Daphnetin reduces endotoxin lethality in mice and decreases LPS-induced inflammation in Raw264.7 cells via suppressing JAK/STATs activation and ROS production

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.

High fat diet increases the severity of collagen-induced arthritis in mice by altering the gut microbial community

OBJECTIVES

Research has demonstrated that obesity may be associated with rheumatoid arthritis (RA). In addition, gut microbiota and its metabolites contribute to the occurrence and development of RA and obesity. However, the mechanism by which obesity affects RA remains unclear. In this study, we aimed to investigate whether gut microbiota and their metabolites alter the effects of high fat diet (HFD) on the severity of collagen-induced arthritis (CIA) in mice.

METHODS

Briefly, mice were divided into normal group (N), CIA model group (C), HFD group (T), and HFD CIA group (CT). Hematoxylin and Eosin staining(HE) and Safranin O-fast green staining were conducted, and levels of blood lipid and inflammatory cytokines were measured. 16S rDNA sequencing technique and liquid chromatography-mass spectrometry (LC-MS)-based metabolomics were performed to explore changes in the microbiota structure to further reveal the pathomechanism of HFD on CIA.

RESULTS

HFD aggravated the severity of CIA in mice. The CT group had the highest proportion of microbial abundance of Blautia, Oscillibacter, Ruminiclostridium-9, and Lachnospiraceae UCG 006 at the genus level, but had a lower proportion of Alistipes. Additionally, the fecal metabolic phenotype of the combined CT group shows significant changes, with differential metabolites enriched in 9 metabolic pathways, including primary bile acid biosynthesis, arginine biosynthesis, sphingolipid metabolism, purine metabolism, linoleic acid metabolism, oxytocin signaling pathway, aminoacyl-tRNA biosynthesis, the pentose phosphate pathway, and sphingolipid signaling pathway. Correlation analysis revealed that some of the altered gut microbiota genera were strongly correlated with changes in fecal metabolites, total cholesterol (TC), triglyceride (TG), and inflammatory cytokine levels.

CONCLUSIONS

This study shows that HFD may aggravate inflammatory reaction in CIA mice by altering the gut microbiota and metabolic pathways.

Hexahydrocurcumin from Zingiberis rhizoma attenuates lipopolysaccharide-induced acute pneumonia through JAK1/STAT3 signaling pathway

BACKGROUND

Pneumonia is one of the major causes of death after pathogens infection. Zingiberis rhizoma (GAN JIANG) is a herb that used in combination with other Chinese medicines to treat pathogen such as virus induced pneumonia. However, the affect of hexahydrocurcumin (HHC), a component from Zingiberis rhizoma, on pneumonia remains unknown.

PURPOSE

This study aims to explore the effects of HHC on lipopolysaccharide (LPS)-induced acute pneumonia, and to clarify the underlying mechanism.

METHODS

The pneumonia model of C57BL/6 mice was established by intratracheal injection of LPS to evaluate the therapeutic effect of HHC on lung injury and inflammation in vivo. RAW264.7 macrophages were utilized to illustrate the cellular mechanism of HHC in vitro.

RESULTS

HHC alleviated lung injury, ROS and inflammatory cytokine IL-6 production in pneumonia mice in vivo. Molecular docking results disclosed the binding of HHC to JAK1 protein. The study further showed that HHC suppressed the inflammatory cytokines such as IL-6, TNF-α, IL-1β gene expression, inhibited the phosphorylation of JAK1 but not JAK3, and the subsequent STAT3 phosphorylation in LPS-activated macrophages. HHC exhibited no effects on the protein levels of JAK1 and STAT3 in vitro. Consistently, HHC also attenuated the JAK1, STAT3 phosphorylation in pneumonia mice in vivo.

CONCLUSION

The results reveal that HHC attenuates pneumonia by targeted inhibition of JAK1/STAT3 signaling pathway. It indicates the novel role of HHC to treat pneumonia, and its potential applications for JAK inhibitor-treated diseases.

Daphnetin Alleviates Bleomycin-Induced Pulmonary Fibrosis through Inhibition of Epithelial-to-Mesenchymal Transition and IL-17A

Idiopathic pulmonary fibrosis (IPF) is a chronic and refractory interstitial lung disease. Although there is no cure for IPF, the development of drugs with improved efficacy in the treatment of IPF is required. Daphnetin, a natural coumarin derivative, has immunosuppressive, anti-inflammatory, and antioxidant activities. However, its antifibrotic effects have not yet been elucidated. In this study, we investigated the antifibrotic effects of daphnetin on pulmonary fibrosis and the associated molecular mechanism. We examined the effects of daphnetin on splenocytes cultured in Th17 conditions, lung epithelial cells, and a mouse model of bleomycin (BLM)-induced pulmonary fibrosis. We identified that daphnetin inhibited IL-17A production in developing Th17 cells. We also found that daphnetin suppressed epithelial-to-mesenchymal transition (EMT) in TGF-β-treated BEAS2B cells through the regulation of AKT phosphorylation. In BLM-treated mice, the oral administration of daphnetin attenuated lung histopathology and improved lung mechanical functions. Our findings clearly demonstrated that daphnetin inhibited IL-17A and EMT both in vitro and in vivo, thereby protecting against BLM-induced pulmonary fibrosis. Taken together, these results suggest that daphnetin has potent therapeutic effects on lung fibrosis by modulating both Th17 differentiation and the TGF-β signaling pathway, and we thus expect daphnetin to be a drug candidate for the treatment of IPF.

Maresin1 prevents sepsis-induced acute liver injury by suppressing NF-κB/Stat3/MAPK pathways, mitigating inflammation

Aims

The treatment of sepsis remains challenging and the liver is a non-neglectful target of sepsis-induced injury. Uncontrolled inflammatory responses exert a central role in the pathophysiological process of sepsis-induced acute liver injury (SI-ALI). Maresin1 (MaR1) is a derivative of omega-3 docosahexaenoic acid (DHA), which has been shown to have anti-inflammatory effects and is effective in a variety of sepsis-related diseases. This study aimed to determine the effect of MaR1 on cecal ligation and puncture (CLP)-caused SI-ALI and explore its possible mechanisms.

Main methods

Mice were subjected to CLP, and then intravenously injected via tail vein with low-dose MaR1 (0.5 ng, 200 μL) or high-dose MaR1 (1 ng, 200 μL) or sterile normal saline (NS) (200 μL) 1 h later. Then, the survival rate, body weight change, liver function, bacterial load, neutrophil infiltration, and inflammatory cytokines were detected.

Results

MaR1 significantly increased the 7-day survival rate and reduced the bacterial load in peritoneal lavage fluid and blood in a dose-dependent manner in mice with SI-ALI. Treatment with MaR1 could also restore the function of the liver in septic mice. Besides, MaR1 exerted anti-inflammatory effects by decreasing the expression of pro-inflammatory molecules (TNF-α, IL-6 and IL-1β), bacterial load, and neutrophil infiltration and increasing the expression of anti-inflammatory molecules (IL-10).

Significance

Our experimental results showed that MaR1 alleviated liver injury induced by sepsis. This work highlighted a potential clinic use of MaR1 in treating acute inflammation of SI-ALI, but also provided new insight into the underlying molecular mechanism.

Identification of a Hydroxygallic Acid Derivative, Zingibroside R1 and a Sterol Lipid as Potential Active Ingredients of Cuscuta chinensis Extract That Has Neuroprotective and Antioxidant Effects in Aged Caenorhabditis elegans

We examined the effects of the extracts from two traditional Chinese medicine plants, Cuscuta chinensis and Eucommia ulmoides, on the healthspan of the model organism Caenorhabditis elegans. C. chinensis increased the short-term memory and the mechanosensory response of aged C. elegans. Furthermore, both extracts improved the resistance towards oxidative stress, and decreased the intracellular level of reactive oxygen species. Chemical analyses of the extracts revealed the presence of several bioactive compounds such as chlorogenic acid, cinnamic acid, and quercetin. A fraction from the C. chinensis extract enriched in zingibroside R1 improved the lifespan, the survival after heat stress, and the locomotion in a manner similar to the full C. chinensis extract. Thus, zingibroside R1 could be (partly) responsible for the observed health benefits of C. chinensis. Furthermore, a hydroxygallic acid derivative and the sterol lipid 4-alpha-formyl-stigmasta-7,24(241)-dien-3-beta-ol are abundantly present in the C. chinensis extract and its most bioactive fraction, but hardly in E. ulmoides, making them good candidates to explain the overall healthspan benefits of C. chinensis compared to the specific positive effects on stress resistance by E. ulmoides. Our findings highlight the overall anti-aging effects of C. chinensis in C. elegans and provide first hints about the components responsible for these effects.

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 Mitigates Ovalbumin-Induced Allergic Rhinitis in Mice by Regulating Nrf2/HO-1 and TLR4/NF-kB Signaling

BACKGROUND

Allergic rhinitis (AR) is an inflammatory disorder of nasal mucosa resulting from allergen exposure. Daphnetin (DAP) is a coumarin derivative that has various bioactivities. Nevertheless, its specific function in AR is unclear.

OBJECTIVES

This study is aimed to explore the specific function of DAP in AR.

METHODS

An AR murine model was established by ovalbumin (OVA) induction. Murine sneezing and rubbing behaviors were observed. Hematoxylin-eosin was used for histopathological observation of nasal mucosa. ELISA was utilized for detection of cytokine production in murine serum. Oxidative stress-associated markers were assessed by commercial assay kits. Western blotting was utilized for evaluating protein levels of Toll-like receptor 4 (TLR4) and nuclear factor kappa B (NF-κB) in nasal mucosa.

RESULTS

DAP alleviated OVA-induced nasal symptoms, inflammatory response and oxidative stress in the AR murine model. DAP activated nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) signaling and inactivated TLR4/NF-κB signaling in murine nasal mucosa.

CONCLUSION

DAP mitigates OVA-induced AR in mice by activating Nrf2/HO-1 signaling and inactivating TLR4/NF-κB signaling.

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.

Carpelipines C and D, Two Anti-Inflammatory Germacranolides from the Flowers of Carpesium lipskyi Winkl. (Asteraceae)

Two new germacranolides, carpelipine C (1) and carpelipine D (2), together with four known ones (3-6), were isolated from Carpesium lipskyi Winkl. flowers, a folk Tibetan herbal medicine with antipyretic-analgesic and anti-inflammatory effects. The chemical structures of new structure were illuminated by diversified spectroscopic and X-ray crystallographic analyses. Compounds 1 and 3 dramatically suppressed the synthesis of NO and decreased pre-inflammatory protein expression of iNOS and COX-2 in LPS-induced RAW264.7 cells. Furthermore, it was revealed that NF-κB/MAPK signaling pathway were involved in the anti-inflammatory process of 1 and 3, and their effects on reducing oxidative stress by activating Nrf2/HO-1 pathway were also measured. This article indicated that the traditional use of C. lipskyi to treat inflammatory diseases has a certain rationality.

Up-regulation of Nrf2/HO-1 and inhibition of TGF-β1/Smad2/3 signaling axis by daphnetin alleviates transverse aortic constriction-induced cardiac remodeling in mice

Oxidative damage and accumulation of extracellular matrix (ECM) components play a crucial role in the adverse outcome of cardiac hypertrophy. Evidence suggests that nuclear factor erythroid-derived factor 2 related factor 2 (Nrf2) can modulate oxidative damage and adverse myocardial remodeling. Daphnetin (Daph) is a coumarin obtained from the plant genus Daphne species that exerts anti-oxidative and anti-inflammatory properties. Herein, we investigated the roles of Daph in transverse aortic constriction (TAC)-induced cardiac hypertrophy and fibrosis in mice. TAC-induced alterations in cardiac hypertrophy markers, histopathological changes, and cardiac function were markedly ameliorated by oral administration of Daph in mice. We found that Daph significantly reduced the reactive oxygen species (ROS) generation, increased the nuclear translocation of Nrf2, and consequently, reinstated the protein levels of NAD(P)H quinone dehydrogenase1 (NQO1), heme oxygenase-1 (HO-1), and other antioxidants in the heart. Besides, Daph significantly inhibited the TAC-induced accumulation of ECM components, including α-smooth muscle actin (α-SMA), collagen I, collagen III, and fibronectin, and interfered with the TGF-β1/Smad2/3 signaling axis. Further studies revealed that TAC-induced terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positive nuclei and the protein levels of Bax/Bcl2 ratio and cleaved caspase 3 were substantially decreased by Daph treatment. We further characterized the effect of Daph on angiotensin II (Ang-II)-stimulated H9c2 cardiomyoblast cells and observed that Daph markedly decreased the Ang-II induced increase in cell size, production of ROS, and proteins associated with apoptosis and fibrosis. Mechanistically, Daph alone treatment enhanced the protein levels of Nrf2, NQO1, and HO-1 in H9c2 cells. The inhibition of this axis by Si-Nrf2 transfection abolished the protective effect of Daph in H9c2 cells. Taken together, Daph effectively counteracted the TAC-induced cardiac hypertrophy and fibrosis by improving the Nrf2/HO-1 axis and inhibiting the TGF-β1/Smad2/3 signaling axis.

Daphnetin ameliorates Aβ pathogenesis via STAT3/GFAP signaling in an APP/PS1 double-transgenic mouse model of Alzheimer's disease

Alzheimer's disease (AD) has become a major public health problem that affects the elderly population. Therapeutic compounds with curative effects are not available due to the complex pathogenesis of AD. Daphnetin, a natural coumarin derivative and inhibitor of various kinases, has anti-inflammatory and antioxidant activities. In this study, we found that daphnetin improved spatial learning and memory in an amyloid precursor protein (APP)/presenilin 1 (PS1) double-transgenic mouse model of AD. Daphnetin markedly decreased the levels of amyloid-β peptide 1-40 (Aβ₄₀) and 1-42 (Aβ₄₂) in the cerebral cortex, downregulated the expressions of enzymes involved in APP processing, e.g., beta-site APP-cleaving enzyme (BACE), nicastrin and presenilin enhancer protein 2 (PEN2). We further found the reduced serum levels of inflammatory factors, including interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and chemokine (C-C motif) ligand 3 (CCL3), while daphnetin increased total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) levels in the serum. Interestingly, daphnetin markedly decreased the expression of glial fibrillary acidic protein (GFAP) and the upstream regulatory molecule- phosphorylated signal transducer and activator of transcription 3 (p-STAT3) in APP/PS1 mice, and mainly inhibited the phosphorylation of STAT3 at Ser727 to decrease GFAP expression evidenced in a LPS-activated glial cell model. These results suggest that daphnetin ameliorates cognitive deficits and that Aβ deposition in APP/PS1 mice is mainly correlated with astrocyte activation and APP processing.

Daphnetin ameliorates acute lung injury in mice with severe acute pancreatitis by inhibiting the JAK2-STAT3 pathway

Severe acute pancreatitis (SAP) is often associated with pulmonary inflammation leading to acute lung injury. Daphnetin, a natural coumarin derivative, has been reported to exert anti-inflammatory effects. Here, we explored the effect and possible mechanism of daphnetin in a mouse model of SAP-associated lung injury induced by an intraperitoneal injection of L-arginine. The severity of pancreatic and lung injury is determined by histology and its score. Immunostaining of inflammatory and apoptotic cells was used to demonstrate lung tissue inflammation and apoptosis; ELISA analysis of serum and tissue cytokine levels; and western blotting and immunohistochemical staining for the activated Janus kinase 2 (JAK2)-signal transducer and activator of transcription protein 3 (STAT3) signalling pathway in lung tissues. Daphnetin pretreatment significantly reduced SAP-induced pancreatic and lung tissue damage, reduced interleukin-6 and tumour necrosis factor-α concentrations in both serum and lung tissues, reduced serum amylase and myeloperoxidase activities, and reduced macrophage (CD11b) and neutrophil (Ly6G) infiltration and cell apoptosis in the lung tissue. Moreover, SAP-induced phosphorylation of JAK2 and STAT3 in the lung tissue was also significantly diminished by the daphnetin pretreatment. These results indicated that daphnetin reduces SAP-associated lung tissue damage, likely by inhibiting the activation of JAK2-STAT3 signalling.

Mechanistic interplay of various mediators involved in mediating the neuroprotective effect of daphnetin

Daphnetin is a 7, 8 dihydroxy coumarin isolated from different medicinal plants of the Thymelaeaceae family and exhibits copious pharmacological activities including neuroprotection, anti-cancer, anti-malarial, anti-inflammatory, anti-parasitic and anti-arthritic activity. It has been proved to be an effective neuroprotective agent in several preclinical animal studies and cell line examinations. It is found to interact with different cellular mediators and signaling pathways to confer protection against neurodegeneration. The reactive oxygen species and inflammatory mediators are the major culprits of different neurodegenerative diseases. Oxidative stress activates the pro-apoptotic proteins and inhibits anti-apoptotic proteins, leading to neuronal cell death. Daphnetin restores cellular redox balance by upregulating the antioxidants level (GSH and SOD), anti-apoptotic protein (Bcl-2), as well as by reducing the levels of proinflammatory cytokines, executioner caspase-3, pro-apoptotic-Bax, and oxidative stress markers. Furthermore, activation of Nrf-2/HO-1 signaling and upregulation of HSP-70 governs the protection elicited by daphnetin against oxidative stress-induced neuronal apoptosis. Daphnetin modulated inhibition of JNK-MAPK, JAK-STAT, and TLR-4/NF-κB signaling pathways also contributed to its neuroprotective effect. The positive effects of daphnetin have been also related to its AChE, BChE, and BACE-1 inhibitory potential. The present review has been designed to explore the mechanistic interplay of various mediators in mediating the neuroprotective effects of daphnetin.

Antifungal and Antiaging Evaluation of Aerial Part Extracts of Thymelaea hirsuta (L.) Endl

In western Algeria, Thymelaea hirsuta aerial parts are traditionally used topically for the treatment of human skin infections. For a better knowledge of its biological activities, this study aimed at evaluating the in vitro antifungal activity and antiaging properties of several extracts of the aerial parts by in vitro assays. Antifungal activity was investigated by using the reference microbroth dilution method (National Committee for Clinical Laboratory Standards) against the dermatophytes ( Microsporum audouinii, Nannizzia gypsea, Trichophyton interdigitale, and Trichophyton rubrum) and the yeast ( Candida albicans). Antiaging (inhibition of 1,1-diphenyl-2-picrylhyorazyl radical scavenging and tyrosinase, lipoxygenase, elastase, and hyaluronidase activities) assays were performed in 96-well plates. All the extracts of T. hirsuta exhibited antifungal activity against M. audouinii, T. rubrum, and C. albicans, while no activity was found against N. gypsea and T. interdigitale. The highest activity was observed on M. audouinii for the aqueous leaf (minimum inhibitory concentration [MIC] of 8 µg/mL) and stem extracts (MIC = 31 µg/mL) and the methanolic leaf extract (MIC = 8 µg/mL). Additionally, some marked morphological alterations were observed on M. audouinii hyphae with all aqueous extracts. Concerning antiage bioassays, the major activity was found against hyaluronidase for the aqueous and methanolic extracts from leaves and the methanolic extract from flowers. Analysis of this last extract by high-performance liquid chromatography, electrospray ionization-mass spectrometry, and nuclear magnetic resonance, allowed us to identify daphnoretin and daphnetin as major components of this extract, and, therefore, responsible for the antiaging activity. In conclusion, this study provides additional experimental data supporting the traditional use of T. hirsuta extracts on some cutaneous dermatophytosis, as well as new perspectives on the potential use of T. hirsuta to ensure better healing of the skin.

Phytochemicals: Potential Therapeutic Interventions Against Coronavirus-Associated Lung Injury

Since the outbreak of coronavirus disease 2019 (COVID-19) in December 2019, millions of people have been infected and died worldwide. However, no drug has been approved for the treatment of this disease and its complications, which urges the need for finding novel therapeutic agents to combat. Among the complications due to COVID-19, lung injury has attained special attention. Besides, phytochemicals have shown prominent anti-inflammatory effects and thus possess significant effects in reducing lung injury caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Also, the prevailing evidence reveales the antiviral effects of those phytochemicals, including anti-SARS-CoV activity, which could pave the road in providing suitable lead compounds in the treatment of COVID-19. In the present study, candidate phytochemicals and related mechanisms of action have been shown in the treatment/protection of lung injuries induced by various methods. In terms of pharmacological mechanism, phytochemicals have shown potential inhibitory effects on inflammatory and oxidative pathways/mediators, involved in the pathogenesis of lung injury during COVID-19 infection. Also, a brief overview of phytochemicals with anti-SARS-CoV-2 compounds has been presented.

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.

Coumarins as Modulators of the Keap1/Nrf2/ARE Signaling Pathway

The Keap1/Nrf2/ARE system is a central defensive mechanism against oxidative stress which plays a key role in the pathogenesis and progression of many diseases. Nrf2 is a redox-sensitive transcription factor controlling a variety of downstream antioxidant and cytodefensive genes. Nrf2 has a powerful anti-inflammatory activity mediated via modulating NF-κB. Therefore, pharmacological activation of Nrf2 is a promising therapeutic strategy for the treatment/prevention of several diseases that are underlined by both oxidative stress and inflammation. Coumarins are natural products with promising pharmacological activities, including antioxidant, anticancer, antimicrobial, and anti-inflammatory efficacies. Coumarins are found in many plants, fungi, and bacteria and have been widely used as complementary and alternative medicines. Some coumarins have shown an ability to activate Nrf2 signaling in different cells and animal models. The present review compiles the research findings of seventeen coumarin derivatives of plant origin (imperatorin, visnagin, urolithin B, urolithin A, scopoletin, esculin, esculetin, umbelliferone, fraxetin, fraxin, daphnetin, anomalin, wedelolactone, glycycoumarin, osthole, hydrangenol, and isoimperatorin) as antioxidant and anti-inflammatory agents, emphasizing the role of Nrf2 activation in their pharmacological activities. Additionally, molecular docking simulations were utilized to investigate the potential binding mode of these coumarins with Keap1 as a strategy to disrupt Keap1/Nrf2 protein-protein interaction and activate Nrf2 signaling.

A Tropical Lichen, Dirinaria consimilis Selectively Induces Apoptosis in MCF-7 Cells through the Regulation of p53 and Caspase-Cascade Pathway

BACKGROUND

Breast cancer is the most leading cause of death, with 49.9% of crude incidence rate and 12.9% of crude mortality rate. Natural resources have been extensively used throughout history for better and safer treatment against various diseases.

OBJECTIVES

The present study was aimed to investigate the antioxidant and anticancer potential of a tropical lichen Dirinaria consimilis (DCME) and its phytochemical analysis.

METHODS

The DCME was preliminarily evaluated for ROS, and RNS scavenging potential. Furthermore, DCME was evaluated for in vitro anticancer activity through cell proliferation assay, cell cycle analysis, annexin V/PI staining, morphological analysis, and western blotting study. Finally, the HPLC and LC-MS analyses were done to identify probable bioactive compounds.

RESULTS

The in vitro antioxidant studies showed promising ROS, and RNS scavenging potential of DCME. Moreover, the in vitro antiproliferative study bared the cytotoxic nature of DCME towards MCF-7 (IC50 - 98.58 ± 6.82μg/mL) and non-toxic towards WI-38 (IC50 - 685.85 ± 19.51μg/mL). Furthermore, the flow-cytometric analysis revealed the increase in sub G1 population as well as early apoptotic populations dose-dependently. The results from confocal microscopy showed the DNA fragmentation in MCF-7 upon DCME treatment. Finally, the western blotting study revealed the induction of tumor suppressor protein, p53, which results in increasing the Bax/Bcl-2 ratio and activation of caspase-cascade pathways.

CONCLUSION

The activation of caspase-3, -8, -9 and PARP degradation led us to conclude that DCME induces apoptosis in MCF-7 through both intrinsic and extrinsic mechanisms. The LC-MS analysis showed the presence of various bioactive compounds.

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.

Crocin has pharmacological effects against the pathological behavior of colon cancer cells by interacting with the STAT3 signaling pathway

The aim of the present study was to investigate changes in proliferation, apoptosis, inflammation and chemokine release of colon cancer cells after treatment with crocin, as well as to investigate the signaling pathway that is regulated by crocin. The inhibition rates of different doses of crocin on the proliferation of HCT116 cells were measured by MTT assay. The IC₅₀ was calculated from the inhibition rates at 48 h. Proliferation curves of HCT116 cells were plotted after treatment with 271.18 µM (high-dose group) or 135.6 µM (low-dose group) crocin. Flow cytometry and Hoechst 33342/propidium iodide double staining were used for detecting apoptosis. ELISA was used to measure the levels of macrophage inflammatory protein 2, interleukin (IL)-8, monocyte chemoattractant protein 1, tumor necrosis factor-α, IL-6 and IL-1β in the supernatant from cultured HCT116 cells following both high- and low-dose crocin treatment. Phosphorylated (P)-STAT3/STAT3 in HCT116 cells were measured by western blotting. Crocin inhibited the proliferation of HCT116 cells in a dose-dependent manner and the high-dose treatment with crocin resulted in a lower rate of proliferation. Additionally, crocin increased the apoptosis of HCT116 cells and the high-dose treatment with crocin led to a higher level of apoptosis. Notably, crocin decreased the secretion of chemokines and inflammatory factors from HCT116 cells and the high-dose treatment with crocin caused the greatest reduction in secretion of the factors. Crocin reduced the ratio of P-STAT3/STAT3, and thereby reduced the release of cytokines. The present study demonstrated that crocin may have pharmacological effects against the pathological behavior of colon cancer cells, and its mechanism of action may be related to the STAT3 signaling pathway.

7,8-dimethoxycoumarin Attenuates the Expression of IL-6, IL-8, and CCL2/MCP-1 in TNF-α-Treated HaCaT Cells by Potentially Targeting the NF-κB and MAPK Pathways

7,8-dimethoxycoumarin (DMC, C11H10O4), a natural coumarin compound, is present in Citrus plants including Citrus decumana and grapefruit. It is known to have protective effects on the kidneys against Cisplatin and ischemia-reperfusion injury. However, the underlying mechanisms of its inhibitory effects on skin inflammation have not been investigated in vitro. Tumor necrosis factor (TNF)-α is known to be one of the main causative agents of skin inflammation. It induces pro-inflammatory cytokines and chemokines by activating nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling. In this study, we investigated the inhibitory effect of DMC on the expression of pro-inflammatory cytokines and chemokines in TNF-α-treated human keratinocyte HaCaT cells. Pretreatment with DMC inhibited TNF-α-treated cytokines (interleukin 6; IL-6) and chemokines (IL-8 and monocyte chemoattractant protein-1). In addition, DMC significantly inhibited TNF-α-treated NF-κB activation and phosphorylation of MAPKs, such as c-Jun N-terminal kinases (JNK) and extracellular-signal-regulated kinase (ERK). These results suggest that DMC may elicit an anti-inflammatory response by suppressing TNF-α-treated activation of NF-κB and MAPK pathways in keratinocytes. Hence, it might be a useful therapeutic drug against skin inflammatory diseases.

Effects of daphnetin on lipid metabolism, insulin resistance and oxidative stress in OA‑treated HepG2 cells

Non‑alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease, and has high rates of morbidity and mortality worldwide. Daphnetin (DAP) possesses notable antioxidative, anti‑inflammatory and anticoagulant activities; DAP is an active ingredient extracted from Daphne Koreana Nakai. To investigate the effects and the underlying mechanism of DAP on NAFLD, we treated HepG2 cells with oleic acid (OA) and DAP simultaneously and non‑simultaneously. In the simultaneous treatment condition, HepG2 cells were co‑treated with 0.5 mM OA and DAP (5, 20, and 50 µM) for 24 h. In the non‑simultaneous treatment conditions, HepG2 cells were pretreated with 0.5 mM OA for 24 h, and then treated with DAP (5, 20 and 50 µM) for 24 h. Following the aforementioned treatments, the biochemical indexes associated with NAFLD were measured as follows: i) The intracellular contents of triglyceride (TG), reactive oxygen species (ROS) and fluorescent glucose 2‑[N‑(7‑nitrobenz‑2‑oxa‑1,3‑diazol‑4‑yl) amino]‑2‑deoxyglucose were analyzed with corresponding detection kits; and ii) the cellular expression levels of glycolipid metabolism‑ and oxidative stress‑related genes, including 5'AMP‑activated protein kinase (AMPK), sterol regulatory element‑binding protein‑1C (SREBP‑1C), patatin‑like phospholipase domain‑containing protein 3 (PNPLA3), peroxisome proliferator‑activated receptor α (PPARα), phosphoinositide 3‑kinase (PI3K), protein kinase B (AKT), nuclear factor‑like 2 (Nrf2), cytochrome P450 (CYP) 2E1 and CYP4A were determined by reverse transcription‑quantitative polymerase chain reaction and western blotting. The results revealed the potential mechanism underlying the effects of DAP on NAFLD in vitro: i) By increasing the phosphorylation of AMPK, DAP inhibited the expression of SREBP‑1C and PNPLA3, and induced that of PPARα. Lipid accumulation within hepatocytes was reduced; ii) by upregulating PI3K expression and pAKT/AKT levels, DAP may alleviate insulin resistance and promote hepatocellular glucose uptake; and iii) by upregulating the expression of Nrf2, DAP downregulated the expression of CYP2E1 and CYP4A, and the levels of reactive oxygen species in hepatocytes.

Treatment with 3,4-dihydroxyphenylethyl alcohol glycoside ameliorates sepsis-induced ALI in mice by reducing inflammation and regulating M1 polarization

The bioactive phenylethanoid 3,4-dihydroxyphenylethyl alcohol glycoside (DAG) is a component isolated from Sargentodoxa cuneata. The effects of DAG on acute lung injury (ALI) are largely unknown. Here, the effects of DAG on sepsis-induced ALI were investigated, and the related mechanisms were explored. Male C57BL/6 mice were used to establish a sepsis-induced ALI model. Levels of inflammatory cytokines were determined using real-time quantitative reverse transcription PCRs (qRT-PCR) and enzyme-linked immunosorbent assays (ELISAs). Pathological changes in the lung tissues were evaluated using haematoxylin and eosin (HE) staining. Mouse survival was quantified, and macrophage polarization was analyzed using flow cytometry. Our results showed that, in septic mice, pretreatment with DAG significantly improved survival, reduced histological damage in the lung, and suppressed the inflammatory response by inhibiting the activation of the NF-κB, STAT3, and p38 MAPK signaling pathways. Moreover, DAG treatment reduced the percentage of M1 macrophages in the bronchoalveolar lavage fluid (BALF) and spleen. In addition, DAG treatment decreased the production of pro-inflammatory cytokines and suppressed the activation of the NF-κB, STAT3, and p38 MAPK signaling pathways in LPS-induced MH-S cells. DAG treatment also reduced the relative abundances of M1 macrophages and M1 macrophage markers by suppressing the activation of the Notch1 signaling pathway. Thus, our results provided new insights for the development of drugs to treat ALI.

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: A Novel Anti-Helicobacter pylori Agent

Background: Antibiotic-resistant H. pylori was increasingly found in infected individuals, which resulted in treatment failure and required alternative therapeutic strategies. Daphnetin, a coumarin-derivative compound, has multiple pharmacological activities. Methods: The mechanism of daphnetin on H. pylori was investigated focusing on its effect on cell morphologies, transcription of genes related to virulence, adhesion, and cytotoxicity to human gastric epithelial (GES-1) cell line. Results: Daphnetin showed good activities against multidrug resistant (MDR) H. pylori clinical isolates, with minimal inhibitory concentration (MIC) values ranging from 25 to 100 μg/mL. In addition, daphnetin exposure resulted in H. pylori morphological changes. Moreover, daphnetin caused increased translocation of phosphatidylserine (PS), DNA damage, and recA expression, and RecA protein production vs. control group. Of great importance, daphnetin significantly decreased H. pylori adhesion to GES-1 cell line vs. control group, which may be related to the reduced expression of colonization related genes (e.g., babA and ureI). Conclusions: These results suggested that daphnetin has good activity against MDR H. pylori. The mechanism(s) of daphnetin against H. pylori were related to change of membrane structure, increase of DNA damage and PS translocation, and decrease of H. pylori attachment to GES-1 cells.

Daphnetin inhibits RANKL-induced osteoclastogenesis in vitro

Osteoporosis is a common orthopedic disease which is associated with hyper-activated osteoclastogenesis. Daphnetin is a natural coumarin derivative isolated from Genus Daphne, which possesses antiarthritis effect. However, the role of daphnetin in osteoclastogenesis has not been illustrated. This study aimed to investigate the effects of daphnetin on receptor activator of NF-κB ligand (RANKL)-induced osteoclastogenesis in vitro. Our results showed that the osteoclast formation was significantly suppressed by daphnetin treatment in bone marrow-derived macrophages (BMMs), which was illustrated by reduced number of tartrate-resistant acid phosphatase positive multinucleated osteoclasts and decreased expression levels of tumor necrosis factor receptor-associated factors (TRAF6), c-Fos, nuclear factor of activated T cells c1, and cathepsin K. RANKL caused significant induction effects in reactive oxygen species (ROS) generation and nicotinamide adenine dinucleotide phosphate oxidase activity, whereas the induction was dramatically reduced after pretreatment with daphnetin. In addition, daphnetin prevented the RANKL-induced activation of NF-κB and Akt/GSK-3β pathways in BMMs. These findings indicated that daphnetin exhibited an inhibitory effect on RANKL-induced osteoclastogenesis in vitro. The effect of daphnetin might be mediated by inhibiting ROS signal transduction, as well as preventing the activation of NF-κB and Akt/GSK-3β signaling pathways. These findings indicated that daphnetin might be considered as a new therapeutic approach for the osteoporosis treatment.

Clopidogrel reduces lipopolysaccharide-induced inflammation and neutrophil-platelet aggregates in an experimental endotoxemic model

Platelet activation contributes to organs failure in inflammation and plays an important role in endotoxemia. Clopidogrel inhibits platelet aggregation and activation. However, the role of clopidogrel in modulating inflammatory progression of endotoxemia remains largely unexplored. Therefore, we investigated the role of clopidogrel on the activation of platelet and leukocytes in lipopolysaccharide (LPS)-induced inflammation in mice. Animals were treated with clopidogrel or vehicle before LPS induction. The expression of neutrophil-platelet aggregates and platelet activation and tissue factor was determined. Immunofluorescence was used to analyze platelet-leukocyte interactions and tissue factor (TF) expression on leukocytes. Clopidogrel pretreatment markedly decreased lung damage, inhibited platelet-neutrophil aggregates and TF expression. In addition, clopidogrel reduced thrombocytopenia and affected the number of circulating white blood cell in endotoxemia mice. Moreover, clopidogrel also reduced platelet shedding of CD40L and CD62P in endotoxemic mice. Taken together, clopidogrel played an important role through reducing platelet activation and inflammatory process in endotoxemia.

Daphnetin protects hippocampal neurons from oxygen-glucose deprivation-induced injury

Daphnetin, a coumarin derivative extracted from Daphne odora var., was reported to possess a neuroprotective effect. Recently, it has been demonstrated that daphnetin attenuates ischemia/reperfusion (I/R) injury. However, the role of daphnetin in cerebral I/R injury and the potential mechanism have not been fully understood. The present study aimed to explore the regulatory roles of daphnetin on oxygen-glucose deprivation/reoxygenation (OGD/R)-induced cell injury in a model of hippocampal neurons. Our results demonstrated that daphnetin improved cell viability and reduced the lactate dehydrogenase leakage in OGD/R-stimulated hippocampal neurons. In addition, daphnetin inhibited oxidative stress and cell apoptosis in hippocampal neurons after OGD/R stimulation. Furthermore, daphnetin significantly enhanced the nuclear translocation of the nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) expression in hippocampal neurons exposed to OGD/R. Knockdown of Nrf2 blocked the protective effect of daphnetin on OGD/R-induced hippocampal neurons. In conclusion, these findings demonstrated that daphnetin attenuated oxidative stress and neuronal apoptosis after OGD/R injury through the activation of the Nrf2/HO-1 signaling pathway in hippocampal neurons. Thus, daphnetin may be a novel therapeutic agent for cerebral I/R injury.

Integrated Serum and Fecal Metabolomics Study of Collagen-Induced Arthritis Rats and the Therapeutic Effects of the Zushima Tablet

The Zushima tablet (ZT) has been used for decades in the clinical treatment of rheumatoid arthritis (RA) in China. However, its therapeutic mechanism is unclear. In this study, we aimed to explore the distinctive metabolic patterns in collagen-induced arthritis (CIA) rats and evaluate the therapeutic effects of ZT on RA using untargeted serum and fecal metabolomics approaches based on gas chromatography coupled with mass spectrometry. Body weight, hind paw swelling, TNF-α and IL-1β levels, arthritis scores, and histopathological parameters were assessed. In the metabolomics study, 31 altered metabolites in the serum and 30 in the feces were identified by comparing the model with the control group using statistical processing. These altered metabolites revealed that the tricarboxylic acid cycle, glycolysis metabolism, fatty acid metabolism, and purine metabolism were disturbed in CIA rats, and most of these altered metabolites including l-isoleucine, l-aspartic acid, pyruvic acid, cholic acid, and hypoxanthine, were rectified by ZT. Furthermore, short-chain fatty acids in feces were quantitatively determined, and the results showed that ZT could regulate the levels of propionate, butyrate, and valerate in CIA rats. Then, gut microbiota were analyzed by 16S rRNA analysis. Our results showed that Firmicutes and Bacteroidetes were the most abundant bacteria in rats. The levels of 19 types of bacteria at the family level were altered in RA rats, and most of them could be regulated by ZT. This study demonstrated that metabolomics analysis is a powerful tool for providing novel insight into RA and for elucidating the potential mechanism of ZT.