Comparative study of the antioxidant and anti-inflammatory effects of the natural coumarins 1,2-benzopyrone, umbelliferone and esculetin: in silico, in vitro and in vivo analyses.

The aim of this work was to compare the anti-inflammatory and antioxidant effects of three natural coumarins: 1,2-benzopyrone, umbelliferone and esculetin. The antioxidant capacity of coumarins was evaluated using both chemical and biological in vitro assays. Chemical assays included DPPH and ABTS∙+ radical scavenging as well as ferric ion reducing ability power (FRAP) assay. Inhibition of mitochondrial ROS generation and lipid peroxidation in brain homogenates were used as biological in vitro assays. The experimental method of carrageenan-induced pleurisy in rats was used for the in vivo investigation of the anti-inflammatory activity. In silico molecular docking analysis was undertaken to predict the affinity of COX-2 to the coumarins. Considering the antioxidant capacity, esculetin was the most efficient one as revealed by all employed assays. Particularly, the mitochondrial ROS generation was totally abolished by the compound at low concentrations (IC50 = 0.57 µM). As for the anti-inflammatory effects, the COX-2 enzyme presented good affinities to the three coumarins, as revealed by the molecular docking analyses. However, considering the in vivo anti-inflammatory effects, 1,2-benzopyrone was the most efficient one in counteracting pleural inflammation and it potentiated the anti-inflammatory actions of dexamethasone. Umbelliferone and esculetin treatments failed to reduce the volume of pleural exudate. Overall, therefore, our results support the notion that this class of plant secondary metabolites displays promising effects in the prevention and/or treatment of inflammation and other diseases associated with oxidative stress, although the singularities regarding the type of the inflammatory process and pharmacokinetics must be taken into account.

Pharmacological activities of esculin and esculetin: A review.

Esculin and esculetin are 2 widely studied coumarin components of Cortex Fraxini, which is a well-known herbal medicine with a 2000-year history. In vivo and in vitro studies have demonstrated that both have a variety of pharmacological activities, including antioxidant, anti-tumor, anti-inflammatory, antibacterial, antidiabetic, immunomodulatory, anti-atherosclerotic, and so on. Their underlying mechanisms of action and biological activities include scavenging free radicals, modulating the nuclear factor erythroid 2-related factor 2 pathway, regulating the cell cycle, inhibiting tumor cell proliferation and migration, promoting mitochondrial pathway apoptosis, inhibiting the NF-κB and MAPK signaling pathways, regulating CD4+ T cells differentiation and associated cytokine release, inhibiting vascular smooth muscle cells, etc. This review aims to provide comprehensive information on pharmacological studies of esculin and esculetin, which is of noteworthy importance in exploring the therapeutic potential of both coumarin compounds.

Daphnetin contributes to allergen-induced Th2 cytokine expression and type 2-immune responses in atopic dermatitis and asthma.

Daphne koreana Nakai is a cherished medicinal plant in the Changbai Mountain region of China. It can be incorporated into medicinal meals and used for various skin diseases by infiltrating liquor. Daphnetin (7,8-dihydroxycoumarin, Dap.) is a main constituent of D. koreana Nakai, which has been used to treat inflammatory conditions and immune disorders due to its numerous pharmacological activities, including anti-oxidant, anti-inflammatory, analgesic, etc. Atopic dermatitis (AD) and allergic asthma are typical diseases of type 2-immune responses. In the present study, the therapeutic potential of Dap. against AD and allergic asthma was investigated using animal and cell experiments. AD-like lesions were induced by repeated application of 1-chloro-2,4-dinitrobenzene (DNCB) to the shaved dorsal skin of BALB/c mice. Ovalbumin (OVA) induction was utilized to establish a mouse asthma model. A passive cutaneous anaphylaxis (PCA) mouse ear model and immunoglobulin E (IgE)/bovine serum albumin (BSA)-stimulated RBL-2H3 cells were used for in vitro assays. The skin lesions and serum and tissue homogenates of the mice were analyzed using histological analysis, immunohistochemistry (IHC) and enzyme-linked immunosorbent assay (ELISA), respectively, in order to investigate the anti-AD effects of Dap. Histological analysis was performed on the allergic asthma model to observe inflammatory cell infiltration in the lung tissues. Total IgE and OVA-specific IgE in the serum were measured by ELISA. The levels of inflammatory cytokines in BALF were detected by ELISA. In addition, ELISA and western blotting were performed for the in vitro analysis of RBL-2H3 cells. The results showed that Dap. inhibited the development of DNCB-induced AD-like lesions in the BALB/c mice by reducing the severity of the lesions, epidermal thickness and mast cell infiltration; this was accompanied by reduced levels of IgE and inflammatory cytokines [interleukin (IL)-4, IL-5, IL-9, IL-13, IL-33 and thymic stromal lymphopoietin (TSLP)]. In the allergic asthma model, Dap. reduced the number of infiltrated inflammatory cells in the lung tissues. Moreover, the levels of total serum IgE and OVA-specific IgE were reduced in the high daphnetin dose groups (Dap., -100 mg kg-1). Dap. administered at a dose of -100 mg kg-1 decreased the levels of inflammatory cytokines (IL-4, IL-5, IL-9, IL-13, IL-33 and TSLP in BALF). Furthermore, Dap. administered to IgE-sensitized mice effectively attenuated the IgE-triggered PCA reaction. In vitro, Dap. decreased the expression levels of histamine, IL-4, IL-6, IL-13, MIP-1α and INF-α, and reduced the protein expression levels of phosphorylated MAPKs, P-Lyn and P-syk in the RBL-2H3 cells. Therefore, Dap. can be represented as a potential therapeutic strategy for the treatment of allergic inflammatory conditions via immunoregulation.

Umbelliferone Inhibits Migration, Invasion and Inflammation of Rheumatoid Arthritis Fibroblast-Like Synoviocytes and Relieves Adjuvant-Induced Arthritis in Rats by Blockade of Wnt/ß-Catenin Signaling Pathway.

Umbelliferone (UMB), a natural coumarin compound, has been reported to possess anti-rheumatic effects on rheumatoid arthritis (RA) experimental models, but its potential role of UMB in regulating migration, invasion and inflammation of RA fibroblast-like synoviocytes (FLS) remain unclear. Herein, MTT assay was performed to confirm the non-cytotoxic concentrations (10, 20, and 40[Formula: see text][Formula: see text]M) and the treatment time (24[Formula: see text]h) of UMB on TNF-[Formula: see text]-stimulated RA FLS (MH7A cells) in vitro. Results of wound-healing, transwell and phalloidin staining assays revealed that UMB inhibited TNF-[Formula: see text]-induced migration, invasion and F-actin cytoskeletal reorganization in MH7A. Results of ELISA, western blot and gelatin zymography indicated that UMB decreased the productions of pro-inflammatory factors, including IL-1[Formula: see text], IL-6, IL-8, MMP-2 and MMP-9, and inhibited MMP-2 activity in TNF-[Formula: see text]-stimulated MH7A cells. In vivo, UMB (25[Formula: see text]mg/kg and 50[Formula: see text]mg/kg) relieved the joint damage and synovial inflammation in rats with adjuvant-induced arthritis (AIA). Mechanistically, UMB could suppress Wnt/[Formula: see text]-catenin signaling both in TNF-[Formula: see text]-induced MH7A cells and in AIA rat synovium, evidenced by decreasing Wnt1 protein level, activating GSK-3[Formula: see text] kinase by blocking GSK-3[Formula: see text] (Ser9) phosphorylation, and reducing the protein level and nuclear translocation of [Formula: see text]-catenin. Importantly, combined use of lithium chloride (a Wnt/[Formula: see text]-catenin signaling agonist) eliminated the inhibitory effects of UMB on migration, invasion and inflammation in vitro and the anti-arthritic effects of UMB in vivo. We concluded that UMB inhibited TNF-[Formula: see text]-induced migration, invasion and inflammation of RA FLS and attenuated the severity of rat AIA through its ability to block Wnt/[Formula: see text]-catenin signaling pathway.

Aesculetin exhibited anti-inflammatory activities through inhibiting NF-кB and MAPKs pathway in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: Aesculetin (6,7-dihydroxy-2H-1-benzopyran-2-one) has been reported to exhibit potent anti-inflammatory property both in vitro and in vivo. AIMS OF THIS STUDY: In this study, we evaluated the anti-inflammatory effect and investigated underlying molecular mechanisms of aesculetin in LPS-induced RAW264.7 macrophages and DSS-induced colitis. MATERIALS AND METHODS: In this study, the production of NO, TNF-α, and IL-6 were measured to identify the aesculetin with potent anti-inflammatory effect. Then, the underlying anti-inflammatory mechanisms were explored by western blotting in LPS-induced cells. Next, we verify the anti-inflammatory potential of aesculetin in DSS-induced colitis in vivo. The clinical symptoms of colitis, including weight loss, DAI, colon length and MPO activity, and the secretion of TNF-α and IL-6 were evaluated. Finally, Western blot analysis was applied to further investigate underlying mechanism in DSS-induced colitis model. RESULTS: Our studies showed that aesculetin exhibited anti-inflammatory potential by inhibiting NO, TNF-α, and IL-6 production and reducing iNOS and NLRP3 expression in LPS-induced RAW264.7 cells. Mechanically, we found that aesculetin significantly inhibited LPS-induced activation of NF-κB and MAPKs signaling pathways. In DSS-induced mouse model, the colitis-related symptoms were relieved by treatment with aesculetin. Besides, aesculetin also inhibited the secretion of TNF-α and IL-6, and the activation of NF-κB and MAPKs signaling pathways in DSS-induced colitis. CONCLUSIONS: The anti-inflammatory effect of aesculetin was connected with its inhibition on the activation of NF-κB and MAPKs signaling pathways both in vitro and in vivo. Therefore, aesculetin was expected to be developed as an anti-inflammatory drug.

Effects of Itxasol© Components on Gene Expression in Bacteria Related to Infections of the Urinary Tract and to the Inflammation Process.

Urinary tract infections (UTIs) represent a health problem of the first magnitude since they affect large segments of the population, cause increased mortality and comorbidity, and have a high incidence of relapse. Therefore, UTIs cause a major socioeconomic concern. Current antibiotic treatments have various limitations such as the appearance of resistance to antibiotics, nephrotoxicity, and side effects such as gastrointestinal problems including microbiota alterations that contribute to increasing antibiotic resistance. In this context, Itxasol© has emerged, approved as an adjuvant for the treatment of UTIs. Designed with biomimetic principles, it is composed of arbutin, umbelliferon, and N-acetyl cysteine. In this work, we review the activities of these three compounds concerning the changes they produce in the expression of bacterial genes and those related to inflammation as well as assess how they are capable of affecting the DNA of bacteria and fungi.

Umbelliferone Ameliorates Benign Prostatic Hyperplasia by Inhibiting Cell Proliferation and G1/S Phase Cell Cycle Progression through Regulation of STAT3/E2F1 Axis.

Umbelliferone (UMB), also known as 7-hydroxycoumarin, is a derivative of coumarin, which is widely found in many plants such as carrots, coriander, and garden angelica. Although many studies have already revealed the various pharmacological properties of UMB, its effect on benign prostatic hyperplasia (BPH) remains unclear. Therefore, the present study aimed to elucidate the underlying mechanism of the anti-proliferative effect of UMB in a human benign prostatic hyperplasia cell line (BPH-1), as well as its ameliorative effect on BPH in testosterone propionate (TP)-induced rats. The results showed that UMB exerts an anti-proliferative effect in BPH-1 cells by modulating the signal transducer and activator of transcription 3 (STAT3)/E2F transcription factor 1 (E2F1) axis. UMB treatment not only inhibited androgen/androgen receptor (AR) signaling-related markers, but also downregulated the overexpression of G1/S phase cell cycle-related markers. In TP-induced rats, UMB administration demonstrated an anti-BPH effect by significantly reducing prostate size, weight, and epithelial thickness. In addition, UMB suppressed cell proliferation by reducing the expression of proliferating cell nuclear antigen (PCNA) and p-STAT3 (Tyr 705) in prostate tissue following TP injection. These findings suggest that UMB has pharmacological effects against BPH.

A Natural Alternative Treatment for Urinary Tract Infections: Itxasol©, the Importance of the Formulation.

Genito-urinary tract infections have a high incidence in the general population, being more prevalent among women than men. These diseases are usually treated with antibiotics, but very frequently, they are recurrent and lead to the creation of resistance and are associated with increased morbidity and mortality. For this reason, it is necessary to develop new compounds for their treatment. In this work, our objective is to review the characteristics of the compounds of a new formulation called Itxasol© that is prescribed as an adjuvant for the treatment of UTIs and composed of ß-arbutin, umbelliferon and n-acetyl cysteine. This formulation, based on biomimetic principles, makes Itxasol© a broad-spectrum antibiotic with bactericidal, bacteriostatic and antifungal properties that is capable of destroying the biofilm and stopping its formation. It also acts as an anti-inflammatory agent, without the adverse effects associated with the recurrent use of antibiotics that leads to renal nephrotoxicity and other side effects. All these characteristics make Itxasol© an ideal candidate for the treatment of UTIs since it behaves like an antibiotic and with better characteristics than other adjuvants, such as D-mannose and cranberry extracts.

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.

Protective Effect of Esculetin, Natural Coumarin in Mice Model of Fibromyalgia: Targeting Pro-Inflammatory Cytokines and MAO-A.

Fibromyalgia is a refractory syndrome characterized by chronic wayward pain and complex co-morbid psychological trepidation. The current treatments have a limited role and proper clinical benefits are far from satisfactory. Naturally occurring coumarins such as osthole are known to have analgesic and anti-inflammatory activities. Therefore, the current investigation was designed to explore the potential of natural coumarin esculetin (2.5, 5, and 10 mg/kg) in mitigating reserpine-induced fibromyalgia in Swiss albino mice. Esculetin is a 6,7 dihydroxy-coumarin obtained from various plant sources such as Aesculus hippocastanum L, Ceratostigma willmottianum, Citrus limonia, etc. Reserpine (0.5 mg/kg/day s.c.) treatment for first 3 days, significantly altered the behavior of mice as evidenced by reduced paw withdrawal threshold in pressure application measurement (PAM) test and electronic von-Frey (eVF) test, increased immobility time in forced swim test (FST), increased latency to reach the platform in Morris water maze (MWM) test and reduced number of square crossed in the open field test (OFT). These behavioral deficits with reserpine treatment were integrated with a reduced level of serotonin (5-HT), reduced glutathione (GSH), along with an increase in monoamine oxidase-A (MAO-A) activity, pro-inflammatory cytokines (IL-1ß, TNF-α), thiobarbituric acid reactive substances (TBARS) and glutamate level. Esculetin (10 mg/kg/day i.p) treatment for 5 days, significantly abrogated reserpine induced behavioral and biochemical alterations. Whereas, no significant improvement was observed with lower doses of esculetin i.e. 2.5 and 5 mg/kg.

Xanthotoxin and umbelliferone attenuate cognitive dysfunction in a streptozotocin-induced rat model of sporadic Alzheimer's disease: The role of JAK2/STAT3 and Nrf2/HO-1 signalling pathway modulation.

The aim of the present study was to assess the neuroprotective effects of xanthotoxin and umbelliferone in streptozotocin (STZ)-induced cognitive dysfunction in rats. Animals were injected intracerebroventricularly (ICV) with STZ (3 mg/kg) once to induce a sporadic Alzheimer's disease (SAD)-like condition. Xanthotoxin or umbelliferone (15 mg/kg, i.p.) were administered 5 hr after ICV-STZ and daily for 20 consecutive days. Xanthotoxin or umbelliferone prevented cognitive deficits in the Morris water maze and object recognition tests. In parallel, xanthotoxin or umbelliferone reduced hippocampal acetylcholinestrase activity and malondialdehyde level. Moreover, xanthotoxin or umbelliferone increased glutathione content. These coumarins also modulated neuronal cell death by reducing the level of proinflammatory cytokines (tumour necrosis factor-alpha and interleukin-6), inhibiting the overexpression of inflammatory markers (nuclear factor κB [NF-κB] and cyclooxygenase II), and upregulating the expression of NF-κB inhibitor (IκB-α). Interestingly, xanthotoxin diminished phosphorylated JAK2 and phosphorylated STAT3 protein expression, while umbelliferone markedly replenished nuclear factor erythroid-derived 2-like 2 (Nrf2) and haem oxygenase-1 (HO-1) levels. The current study provides evidence for the protective effect of xanthotoxin and umbelliferone in STZ-induced cognitive dysfunction in rats. This effect may be attributed, at least in part, to inhibiting acetylcholinestrase and attenuating oxidative stress, neuroinflammation and neuronal loss.

Esculetin inhibits proliferation, migration, and invasion of clear cell renal cell carcinoma cells.

BACKGROUND: Esculetin, the main active ingredient in the Chinese herbal medicineCortex Fraxini, has been shown to possess antitumor activity. However, the effect of esculetin on clear cell renal cell carcinoma (ccRCC) has not been investigated. METHODS: MTS assays and colony formation assays were used to study the cytotoxicity of esculetin. The effects of esculetin on cell cycle and apoptosis were analyzed by flow cytometry. Western blot was used to detect cell cycle-, apoptosis-, and EMT-related proteins. Wound-healing assays and transwell assays were performed to study the effect of esculetin on cell migration and invasion in the ccRCC cell lines 786-O and SN12-PM6. RESULTS: Esculetin exerted cytotoxic activities in 786-O and SN12-PM6 cells in a dose- and time-dependent manner. The compound arrested the cell cycle in G0/G1 and G2/M phase with down-regulation of Cyclin D1, CDK4, CDK6, and c-Myc expression. Esculetin also induced apoptosis and the expression of cleaved caspase 3 increased. Additionally, esculetin significantly inhibited 786-O and SN12-PM6 cell migration and invasion, the expression of E-Cadherin increased, and the expression of N-cadherin and vimentin decreased. CONCLUSION: Taken together, these results suggest that esculetin inhibits proliferation, migration, and invasion of ccRCC and is a potential novel therapeutic agent for the treatment of ccRCC.

Umbelliferone modulates depression-like symptoms by altering monoamines in a rat post-traumatic stress disorder model.

Post-traumatic stress disorder (PTSD) is a debilitating psychological disease that is triggered by traumatic events. It is known to cause various complications, including anxiety and depression. Umbelliferone (UMB) is a natural product of the coumarin family. This substance has been reported to exert antioxidant, anti-inflammatory, neuroprotective, and other biological effects. We used the open field test (OFT) and the forced swimming test (FST) to examine the effects of UMB on depression-like symptoms in rats after exposure to a single prolonged stress (SPS), which led to dysregulated activation of the serotonergic system. Male rats were given UMB (20, 40, or 60 mg/kg, intraperitoneal injection) once daily for 14 days after exposure to an SPS. Daily UMB administration significantly improved depression-like behaviors on the FST, increased the number of lines crossed in the central zone of the OFT, and reduced freezing behavior in both contextual and cued fear conditioning. UMB treatment attenuated the SPS-induced decrease in serotonin (5-HT) concentrations in the hippocampus and amygdala. The increased 5-HT concentration during UMB treatment was partially due to a decrease in the ratio of 5-hydroxyindoleacetic acid/5-HT in the hippocampus of rats with PTSD. According to our results, UMB has an antidepressant effect in rats exposed to an SPS, suggesting that this natural product of the coumarin family can be used to effectively treat PTSD.

Anti-Hepatitis B Virus Activity of Esculetin from Microsorium fortunei In Vitro and In Vivo.

Coumarins are widely present in a variety of plants and have a variety of pharmacological activities. In this study, we isolated a coumarin compound from Microsorium fortunei (Moore) Ching; the compound was identified as esculetin by hydrogen and carbon spectroscopy. Its anti-hepatitis B virus (HBV) activity was investigated in vitro and in vivo. In the human hepatocellular liver carcinoma 2.2.15 cell line (HepG2.2.15) transfected with HBV, esculetin effecting inhibited the expression of the HBV antigens and HBV DNA in vitro. Esculetin inhibited the expression of Hepatitis B virus X (HBx) protein in a dose-dependent manner. In the ducklings infected with duck hepatitis B virus (DHBV), the levels of DHBV DNA, duck hepatitis B surface antigen (DHBsAg), duck hepatitis B e-antigen (DHBeAg), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) decreased significantly after esculetin treatment. Summing up the above, the results suggest that esculetin efficiently inhibits HBV replication both in vitro and in vivo, which provides an opportunity for further development of esculetin as antiviral drug.

Umbelliferone reduces the expression of inflammatory chemokines in HaCaT cells and DNCB/DFE-induced atopic dermatitis symptoms in mice.

Umbelliferone (UMB) is a coumarin derivative present in roots and barks of plants, such as Angelica decursiva, Artemisia capillaris, and orange. UMB has been previously reported to exhibit anti-inflammatory, anti-diabetic, and anti-cancer effects. However, the effect of UMB on atopic dermatitis (AD) remains unknown. The purpose of this study was to investigate the anti-atopic effects of UMB on 2,4-dinitrochlorobenzene (DNCB)- and house dust mite extract (Dermatophagoides farinae extract, DFE)-treated mice with AD-like skin lesions and on tumor necrosis factor (TNF)-α/interferon (IFN)-γ-treated HaCaT cells. In DNCB/DFE-treated mice, oral administration of UMB (20 and 40 mg/kg) for 28 days led to a significant decrease in ear thickness, spleen size and weight, serum levels of immunoglobulin E (IgE), IgG1, IgG2a, TNF-α, and interleukin 4 (IL-4), and mast cell infiltration; it also led to the suppression of pro-inflammatory cytokines and chemokines. In addition, UMB reduced the secretion of pro-inflammatory cytokines and chemokines in TNF-α/IFN-γ-treated HaCaT cells via regulation of MAPK, IkB-α/NF-κB, and STAT1 signaling pathways. Taken together, these results indicate that UMB ameliorates AD-associated symptoms and inflammation via regulation of various signaling pathways, suggesting that UMB might be a potential therapeutic agent of AD.

Umbelliferone ameliorates renal function in diabetic nephropathy rats through regulating inflammation and TLR/NF-κB pathway.

Diabetic nephropathy (DN) is a leading cause of renal failure, contributing to severe morbidity and mortality in diabetic patients. Umbelliferae (Umb) has been well characterized to exert protective effects in diabetes. However, the action and mechanism of Umb in DN remains unclear. In this work, we studied the effect of Umb in a streptozotocin (STZ)-induced DN rat model and explore its underlying mechanism. DN rats were treated withUmb (20, 40 mg·kg-1) orirbesartan (15 mg·kg-1) for 4 weeks. Levels of serum glucose, insulin, blood uric acid, creatinine, triglycerides (TG) and total cholesterol (TC) were measured bycommercial assay kits, respectively. Histopathological changes andinflammatory cytokine levels including IL-6, IL-1ß and TNF-α in the kidney were also evaluated. Alterations in the expression of podocin, CD2AP and TLR/NF-κB were assessed by western blotting. Our results showed that Umb reduced renal injury in DN rat model, as evidenced by the decrease in blood glucose, 24 h urinary protein, serum creatinine, and blood uric acid. Umb also significantly ameliorated the renal histopathological alteration, and down-regulated the expression of epithelial-to-mesenchymal transition-related molecular markers podocin and CD2AP. Moreover, Umb inhibited TLR2, TLR4, MyD88 expressions, NF-κB activation and considerably reduced levels of other downstream inflammatory molecules (TNF-α, IL-6, IL-1ß). These findings indicated that Umb improved renal function through regulating inflammation and TLR/NF-κB pathway, suggesting the potential efficacy of Umb in DN treatment.

The Inhibition Kinetics and Potential Anti-Migration Activity of NQO1 Inhibitory Coumarins on Cholangiocarcinoma Cells.

Altered expression of a cytosolic flavoenzyme NAD(P)H:quinone oxidoreductase-1 (NQO1) has been seen in many human tumors. Its remarkable overexpression in cholangiocarcinoma (CCA; an aggressive malignancy of the biliary duct system) was associated with poor prognosis and short survival of the patients. Inhibition of NQO1 has been proposed as a potential strategy to improve the efficacy of anticancer drugs in various cancers including CCA. This study investigated novel NQO1 inhibitors and verified the mechanisms of their enzyme inhibition. Among the different chemical classes of natural NQO1 inhibitors are coumarins, flavonoids, and triterpenoids. Coumarins are a group of particularly potent NQO1 inhibitors. The mechanisms and kinetics of enzyme inhibition of coumarin, aesculetin, umbelliferone, and scopoletin using the cell lysates as a source of NQO1 enzyme best fit with an uncompetitive inhibition model. Among the NOQ1 inhibitors tested in KKU-100 CCA cells, scopoletin and umbelliferone had the strongest inhibitory effect on this enzyme, while aesculetin and coumarin barely affected intracellular NQO1. All coumarins were further tested for cytotoxicity and anti-migration activity. At modest cytotoxic doses, scopoletin and umbelliferone greatly inhibited the migration of KKU-100 cells, whereas coumarin and aesculetin barely reduced cell migration. The anti-migration effect of scopoletin was associated with decreased ratio of matrix metalloproteinase 9/tissue inhibitors of metalloproteinases 1 ( MMP9/ TIMP1) mRNA. These findings suggest that natural compounds with potent inhibitory effect on intracellular NQO1 have useful anti-migration effects on CCA cells. In order to prove that the potent NQO1 inhibitor, scopoletin, is clinically useful in the enhancement of CCA treatment, additional in vivo studies to elucidate the mechanism of these effects are needed.

Esculetin from Fraxinus rhynchophylla attenuates atopic skin inflammation by inhibiting the expression of inflammatory cytokines.

Atopic dermatitis (AD) is a common chronic inflammatory skin disorder afflicting from infancy to adults with itching, scratching, and lichenification. We aimed to investigate the effects of esculetin from Fraxinus rhynchophylla on atopic skin inflammation. For induction of atopic skin inflammation, we exposed the ears of female BALB/c mice to house dust mite (Dermatophagoides farinae extract, DFE) and 2,4-dinitrochlorobenzene (DNCB) for 4 weeks. Oral administration of esculetin reduced the symptoms of DFE/DNCB-induced atopic skin inflammation, which were evaluated based on ear swelling and number of scratch bouts. The immunoglobulin (Ig) E, IgG2a, and histamine levels in serum were decreased and inflammatory cell infiltration in skin tissue was reduced by the esculetin. It suppressed production of Th1, Th2 and Th17-related cytokines such as tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-4, IL-13, IL-31 and IL-17 in the ear tissue. Furthermore, we investigated the effects of esculetin on activated keratinocytes, which are representative cells used for studying the pathogenesis of acute and chronic atopic skin inflammation. As results, esculetin suppressed gene expression of Th1, Th2 and Th17 cytokines and the activation of nuclear factor-κB and signal transducer and activator of transcription 1 in TNF-α/IFN-γ-stimulated keratinocytes. Taken together, these results imply that esculetin attenuated atopic skin inflammation, suggesting that esculetin could be a potential therapeutic candidate for the treatment of AD.

Effects of Viola mandshurica on Atherosclerosis and Hepatic Steatosis in ApoE[Formula: see text] via the AMPK Pathway.

Atherosclerosis was previously thought to be a disease that primarily involves lipid accumulation in the arterial wall. In this report, we investigated the effect of Viola mandshurica W. Becker (V. mandshurica) water extract on atherosclerosis in apolipoprotein E deficient (ApoE[Formula: see text]) mice. The administration of V. mandshurica to high-fat diet-fed mice reduced body weight, liver weight, and serum levels of lipids (total cholesterol, low-density lipoprotein-cholesterol, triglycerides), glucose, alanine transaminase, and aspartate transaminase. Histopathologic analyses of the aorta and liver revealed that V. mandshurica attenuated atherosclerotic lesions and reduced lipid accumulation, inflammatory responses and fatty acid synthesis. V. mandshurica also increased phosphorylation of adenosine monophosphate-activated protein kinase (AMPK), thereby reducing acetyl-CoA carboxylase (ACC) in liver tissue and inhibiting sterol regulatory element-binding protein 1c (SREBP-1c). V. mandshurica reduced protein expression levels of adhesion molecules (intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin) as well as ACC, fatty acid synthase, and SREBP-1c. In addition, quantitative analysis of V. mandshurica by high-performance liquid chromatography revealed the presence of esculetin and scopoletin. Esculetin and scopoletin reduced adhesion molecules in human aortic smooth muscle cells. Our results indicate that the anti-atherosclerotic effects of V. mandshurica may be associated with activation of the AMPK pathway. Therefore, AMPK-dependent phosphorylation of SREBP-1c by V. mandshurica may be an effective therapeutic strategy for combatting atherosclerosis and hepatic steatosis.

7, 8-Dihydroxycoumarin (daphnetin) protects INS-1 pancreatic ß-cells against streptozotocin-induced apoptosis.

BACKGROUND AND OBJECTIVE: Daphnetin (7, 8-dihydroxycoumarin), a natural coumarin compound, is known to exhibit antioxidant and anti-inflammatrory effects. However, the underlying mechanisms of its anti-apoptotic and antidiabetic effects yet not been examined. Therefore, the present work studied the anti-apoptotic and anti-diabetic effects of daphnetin by in vitro experiments. METHODS: The rat insulinoma (INS-1) cells were pre-treated with daphnetin at different concentrations (1, 10, 20 and 40µM) for 24h followed by exposition to streptozotocin (STZ) (3mM) for 12h. Effects of daphnetin and STZ on INS-1 cells were determined by MTT assay, glucose stimulated insulin secretion (GSIS) assay, lipid peroxidation, antioxidant status (SOD, CAT, GPx, and GST) Apoptosis staining (DAPI, Hoechst 33342, AO/EB and ROS) was performed by fluorescence microscopy, and Bcl-2, Bax and NF-κB protein expression was detected by Western blotting. RESULTS: MTT assay indicated that the viability of INS-1 cells was significantly reduced with exposure to STZ for 12h as compared to control cells, while pre-treated with daphnetin for 24h resulted in a significant improvement of cell viability. The effects daphnetin treatment in INS-1 cells on insulin secretion was tested and results showed that the pre-treatment of daphnetin could improve GSIS. Further, daphnetin pre-treatment significantly reduced the levels of lipid peroxidation markers and also improved antioxidant enzymes' activities in STZ-induced INS-1 cells. Western blotting assay revealed that daphnetin could suppress apoptosis through up-regulation of anti-apoptotic Bcl-2 protein expression and the down-regulation of pro-apoptotic Bax and nuclear factor NF-κB protein levels. CONCLUSION: The results showed that daphnetin might be used in treating diabetes due to its insulin stimulating property and subsequent regulation of apoptotic pathway.