatin but also increased it. Several natural compounds have been reported to inhibit cisplatin-mediated nephrotoxicity through sirtuin stimulation. These compounds exert their therapeutic effects on cisplatin-induced renal injury by targeting various signaling pathways including Sirt1/p53, Sirt1/NF-κb/p56, AMPK/Sirt1, Sirt1/PGC-1α, and/or by enhancing mitochondrial function.

Adera2.0: A Drug Repurposing Workflow for Neuroimmunological Investigations Using Neural Networks

Drug repurposing in the context of neuroimmunological (NI) investigations is still in its primary stages. Drug repurposing is an important method that bypasses lengthy drug discovery procedures and focuses on discovering new usages for known medications. Neuroimmunological diseases, such as Alzheimer's, Parkinson's, multiple sclerosis, and depression, include various pathologies that result from the interaction between the central nervous system and the immune system. However, the repurposing of NI medications is hindered by the vast amount of information that needs mining. We previously presented Adera1.0, which was capable of text mining PubMed for answering query-based questions. However, Adera1.0 was not able to automatically identify chemical compounds within relevant sentences. To challenge the need for repurposing known medications for neuroimmunological diseases, we built a deep neural network named Adera2.0 to perform drug repurposing. The workflow uses three deep learning networks. The first network is an encoder and its main task is to embed text into matrices. The second network uses a mean squared error (MSE) loss function to predict answers in the form of embedded matrices. The third network, which constitutes the main novelty in our updated workflow, also uses a MSE loss function. Its main usage is to extract compound names from relevant sentences resulting from the previous network. To optimize the network function, we compared eight different designs. We found that a deep neural network consisting of an RNN neural network and a leaky ReLU could achieve 0.0001 loss and 67% sensitivity. Additionally, we validated Adera2.0's ability to predict NI drug usage against the DRUG Repurposing Hub database. These results establish the ability of Adera2.0 to repurpose drug candidates that can shorten the development of the drug cycle. The workflow could be download online.

Daphnetin: A bioactive natural coumarin with diverse therapeutic potentials

Daphnetin (DAP), a coumarin derivative extracted from Daphne species, is biologically active phytochemical with copious bioactivities including anti-inflammatory, anti-oxidant, neuroprotective, analgesic, anti-pyretic, anti-malarial, anti-bacterial, anti-arthritic, neuroprotective, hepatoprotective, nephroprotective, and anti-cancer activities. A wide range of studies have been conducted exploring the significance and therapeutic potential of DAP. This study reviewed various databases such as NCBI, PubMed, Web of Science, Scopus and Google Scholar for published research articles regarding the sources, synthesis, and various bioactivities of DAP using different key words, including but not limited to "pharmacological activities," "sources," "neuroprotective effect," "synthesis," "cancer," "anti-inflammatory effect" of "daphnetin." Furthermore, this review encompasses both in-vivo and in-vitro studies on DAP for treating various diseases. A comprehensive review of the literature revealed that the DAP had a promising pharmacological and safety profile, and could be employed as a pharmaceutical moiety to treat a variety of illnesses including microbial infections, cancer, arthritis, hepatic damage, inflammation and neurological anomalies. The current review intends to provide an in-depth focus on all pharmacological activities and therapeutic approaches for the pharmaceutical and biomedical researchers.

Daphnetin, a Coumarin in Genus Stellera Chamaejasme Linn: Chemistry, Bioactivity and Therapeutic Potential

Coumarins is a huge family of phenolic compounds containing a common structure of 2 H -1-benzopyran-2-one. Nowadays, more than 1,300 natural-based coumarins have been identified in a variety of plants, bacteria and fungi, many of them exhibited promising biomedical performance. Daphnetin (7,8-dihydroxycoumarin) is a typical coumarin associated with a couple of bioactivities such as anti-cancer, antibacterial, anti-inflammatory and anti-arthritis. In the treatment of diseases, it has been verified that daphnetin has outstanding therapeutic effects on diabetes, arthritis, transplant rejection, cancer and even on central nervous system diseases. Herein, we summarized the chemical synthetic methodologies, bioactivities, therapeutic potentials and structure-activity relationships of daphnetin and its derivatives. Hopefully, this review would be beneficial for the discovery of new coumarin-based biomedicine in the near future.

Daphne odora Exerts Depigmenting Effects via Inhibiting CREB/MITF and Activating AKT/ERK-Signaling Pathways

Daphne odora, a blooming shrub, has been traditionally used for various medicinal purposes. However, information on its anti-melanogenic activity and dermal application is limited. In this study, the Daphne odora extract (DOE), with constituents including daphnetin, was used to investigate depigmenting activity and the underlying mechanism of Daphne odora. DOE inhibited in vitro and cellular tyrosinase activity in a dose-dependent manner, and reduced the α-MSH-induced melanin biosynthesis to a control level. The protein expressions of melanin synthesis-related enzymes were also significantly reduced by DOE. Moreover, DOE decreased the phosphorylation of cAMP-response element binding proteins (CREBs) induced by α-MSH in B16F10 cells, while it activated phosphorylated extra-cellular signal-regulated kinases (ERKs) and protein kinase B (AKT) expression. These results suggest that DOE might inhibit the melanogenesis signaling pathways by activating ERK- and AKT-signaling pathways to regulate the expression of CREB and MITF and its downstream pathways. Therefore, DOE could potentially be developed as a depigmenting agent.

Daphne jejudoensis Attenuates LPS-Induced Inflammation by Inhibiting TNF-α, IL-1β, IL-6, iNOS, and COX-2 Expression in Periodontal Ligament Cells

Periodontitis is a common disease involving inflammation and tissue destruction in the periodontal region. Although uncontrolled long-term inflammation in the gingiva may lead to loss of the periodontal ligament, treatments or preventive solutions for periodontitis are scarce. The aim of this study is to find anti-inflammatory material from a natural source that can be used to treat or protect against periodontitis. Daphne species (Thymelaeaceae) are important and popular components of traditional Chinese medicine and are used as anti-inflammatory agents. Daphne jejudoensis is an endemic plant that grows on Jeju Island and was identified as a new species in 2013. In this study, for the first time, we investigated the anti-inflammatory effect of D. jejudoensis leaf extract (DJLE) on human periodontal ligament cells. The gene expression levels of pro-inflammatory cytokines (interleukin-1β and 6 and tumor necrosis factor-α) and inflammation-inducible enzymes (inducible nitric oxide synthase and cyclooxygenase-2) were reduced after DJLE treatment with/without lipopolysaccharide stimulation. The findings of this study indicate that D. jejudoensis possesses anti-inflammatory activities, suggesting that DJLE may be a potential preventive and therapeutic agent for periodontitis.

Characteristic biflavonoids from Daphne kiusiana var. atrocaulis (Rehd.) F. Maekawa

Structurally diverse biflavonoids have attracted significant research interest for drug discovery over past decades. Biflavonoid oriented phytochemistry research on the stems of Daphne kiusiana var. atrocaulis (Rehd.) F. Maekawa was carried out, which resulted in the identification of ten major effective components (1-10), including the undescribed biflavonoids, daphnodorin Q (1), daphnodorin R (2) and flavane, daphnekiuslin A (10). The known structures were identified from this herb for the first time. Their structures were determined by combination of multiple spectroscopic data as well as calculated electronic circular dichroism (ECD). All the identified compounds were evaluated for the anti-neuroinflammatory effects. Compound 9 could inhibit the overactivation of BV-2 cells induced by lipopolysaccharide with IC₅₀ value at 26.32 μM.

Screening for Active Compounds Targeting Human Natural Killer Cell Activation Identifying Daphnetin as an Enhancer for IFN-γ Production and Direct Cytotoxicity

Natural killer (NK) cells are a potent weapon against tumor and viral infection. Finding active compounds with the capacity of enhancing NK cell effector functions will be effective to develop new anti-cancer drugs. In this study, we initially screened 287 commercially available active compounds by co-culturing with peripheral blood mononuclear cells (PBMCs). We found that five compounds, namely, Daphnetin, MK-8617, LW6, JIB-04, and IOX1, increased the IFN-γ⁺ NK cell ratio in the presence of IL-12. Further studies using purified human primary NK cells revealed that Daphnetin directly promoted NK cell IFN-γ production in the presence of IL-12 but not IL-15, while the other four compounds acted on NK cells indirectly. Daphnetin also improved the direct cytotoxicity of NK cells against tumor cells in the presence of IL-12. Through RNA-sequencing, we found that PI3K-Akt-mTOR signaling acted as a central pathway in Daphnetin-mediated NK cell activation in the presence of IL-12. This was further confirmed by the finding that both inhibitors of PI3K-Akt and its main downstream signaling mTOR, LY294002, and rapamycin, respectively, can reverse the increase of IFN-γ production and cytotoxicity in NK cells promoted by Daphnetin. Collectively, we identify a natural product, Daphnetin, with the capacity of promoting human NK cell activation via PI3K-Akt-mTOR signaling in the presence of IL-12. Our current study opens up a new potential application for Daphnetin as a complementary immunomodulator for cancer treatments.

Daphnetin inhibits spinal glial activation via Nrf2/HO-1/NF-κB signaling pathway and attenuates CFA-induced inflammatory pain

Daphnetin (7, 8-dihydroxycoumarin, DAPH), a coumarin derivative isolated from Daphne odora var., recently draws much more attention as a promising drug candidate to treat neuroinflammatory diseases due to its protective effects against neuroinflammation. However, itscontribution to chronic inflammatory pain is largely unknown. In the current work, we investigated the effects of DAPH in a murine model of inflammatory pain induced by complete Freund's adjuvant (CFA) and its possible underlying mechanisms. Our results showed that DAPH treatment significantly attenuated mechanical allodynia provoked by CFA. A profound inhibition of spinal glial activation, followed by attenuated expression levels of spinal pro-inflammatory cytokines, was observed in DAPH-treated inflammatory pain mice. Further study demonstrated that DAPH mediated negative regulation of spinal NF-κB pathway, as well as its preferential activation of Nrf2/HO-1 signaling pathway in inflammatory pain mice. This study, for the first time, indicated that DAPH might preventthe development of mechanical allodynia in mice with inflammatory pain. And more importantly, these data provide evidence for the potential application of DAPH in the treatment of chronic inflammatory pain.

Synthesis and anti-rheumatoid arthritis activities of 3-(4-aminophenyl)-coumarin derivatives

Rheumatoid arthritis is a chronic systemic disease characterised by an unknown aetiology of inflammatory synovitis. A large number of studies have shown that synoviocytes show tumour-like dysplasia in the pathological process of RA, and the changes in the expression of related cytokines are closely related to the pathogenesis of RA. In this thesis, a series of novel 3-(4-aminophenyl) coumarins containing different substituents were synthesised to find new coumarin anti-inflammatory drugs for the treatment of rheumatoid arthritis. The results of preliminary activity screening showed that compound 5e had the strongest inhibitory activity on the proliferation of fibroid synovial cells, and it also had inhibitory effect on RA-related cytokines IL-1, IL-6, and TNF-α. The preliminary mechanism study showed that compound 5e could inhibit the activation of NF-κB and MAPKs signal pathway. The anti-inflammatory activity of compound 5ein vivo was further determined in the rat joint inflammation model.

Regulatory effect of daphnetin on the balance of Th17 and Treg cells in the peripheral blood mononuclear cells from patients with unexplained recurrent pregnancy loss

Introduction

There has a close relationship between the balance of T helper 17 (Th17) cells and Foxp3+ regulatory T cells (Treg) and unexplained recurrent pregnancy loss (URPL). The present study is to investigate the regulatory effect of daphnetin, which is extracted from Daphne odora Var, on the balance of Th17 and Treg cells in the peripheral blood mononuclear cells (PBMCs) from patients with URPL.

Material and methods

PBMCs were isolated from 35 pregnant women with URPL and 35 women with normal early pregnancies, respectively and treated with daphnetin for three days. Flow cytometry was performed to measure the proportions of Th17 and Treg cells. The level of expression of IL-6, TGF-β1 and IL-2 were detected using enzyme-linked immunosorbent assay (ELISA) and the level of expression of FoxP3, RORγt, signal transducers and activators of transcriotion 3 (STAT3) and STAT5 were detected by RT-PCR.

Results

The concentrations of Th17-type cytokines IL-2 were significantly decreased in the URPL group after treatment (p < 0.01). Treg-type cytokines such as TGF-β1 and IL-6 were significantly increased after treatment (p < 0.01). At the same time, daphnetin may induce a decrease in the ratio of RORγt to Foxp3 and a Treg cell bias, which would be beneficial for pregnancy maintenance. Futhermore the expression level of STAT3 were higher in the URPL patients whereas STAT5 were lower than those in the control subjects.

Conclusions

In conclusion, daphnetin may have regulatory effect on the balance of Th17 and Treg cells in the peripheral blood mononuclear cells from patients with URPL.

Effect of locust bean gum-sodium alginate coatings incorporated with daphnetin emulsions on the quality of Scophthalmus maximus at refrigerated condition

In this study, the microbiological, physicochemical, and flavor changes of turbot (Scophthalmus maximus) coated with a composite active coating of locust bean gum (LBG) and sodium alginate (SA) supplemented with daphnetin emulsions (0.16, 0.32, 0.64 mg·mL^-1) were determined during 18 days of refrigerated storage (4 ± 1 °C). Results showed that LBG-SA coatings containing 0.32 mg·mL^-1 daphnetin emulsions could significantly lower the total viable count (TVC), psychrophiles, Pseudomonas spp. and H₂S-producing bacteria counts, and inhibit the productions of off-flavor compounds including the total volatile basic nitrogen (TVB-N), trimethylamine (TMA) and ATP-related compounds. 32 volatile compounds were identified by solid phase microextraction combined with gas chromatography-mass spectrometer method (SPME-GC/MS) during refrigerated storage and the treated turbot samples significantly lowered the relative content of fishy flavor compounds. Further, the LBG-SA coatings containing daphnetin could also delay the myofibril degradation of the turbot samples. These results indicated that the LBG-SA coatings with 0.32 mg·mL^-1 daphnetin were a potential alternative way to improve the quality of turbot during refrigerated storage.

Daphnetin suppresses experimental abdominal aortic aneurysms in mice via inhibition of aortic mural inflammation

Rupture of abdominal aortic aneurysm (AAA) is a devastating event that can be prevented by inhibiting the growth of small aneurysms. Therapeutic strategies targeting certain events that promote the development of AAA must be developed, in order to alter the course of AAA. Chronic inflammation of the aortic mural is a major characteristic of AAA and is related to AAA formation, development and rupture. Daphnetin (DAP) is a coumarin derivative with anti-inflammatory properties that is extracted from Daphne odora var. However, the effect of DAP on AAA development remains unclear. The present study investigated the effect of DAP on the formation and development of experimental AAAs and its potential underlying mechanisms. A mice AAA model was established by intra-aortic infusion of porcine pancreatic elastase (PPE), and mice were intraperitoneally injected with DAP immediately after PPE infusion. The maximum diameter of the abdominal aorta was measured by ultrasound system, and aortic mural changes were investigated by Elastica van Gieson (EVG) staining and immunohistochemical staining. The results demonstrated that DAP significantly suppressed PPE-induced AAA formation and attenuated the depletion of aortic medial elastin and smooth muscle cells in the media of the aorta. Furthermore, the density of mural macrophages, T cells and B cells were significantly attenuated in DAP-treated AAA mice. In addition, treatment with DAP resulted in a significant reduction in mural neovessels. These findings indicated that DAP may limit the formation and progression of experimental aneurysms by inhibiting mural inflammation and angiogenesis. These data confirmed the translational potential of DAP inclinical AAA inhibition strategies.

Daphnetin induces apoptosis in fibroblast-like synoviocytes from collagen-induced arthritic rats mainly via the mitochondrial pathway

Rheumatoid arthritis (RA) is a chronic, symmetric, systemic autoimmune disease. Because insufficient apoptosis of fibroblast-like synoviocytes (FLS) is an important characteristic of RA, promoting apoptosis is considered a potential therapeutic tool for treating RA. We have previously found that daphnetin (7,8-dihydroxycoumarin, DAP) has a pro-apoptotic effect on fibroblast-like synoviocytes from collagen-induced arthritis (CIA) rats. In the present study, we further investigated the mechanisms of DAP-induced apoptosis in CIA-FLS. CIA-FLS were incubated with DAP for 48 h in the presence or absence of caspase inhibitors, including inhibitors of caspase-3, caspase-8, or caspase-9 or a pan-caspase inhibitor; then, a series of experiments were performed to evaluate the mechanisms of DAP-induced apoptosis. Our results showed that DAP markedly decreased cell viability and induced the apoptosis of CIA-FLS along with typical morphological and ultrastructural changes; moreover, DAP increased FasL, cytochrome c (Cyt-c), Bax, caspase-3, caspase-8, and caspase-9 mRNA expression and Bax, caspase-3, caspase-8, and caspase-9 protein expression. In contrast, DAP decreased Bcl-2 mRNA and protein expression and promoted the release of Cyt-c from the mitochondria into the cytosol; these effects were attenuated to varying degrees by pre-treatment with caspase inhibitors, especially with caspase-3 or caspase-9 inhibitors or a pan-caspase inhibitor. In conclusion, the current findings demonstrate that the DAP-induced apoptosis of CIA-FLS occurred mainly via a caspase-dependent pathway, in particular the mitochondrial pathway, and that the Bax/Bcl-2 ratio was involved in this process. Thus, DAP may be a potential therapeutic agent for RA.

Chinese Herbal Formula, Huayu Tongbi Fang, Attenuates Inflammatory Proliferation of Rat Synoviocytes Induced by IL-1β by Regulating Proliferation and Differentiation of T Lymphocytes

The inflammatory proliferation of fibroblast-like synoviocytes (FLSs) and functional imbalances in T lymphocytes play critical roles in the pathogenesis of rheumatoid arthritis (RA). The clinical efficacy of Huayu Tongbi Fang (HYTB, a traditional herbal formula) in RA treatment has been validated. In this study, we aimed to explore the regulatory mechanisms of HYTB on the proliferation and differentiation of T lymphocytes, and the inhibitory effect of HYTB on inflammatory proliferation of FLSs. The RCS-364 (Rat FLSs) cells were cocultured with rat splenic lymphocytes that were induced by interleukin-1β in Transwell chambers. After freeze-dried HYTB powder treatment, the percentage of T-cell subset and apoptosis rates of FLSs were measured using flow cytometry. Furthermore, protein expression of key molecules of NF-κB and JAK/STAT signaling pathways was quantified using Western blot. The granulocyte-macrophage colony-stimulating factor (GM-CSF) was measured using enzyme-linked immunosorbent assay. The results showed that HYTB could inhibit the inflammatory proliferation of FLSs through inducing cell apoptosis. Additionally, HYTB treatment could intervene in the proliferation and differentiation of T lymphocytes and regulate protein expression of key molecules in NF-κB and JAK/STAT cell signaling pathways. Moreover, it could inhibit FLS activation by suppressing GM-CSF production by T cells and FLSs. Therefore, the HYTB formula should be used as a traditional medicine against RA in modern complementary and alternative therapies.

Daphnetin Ameliorates Experimental Autoimmune Encephalomyelitis Through Regulating Heme Oxygenase-1

To assess the potential role of daphnetin, a clinically used anti-inflammatory agent, on the development of the inflammatory and neurodegenerative disease, we investigated its immune regulatory function in a murine model of experimental autoimmune encephalomyelitis (EAE). Significantly, lower levels of pro-inflammatory cytokines including interleukin (IL)-17, interferon-γ, Il6, Il12a, and Il23a were observed in brains of daphnetin-treated EAE mice, compared with those in control littermates. We also confirmed that daphnetin suppressed the production of IL-1β, IL-6, and tumor necrosis factor-α in lipopolysaccharide-stimulated mouse BV2 microglial cells. Mechanistically, heme oxygenase-1 (HO-1), a canonical anti-oxidant and anti-inflammatory factor, was found to be substantially induced by daphnetin treatment in BV2 cells. Also, a significantly higher level of HO-1, accompanied by a decreased level of malondialdehyde, was observed in daphnetin-treated EAE mice. More importantly, the deletion of HO-1 in BV2 microglia largely abrogated daphnetin-mediated inhibition of the inflammatory response. Together, our data demonstrate that daphnetin has an anti-inflammatory and neuroprotective role during the pathogenesis of EAE, which is partially at least, dependent on its regulation of HO-1.

Daphne giraldii Nitsche (Thymelaeaceae): Phytochemistry, pharmacology and medicinal uses

Daphne giraldii Nitsche., a member of the genus Daphne (Thymelaeaceae), is a deciduous shrub with mild toxicity. Its rhizome bark, generally called 'Zushima' in Chinese, has many medicinal folkloric uses and good therapeutic effects. Previous studies investigating the chemical constituents and pharmacological activities of D. giraldii have focused on several major classes of compounds, such as coumarins, lignans and flavonoids, especially the interesting enantiomeric flavans. Extracts and pure compounds of D. giraldii were found to possess anti-inflammatory, anti-nociceptive, cytotoxicity, antimalarial, immunomodulating, sedative and hypnotic effects. They have also been reported to influence the cardiovascular functions and blood activities. This comprehensive review will describe the advances in the phytochemistry, pharmacology, medicinal uses and clinical applications of D. giraldii and its formulations covering the literature published from 1970 to 2018. Almost half of the reviewed studies were originally published in non-English languages (mainly in Chinese). Collectively, the aim of this article is to open new avenues for further in-depth pharmacological studies on D. giraldii.

Daphnetin attenuates LPS-induced osteolysis and RANKL mediated osteoclastogenesis through suppression of ERK and NFATc1 pathways

Aseptic prosthetic loosening and periprosthetic infection resulting in inflammatory osteolysis is a leading complication of total joint arthroplasty (TJA). Excessive bone destruction around the bone and prosthesis interface plays a key role in the loosening prostheses leading to revision surgery. The bacterial endotoxins or implant-derived wear particles-induced inflammatory response is the major cause of the elevated osteoclast formation and activity. Thus, agents or compounds that can attenuate the inflammatory response and/or inhibit the elevated osteoclastogenesis and excessive bone resorption would provide a promising therapeutic avenue to prevent aseptic prosthetic loosening in TJA. Daphnetin (DAP), a natural coumarin derivative, is clinically used in Traditional Chinese Medicine for the treatment of rheumatoid arthritis due to its anti-inflammatory properties. In this study, we report for the first time that DAP could protect against lipopolysaccharide-induced inflammatory bone destruction in a murine calvarial osteolysis model in vivo. This protective effect of DAP can in part be attributed to its direct inhibitory effect on RANKL-induced osteoclast differentiation, fusion, and bone resorption in vitro. Biochemical analysis found that DAP inhibited the activation of the ERK and NFATc1 signaling cascades. Collectively, our findings suggest that DAP as a natural compound has potential for the treatment of inflammatory osteolysis.

Daphnetin prevents methicillin-resistant Staphylococcus aureus infection by inducing autophagic response

The bacterial pneumonia caused by methicillin-resistant Staphylococcus aureus (MRSA) is a potentially fatal disease, featured with extensive infection, inflammation, and airway dysfunction. With the increasing emerging of drug-resistant strains, new therapeutic strategies beyond canonical antibiotic treatment are pressingly needed. Daphnetin (DAPH) is a natural coumarin derivative with anti-inflammation, anti-microorganism and anti-oxidative properties. However, the protective effect of DAPH on S. aureus-caused pneumonia and the mechanism involved are never explored. Here we show that DAPH treatment conferred substantial protection against S. aureus-induced pneumonia, characterized by the reduced inflammatory responses, the augmented bacterial clearance and the alleviated tissue damage. Our study indicates that DAPH significantly enhanced mTOR-dependent autophagic pathway, leading to the boosted microphage bactericidal activity and the suppressed inflammatory responses. Inhibition of autophagic pathway therefore largely abolished DAPH-elicited repression of inflammatory response and macrophage anti-bacterial capability. Together, we herein not only identify a novel, natural agent to combat bacterial pneumonia, but also underscore the significance of autophagic pathway in orchestrating antimicrobial and anti-inflammatory responses, which may have important implication for the treatment of the infectious diseases, particularly that caused by obstinate, antibiotic-resistant pathogens such as MRSA.

Daphnetin ameliorates experimental colitis by modulating microbiota composition and Treg/Th17 balance

Inflammatory bowel diseases (IBDs) are characterized by chronic pathologies associated with extensive gut dysbiosis and intestinal inflammation. Hence, endeavors to improve the inflammatory pathology by manipulating gut microbiota are ongoing. Daphnetin (DAPH) is a coumarin derivative extracted from Daphne odora var with anti-inflammatory and immune-regulatory properties that has been widely used in treating inflammatory disorders. Herein, we showed that DAPH remarkably alleviated experimental colitis by reducing colonic inflammation, improving colonic integrity, and reestablishing immune and metabolic homeostasis in the inflicted intestines. Our analysis showed that DAPH modified the composition of gut microbiota and altered the metabolic profiles in dextran sulfate sodium-treated mice. In particular, this agent significantly elevated the abundance of short-chain fatty acid (SCFA)-producing gut microbiota, causatively related with the enhanced development of T_reg cells and the reduced proinflammatory T_h17 cell differentiation. More critically, the protective effect of DAPH was shown to be transmissible among colitic mice through cohousing or fecal microbiota transplantation, further substantiating the importance of SCFA-producing gut microbiota in DAPH action. We thus for the first time reveal the potential of DAPH in resetting the gut microbiome and reestablishing immune homeostasis in colitic mice, which may have clinical implications for treating IBD.-Ji, J., Ge, X., Chen, Y., Zhu, B., Wu, Q., Zhang, J., Shan, J., Cheng, H., Shi, L. Daphnetin ameliorates experimental colitis by modulating microbiota composition and T_reg/T_h17 balance.

The phytochemistry, pharmacokinetics, pharmacology and toxicity of Euphorbia semen

ETHNOPHARMACOLOGICAL RELEVANCE

Euphorbia semen, the dried and ripe seed of Euphorbia lathyris Linnaeus, is widely cultivated for traditional medicine use. This semen is used to expel water, help with phlegm retention, promote blood circulation, remove blood stasis, cure tinea and scabies, and treat amenorrhea, snakebites, terminal schistosomiasis, anuria and constipation.

AIM OF THE REVIEW

This review provides updated, comprehensive and categorized information on the local and traditional uses, phytochemistry, pharmacokinetics, pharmacological activities and toxicity of Euphorbia semen. Future research to deepen the recognition and utilization of Euphorbia semen is proposed.

MATERIALS AND METHODS

This article conducted a literature review on information about Euphorbia semen in multiple Internet databases, including PubMed, Web of Science, Wiley, Science Direct, Elsevier, ACS publications, SciFinder, Google Scholar and China National Knowledge Internet, until March of 2018. In this manuscript, a number of books, PhD and MSc dissertations, and Chinese Pharmacopeia were also used as references.

RESULTS

Approximately 240 chemical constituents have been isolated and identified from Euphorbia semen, namely, diterpenoids, coumarins, flavonoids, fatty acids, amino acids, and steroids. Pharmacokinetic study focused on investigating absorption, distribution, metabolism and excretion (ADME). The chemical constituents have extensive pharmacological effects, such as diuresis and anti-hyperuricaemia, anti-inflammation, antiviral, anticancer, antioxidant, antipigmentation, anti-platelet aggregation and anti-allergic activities, as well as hepatoprotection and neuroprotection. The toxicity of Euphorbia semen, including acute toxicity, target organ irritation and cocareinogenic effects, have been reported, and the detoxification methods are reviewed.

CONCLUSION

Euphorbia semen has extensive pharmacological activity and excellent clinical value, along with intense intestinal irritation. Although plenty of chemical constituents have been isolated and identified, the exact pharmacological and toxicological mechanisms still need to be explored.

Selection and Investigation of a Primate Model of Spontaneous Degenerative Knee Osteoarthritis, the Cynomolgus Monkey (Macaca Fascicularis)

BACKGROUND The aim of this study was to identify a primate model of degenerative knee osteoarthritis (KOA) that may be more relevant for research studies on degenerative KOA in humans. MATERIAL AND METHODS Sixteen specific-pathogen-free (SPF) male cynomolgus monkeys (Macaca fascicularis) were divided into group A (n=8), an old group (22.0-25.3 years of age), and group B (n=8), a young group (3.0-5.2 years of age). For each primate, the behavior was observed, knee circumference was measured, knee joint X-rays were performed, and peripheral blood white blood cell (WBC) counts were measured, and the Kellgren and Lawrence (K-L) system was used for the classification of osteoarthritis. An enzyme-linked immunoassay (ELISA) was performed on knee joint fluid to measure levels of interleukin (IL)-1β, transforming growth factor (TGF)-β1, and matrix metalloproteinase (MMP)13. Changes in articular cartilage were evaluated using the Brittberg score and the Mankin histopathology grading score, respectively. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) and Western blot were used to measure the expression of the NOTCH3, JAG1, and ACAN genes in knee cartilage specimens, and the findings in the two groups of primates were compared. RESULTS Seven old aged primates in group A were compared with group B, and showed significant differences in WBC count, synovial fluid IL-1β, TGF-β1, and MMP13 levels, expression levels of the NOTCH3, JAG1, and ACAN genes in knee cartilage specimens, and in the Brittberg and Mankin scores (all, P<0.05). CONCLUSIONS Cynomolgus monkeys (Macaca fascicularis) might be a model for age-related degenerative KOA.

Toll-Like Receptor 2 Signaling and Current Approaches for Therapeutic Modulation in Synucleinopathies

The innate immune response in the central nervous system (CNS) is implicated as both beneficial and detrimental to health. Integral to this process are microglia, the resident immune cells of the CNS. Microglia express a wide variety of pattern-recognition receptors, such as Toll-like receptors, that detect changes in the neural environment. The activation of microglia and the subsequent proinflammatory response has become increasingly relevant to synucleinopathies, including Parkinson's disease the second most prevalent neurodegenerative disease. Within these diseases there is evidence of the accumulation of endogenous α-synuclein that stimulates an inflammatory response from microglia via the Toll-like receptors. There have been recent developments in both new and old pharmacological agents designed to target microglia and curtail the inflammatory environment. This review will aim to delineate the process of microglia-mediated inflammation and new therapeutic avenues to manage the response.

Effects of daphnetin combined with Bcl2‑siRNA on antiapoptotic genes in synovial fibroblasts of rats with collagen‑induced arthritis

The aim of the present study was to investigate the effects of daphnetin combined with B cell lymphoma 2 (Bcl2)‑targeted small interfering (si)RNA (si‑Bcl2) on antiapoptotic genes in fibroblast‑like synoviocytes (FLS) in rats with collagen II‑induced arthritis (CIA). The roles of si‑Bcl2 and daphnetin were determined by measuring the expression levels of Bcl2. Protein and mRNA expression levels of Bcl2 in FLS were determined by flow cytometry and reverse transcription‑quantitative polymerase chain reaction. Apoptosis of FLS was also determined by flow cytometry. It was revealed that treatment with si‑Bcl2 or daphnetin alone resulted in downregulation of Bcl2 mRNA and protein expression. In addition, the mRNA expression levels of the signal transducer and activator of transcription 3 (STAT3), which transcriptionally regulates the activity of mitochondria, were reduced. The combination of si‑Bcl2 and daphnetin exhibited an enhanced effect on rheumatoid arthritis FLS (RAFLS), in which the apoptotic rate was significantly higher than either treatment alone. The results suggested that si‑Bcl combined with daphnetin may have an enhanced effect in promoting apoptosis of RAFLS derived from CIA rats, and a possible underlying molecular mechanism may function through the downregulation of Bcl2 expression and STAT3, which is located upstream of Bcl2 in the mitochondrial apoptotic pathway. The results of the present study are expected to provide theoretical and experimental basis for the treatment of RA and the medicinal development of daphnetin combined siRNA.

Anti-arthritic activity of ethanol extract of Claoxylon indicum on Freund's complete adjuvant-induced arthritis in mice

BACKGROUND

Claoxylon indicum Hassk. (Euphorbiaceae), named Diu Le Bang, have functions of dehumidification and relieving swelling pain, and is used as a folk medicine to treat Rheumatoid arthritis (RA), lumbocrural pain and foot edema in the south of China. The aim of the present study was to investigate the anti-arthritic activity of the ethanol extract of Claoxylon indicum (CIE) on mice with adjuvant induced joint arthritis.

METHODS

Adjuvant arthritis was induced in mice by subcutaneous injection of complete Freund's adjuvant into the plantar surface of right hind paw. Arthritis severity was evaluated by arthritic score, hind paws oedema and spleen index, and histological examinations. Serum samples were collected for determination of malondialdehyde (MDA) and alkaline phosphatase (ALP) levels. The expression of interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) in the specimens of knee joints was determined by standard immunohistochemical techniques.

RESULTS

CIE administration (0.4 and 0.8 g/kg) suppressed the inflammatory responses in the joints of adjuvant-induced arthritis (AIA) mice, suggested by the modulatory effects on paw swelling, hyperplasia of lymphatic tissues and synovial membrane. It also decreased the levels of MDA and ALP in serum and downregulated the expression of IL-1β and TNF-α in the arthritic joints of AIA mice.

CONCLUSION

These results suggested that CIE possessed substantial anti-arthritic activity due to immumodepression and regulation of cytokines. CIE may be a potential candidate for the treatment of RA.

Daphnetin Protects against Cerebral Ischemia/Reperfusion Injury in Mice via Inhibition of TLR4/NF-κB Signaling Pathway

Growing evidences indicate that immune-mediated mechanisms contribute to the development of cerebral ischemia/reperfusion (I/R) injury. Daphnetin (DAP) is a coumarin derivative extracted from Daphne odora var., which displays anti-inflammatory properties. However, the effect of DAP on cerebral I/R injury is not yet clear. Recent studies have demonstrated that TLR4/NF-κB signaling pathway takes part in the damaging inflammatory process of cerebral I/R injury. The present study aimed to investigate the effect of DAP on cerebral I/R injury in vivo and its possible mechanisms. DAP was administered before middle cerebral artery occlusion and reperfusion in mice. The neurological scores, cerebral infarct sizes, the levels of inflammatory cytokines, apoptotic neural cells, and the levels of TLR4, NF-κB p65, and IκBα were estimated. The results showed that an obvious improvement of neurological scores and infarct sizes was observed in DAP-treated mice after MCAO/R. DAP treatment decreased the overexpression of TNF-α, IL-1β, and IL-6 and attenuated neural cells apoptosis. Moreover, DAP treatment decreased the TLR4 expression, IκB-α degradation, and nuclear translocation of NF-κB. Taken together, our results suggested that DAP exerted neuroprotective and anti-inflammatory effects on cerebral I/R injury. The potential mechanism was involved in the inhibition of TLR4/NF-κB mediated inflammatory signaling pathway.

Natural and Synthetic Coumarins with Effects on Inflammation

In this review, we will present the different aspects of coumarins and derivatives, from natural origins or synthetically prepared, and their action on inflammation. Coumarins and also furo- and pyranocoumarins are found in many different plants. These compounds are very often investigated for antioxidant properties. Other biological properties are also possible and anti-inflammation activity is one of these. As coumarins are also available quite easily via synthesis, natural ones can be prepared this way but derivatives with special substituents are also feasible. A review on the same topic appeared in 2004 and our contribution will take into account everything published since then.

Daphnetin Alleviates Experimental Autoimmune Encephalomyelitis via Regulating Dendritic Cell Activity

AIMS

Daphnetin, a coumarin derivative extracted from Daphne odora var. marginata, has been reported to have antiinflammatory and immunosuppressive properties. Our previous study indicated that it was able to remarkably suppress the neuroinflammation and suggested its potential application in treating neuroinflammatory diseases. Multiple sclerosis (MS), a Th cell-mediated autoimmune disease, is the most common inflammatory demyelinating disease of the central nervous system (CNS). We examined whether daphnetin treatment can protect mice against experimental autoimmune encephalomyelitis (EAE), an animal model for MS.

METHODS

To assess the effect of daphnetin in neuroinflammatory diseases, the EAE mice were established and treated with daphnetin at 8 mg/kg for 28 days. The severity of neuroinflammation and demyelination in the spinal cords was examined histopathologically. Infiltration of CD4(+) T cells into the CNS was assessed by immunohistochemistry, and the cytokine production was determined by ELISA. Meanwhile, the effect of daphnetin on the activity of dendritic cells (DCs) was evaluated, as assessed by DCs' capability to express surface markers, secrete cytokines, and activate naïve CD4(+) T cells. Furthermore, we explored the molecular mechanisms whereby DAPH regulated DCs' activity and thereby CD4(+) T cell responses.

RESULTS

The administration of daphnetin markedly alleviated the clinical symptoms of EAE and reduced the CNS inflammation and demyelination in experimental mice. Th1 and Th17 cell responses were profoundly repressed in daphnetin-treated EAE mice. Mechanistically, daphnetin treatment significantly repressed the activation, maturation, and antigen-presenting capability of DCs. NF-κB signaling was significantly reduced in daphnetin-treated DCs, along with a concomitant induction of heme oxygenase-1, a negative regulator of inflammatory signaling.

CONCLUSIONS

Our findings for the first time demonstrate the property of daphnetin in regulating DCs' function and subsequently Th development. Given the low or absent toxicity associated with daphnetin, our data may suggest a novel safe and effective approach to control autoimmune neuroinflammation.

Methylation, Glucuronidation, and Sulfonation of Daphnetin in Human Hepatic Preparations In Vitro: Metabolic Profiling, Pathway Comparison, and Bioactivity Analysis

Our previous study demonstrated that daphnetin is subject to glucuronidation in vitro. However, daphnetin metabolism is still poorly documented. This study aimed to investigate daphnetin metabolism and its consequent effect on the bioactivity. Metabolic profiles obtained by human liver S9 fractions and human hepatocytes showed that daphnetin was metabolized by glucuronidation, sulfonation, and methylation to form 6 conjugates which were synthesized and identified as 7-O-glucuronide, 8-O-glucuronide, 7-O-sulfate and 8-O-sulfate, 8-O-methylate, and 7-O-suflo-8-O-methylate. Regioselective 8-O-methylation of daphnetin was investigated using in silico docking calculations, and the results suggested that a close proximity (2.03 Å) of 8-OH to the critical residue Lysine 144 might be the responsible mechanism. Compared with glucuronidation and sulfonation pathways, the methylation of daphnetin had a high clearance rate (470 μL/min/mg) in human liver S9 fractions and contributed to a large amount (37.3%) of the methyl-derived metabolites in human hepatocyte. Reaction phenotyping studies showed the major role of SULT1A1, -1A2, and -1A3 in daphnetin sulfonation, and soluble COMT in daphnetin 8-O-methylation. Of the metabolites, only 8-O-methyldaphnetin exhibited an inhibitory activity on lymphocyte proliferation comparable to that of daphnetin. In conclusion, methylation is a crucial pathway for daphnetin clearance and might be involved in pharmacologic actions of daphnetin in humans.

Immunosuppressive effect of Chinese medicine on T helper 17 cells

T helper (Th)17 cells have been proposed to play important roles in several human diseases. The literatures about Chinese medicine studies, which related to inhibiting Th17, were reviewed, and the Chinese medicine which could inhibit Th17 cells was summarized in this paper.

Anti-inflammatory and protective properties of daphnetin in endotoxin-induced lung injury

Uncontrolled inflammatory responses cause tissue injury and severe immunopathology. Pharmacological interference of intracellular pro-inflammatory signaling may confer a therapeutic benefit under these conditions. Daphnetin, a natural coumarin derivative, has been used to treat inflammatory diseases including bronchitis. However, the protective effect of daphnetin in inflammatory airway disorders has yet to be determined, and the molecular basis for its anti-inflammatory properties is unknown. This paper shows that daphnetin treatment conferred substantial protection from endotoxin-induced acute lung injury (ALI), in parallel with reductions in the production of inflammatory mediators, symptoms of airway response, and infiltration of inflammatory cells. Further studies indicate that activation of macrophage and human alveolar epithelial cells in response to lipopolysaccharide (LPS) was remarkably suppressed by daphnetin, which was related to the down-regulation of NF-κB-dependent signaling events. Importantly, this study demonstrates that TNF-α-induced protein 3 (TNFAIP3), also known as A20, was significantly induced by daphnetin, which appeared to be largely responsible for the down-regulation of NF-κB activity through modulation of nondegradative TRAF6 ubiquitination. Accordingly, the deletion of TNFAIP3 in primary macrophages reversed daphnetin-elicited inhibition of immune response, and the beneficial effect of daphnetin in the pathogenesis of ALI was, partially at least, abrogated by TNFAIP3 knockdown. These findings demonstrate the anti-inflammatory and protective functions of daphnetin in endotoxin-induced lung inflammation and injury and also reveal the key mechanism underlying its action in vitro as well as in vivo.

Therapeutic effect of daphnetin on the autoimmune arthritis through demethylation of proapoptotic genes in synovial cells

Background

We have previously reported that dephnetin is therapeutically effective in the treatment of rheumatoid arthritis (RA) in collagen-induced arthritis (CIA) rat model. However, the molecular mechanism and the effect of daphnetin on demethylating proapoptotic genes in the synovial cells remains further clarified. This study may provide a deeper insight into the medicinal application of daphnetin as a treatment for RA.

Methods

(1) The proliferation inhibition of CIA rat synovial cells was determined by an MTT (3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenyterazoliumromide) assay; (2) Methylation specific PCR (MSP) was used to measure the methylation of the proapoptotic genes DR3 (death receptor 3), PDCD5 (programmed cell death 5), FasL and p53; (3) Real time-PCR was performed to determine the mRNA expression of DR3, PDCD5, FasL, p53 and DNA methyltransferases (DNMTs) DNMT1, DNMT3a and DNMT3b; (4) Flow cytometry was applied to detect the protein expression of the DR3, PDCD5, FasL and p53; (5) The apoptotic rate of synovial cells was assessed by flow cytometry with Annexin V and propidium iodide (PI); (6) Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the changes of CIA rat synovial cell structure.

Results

(1) In the range of 1.25 μg/mL to 40 μg/mL, daphnetin and 5-aza-dc had a dose-dependent and time-dependent degree of inhibition to the CIA rat synovial cells. (2) Daphnetin and 5-aza-dc had a demethylating role on the proapoptotic genes DR3, PDCD5, FasL and p53 of CIA rat synovial cells. (3) Daphnetin and 5-aza-dc decreased the gene expression of methyltransferases DNMT1, DNMT3a and DNMT3b, and increased expression of proapoptotic genes DR3, PDCD5, FasL and p53, which translated into an increased protein expression of DR3, PDCD5, FasL and p53. (4) Daphnetin and 5-aza-dc changed the structure of CIA rat synovial cells to show apoptotic changes and increased the rate of apoptosis.

Conclusions

Daphnetin can reduce the expression of DNMT1, DNMT3a and DNMT3b, which could result in the proapoptotic genes DR3, PDCD5, FasL and p53 being demethylated. Therefore, daphnetin can increase proapoptotic gene and protein expression resulting in structural apoptotic changes and an increase in early and late CIA rat synovial cell apoptosis.

Neuroprotective effects of daphnetin against NMDA receptor-mediated excitotoxicity

The accumulation of glutamate can excessively activate the N-methyl-d-aspartate (NMDA) receptors and cause excitotoxicity. Daphnetin (Dap), a coumarin derivative, is a protein kinase inhibitor that exhibits antioxidant and neuroprotective properties. However, little is known about the neuroprotective effects of Dap on glutamate-induced excitotoxicity. We evaluated the neuroprotective activities in the primary cultured cortical neurons against NMDA-induced excitotoxicity. Pretreatment with Dap significantly prevented NMDA-induced neuronal cell loss. Dap significantly inhibited the neuronal apoptosis by regulating balance of Bcl-2 and Bax expression. Furthermore, pretreatment of Dap reversed the up-regulation of NR2B-containing NMDA receptors and inhibited the intracellular Ca²⁺ overload induced by NMDA exposure. In addition, Dap prevented cerebral ischemic injury in mice induced via a 2 h middle cerebral artery occlusion and a 24 h reperfusion in vivo. The findings suggest that Dap prevents the excitotoxicity through inhibiting the NR2B-containing NMDA receptors and the subsequent calcium overload in cultured cortical neurons.

Induction of Nur77-dependent apoptotic pathway by a coumarin derivative through activation of JNK and p38 MAPK

Coumarins are plant-derived natural products with a broad range of known pharmacological activities including anticancer effects. However, the molecular mechanisms by which this class of promising compounds exerts their anticancer effects remain largely unknown. We report here that a furanocoumarin named apaensin could effectively induce apoptosis of cancer cells through its activation of Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK). Apoptosis induction by apaensin in cancer cells was suppressed by chemical inhibitors of JNK and p38 MAPK. Inhibition of the expression of orphan nuclear receptor Nur77 by small interfering RNA (siRNA) approach also abrogated the death effect of apaensin. Molecular analysis demonstrated that JNK activation was required for the nuclear export of Nur77, a known apoptotic event in cancer cells. Although p38 MAPK activation was not involved in Nur77 nuclear export, it was essential for Nur77 mitochondrial targeting through induction of Nur77 interaction with Bcl-2, which is also known to convert Bcl-2 from an antiapoptotic to a proapoptotic molecule. Together, our results identify a new natural product that targets orphan nuclear receptor Nur77 through its unique activation of JNK and p38 MAPK and provide insight into the complex regulation of the Nur77-Bcl-2 apoptotic pathway.

Daphnetin attenuates microglial activation and proinflammatory factor production via multiple signaling pathways

Daphnetin, a natural coumarin derivative, is known to display anti-inflammatory properties and has been used to treat inflammatory diseases. A novel finding suggested that daphnetin might have a neuroprotective effect in stressed mice, leading us to explore its role in the microglial inflammatory response, as well as its underlying mechanism of action. We found that the production of pro-inflammatory mediators, including interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), induced by lipopolysaccharide (LPS) or β-amyloid (Aβ) was significantly suppressed by daphnetin in a dose-dependent manner in BV2 microglia. Also, daphnetin inhibited LPS-induced nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression and NO formation by microglia. Mechanistically, daphnetin blunted the transcriptional activity of nuclear factor-kappa B (NF-κB), which was associated with the down-regulation of the phosphorylation and nuclear translocation of RelA/p65. Inhibitors of kappa B (IκB) phosphorylation and degradation were also affected by daphnetin, which was likely due to the reduced activation of IκB kinase (IKK). Additionally, LPS-induced activation of mitogen-activated protein kinases (MAPKs), such as extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 MAPK, were, to a varying extent, altered by daphnetin. Finally, daphnetin blocked phosphatidylinositol-3 kinase (PI-3K)/protein kinase B (Akt) signaling in LPS-activated microglia, which appeared to at least partially account for the reduction in NF-κB transcriptional activity. Thus, daphnetin inhibited microglial activation and proinflammatory responses by modulating a series of intracellular signaling pathways, including IKK/IκB, MAPKs and PI-3K/Akt.

Toll-like receptor-mediated IRE1α activation as a therapeutic target for inflammatory arthritis

In rheumatoid arthritis (RA), macrophage is one of the major sources of inflammatory mediators. Macrophages produce inflammatory cytokines through toll-like receptor (TLR)-mediated signalling during RA. Herein, we studied macrophages from the synovial fluid of RA patients and observed a significant increase in activation of inositol-requiring enzyme 1α (IRE1α), a primary unfolded protein response (UPR) transducer. Myeloid-specific deletion of the IRE1α gene protected mice from inflammatory arthritis, and treatment with the IRE1α-specific inhibitor 4U8C attenuated joint inflammation in mice. IRE1α was required for optimal production of pro-inflammatory cytokines as evidenced by impaired TLR-induced cytokine production in IRE1α-null macrophages and neutrophils. Further analyses demonstrated that tumour necrosis factor (TNF) receptor-associated factor 6 (TRAF6) plays a key role in TLR-mediated IRE1α activation by catalysing IRE1α ubiquitination and blocking the recruitment of protein phosphatase 2A (PP2A), a phosphatase that inhibits IRE1α phosphorylation. In summary, we discovered a novel regulatory axis through TRAF6-mediated IRE1α ubiquitination in regulating TLR-induced IRE1α activation in pro-inflammatory cytokine production, and demonstrated that IRE1α is a potential therapeutic target for inflammatory arthritis.

Synthesis and biological evaluation of Germanium(IV)-polyphenol complexes as potential anti-cancer agents

Germanium (Ge) is considered to play a key role in the pharmacological effects of some medicinal plants. Here, two new Ge(IV)-polyphenol complexes were synthesized and measured for their potential biological activities. The results indicated that these Ge(IV)-polyphenol complexes possessed great anti-oxidative activities, both showing stronger hydroxyl scavenging effects than their corresponding ligands. We also demonstrated the strong intercalating abilities of Ge(IV)-polyphenol complexes into calf thymus-DNA molecules. In addition, these two Ge(IV)-polyphenol complexes showed strong proliferative inhibition effect on HepG2 cancer cells. Moreover, the morphological changes in HepG2 cells induced by Ge(IV)-polyphenol complexes were detected by atomic force microscopy. All these results collectively suggested that Ge(IV)-polyphenol complexes could be served as promising pharmacologically active substances against cancer treatment.

Naturally derived anti-inflammatory compounds from Chinese medicinal plants

ETHNOPHARMACOLOGICAL RELEVANCE

Though inflammatory response is beneficial to body damage repair, if it is out of control, it can produce adverse effects on the body. Although purely western anti-inflammatory drugs, orthodox medicines, can control inflammation occurrence and development, it is not enough. The clinical efficacy of anti-inflammation therapies is unsatisfactory, thus the search for new anti-inflammation continues. Chinese Material Medica (CMM) remains a promising source of new therapeutic agents. CMM and herbal formulae from Traditional Chinese Medicine (TCM), unorthodox medicines, play an improtant anti-inflammatory role in multi-targets, multi-levels, and multi-ways in treating inflammation diseases in a long history in China, based on their multi-active ingredient characteristics. Due to these reasons, recently, CMM has been commercialized as an anti-inflammation agent which has become increasingly popular in the world health drug markets. Major research contributions in ethnopharmacology have generated vast amount of data associated with CMM in anti-inflammtion aspect. Therefore, a systematic introduction of CMM anti-inflammatory research progress is of great importance and necessity.

AIM OF THE STUDY

This paper strives to describe the progress of CMM in the treatment of inflammatory diseases from different aspects, and provide the essential theoretical support and scientific evidence for the further development and utilization of CMM resources as a potential anti-inflammation drug through a variety of databases.

MATERIAL AND METHODS

Literature survey was performed via electronic search (SciFinder®, Pubmed®, Google Scholar and Web of Science) on papers and patents and by systematic research in ethnopharmacological literature at various university libraries.

RESULTS

This review mainly introduced the current research on the anti-inflammatory active ingredient, anti-inflammatory effects of CMM, their mechanism, anti-inflammatory drug development of CMM, and toxicological information.

CONCLUSION

CMM is used clinically to treat inflammation symptoms in TCM, and its effect is mediated by multiple targets through multiple active ingredients. Although scholars around the world have made studies on the anti-inflammatory studies of CMM from different pathways and aspects and have made substantial progress, further studies are warranted to delineate the inflammation actions in more cogency models, establish the toxicological profiles and quality standards, assess the potentials of CMM in clinical applications, and make more convenient preparations easy to administrate for patients. Development of the clinically anti-inflammatory drugs are also warranted.

The therapeutic effects of daphnetin in collagen-induced arthritis involve its regulation of Th17 cells

OBJECTIVES

Daphne odora var. marginata (D. marginata), an aiophyllus arbuscular plant, is one of the traditional Chinese medicines used to treat rheumatoid arthritis. This study investigated the therapeutic effects and mechanisms of daphnetin, an active monomer ingredient derived from D. marginata, on collagen-induced arthritis (CIA) in rats.

METHODS

The effects of daphnetin on joint diseases were assessed by hematoxylin and eosin staining and radiographic and transmission electron microscopy. The protein and mRNA expression levels of T helper (Th)1/Th2/Th17-type cytokines in the spleen were determined by flow cytometry and quantitative real-time PCR.

RESULTS

Our results showed that daphnetin significantly reduced paw swelling and was nontoxic in vivo at the tested doses. Synovial hyperplasia, joint destruction and chondrocyte degeneration in CIA rats were suppressed by daphnetin. Daphnetin treatment also reduced the levels of Th1/Th2/Th17 type cytokines in spleen lymphocytes in CIA rats. Moreover, the expression of Foxp3, which can down-regulate the activity of Th17 cells, was significantly increased in the daphnetin-treated groups.

CONCLUSIONS

These results suggest that daphnetin may have therapeutic effects in down-regulating Th17-type responses in CIA rats. The beneficial effects of daphnetin on CIA may be related to its inhibition of Th17 cell priming and activation.