Daphnetin alleviates silica-induced pulmonary inflammation and fibrosis by regulating the PI3K/AKT1 signaling pathway in mice

Silicosis is a hazardous occupational disease caused by inhalation of silica, characterized by persistent lung inflammation that leads to fibrosis and subsequent lung dysfunction. Moreover, the complex pathophysiology of silicosis, the challenges associated with early detection, and the unfavorable prognosis contribute to the limited availability of treatment options. Daphnetin (DAP), a natural lactone, has demonstrated various pharmacological properties, including anti-inflammatory, anti-fibrotic, and pulmonary protective effects. However, the effects of DAP on silicosis and its molecular mechanisms remain uncover. This study aimed to evaluate the therapeutic effects of DAP against pulmonary inflammation and fibrosis using a silica-induced silicosis mouse model, and investigate the potential mechanisms and targets through network pharmacology, proteomics, molecular docking, and cellular thermal shift assay (CETSA). Here, we found that DAP significantly alleviated silica-induced lung injury in mice with silicosis. The results of H&E staining, Masson staining, and Sirius red staining indicated that DAP effectively reduced the inflammatory response and collagen deposition over a 28-day period following lung exposure to silica. Furthermore, DAP reduced the number of TUNEL-positive cells, increased the expression levels of Bcl-2, and decreased the expression of Bax and cleaved caspase-3 in the mice with silicosis. More importantly, DAP suppressed the expression levels of NLRP3 signaling pathway-related proteins, including NLRP3, ASC, and cleaved caspase-1, thereby inhibiting silica-induced lung inflammation. Further studies demonstrated that DAP possesses the ability to inhibit the epithelial mesenchymal transition (EMT) induced by silica through the inhibition of the TGF-β1/Smad2/3 signaling pathway. The experimental results of proteomic analysis found that the PI3K/AKT1 signaling pathway was the key targets of DAP to alleviate lung injury induced by silica. DAP significantly inhibited the activation of the PI3K/AKT1 signaling pathway induced by silica in lung tissues. The conclusion was also verified by the results of molecular and CETSA. To further verify this conclusion, the activity of PI3K/AKT1 signaling pathway was inhibited in A549 cells using LY294002. When the A549 cells were pretreated with LY294002, the protective effect of DAP on silica-induced injury was lost. In conclusion, the results of this study suggest that DAP alleviates pulmonary inflammation and fibrosis induced by silica by modulating the PI3K/AKT1 signaling pathway, and holds promise as a potentially effective treatment for silicosis.

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.

Anticancer effect of umbelliferone on MKN-45 and MIA PaCa-2 cell lines

In this study, the anticancer activity of umbelliferone (7-hydroxycoumarin-UMB) was investigated in MKN-45 human gastric cancer and MIA PaCa-2 human pancreatic cancer cells. The cytotoxic effect of UMB on MKN-45 and MIA PaCa-2 cells was determined by WST-8 cell viability assay; the effect on colony formation and migration potential by colony forming assay and wound healing/cell migration assay. Apoptotic effect of UMB was determined by measuring the change in mitochondrial membrane potentials, reactive oxygen species levels, and Caspase-3 activities in cells. Anticancer drugs cisplatin and gemcitabine were used as positive controls in experiments, and NIH/Swiss 3 T3 mouse embryonic fibroblast cells were used as a healthy cell group. The results of this study showed that umbelliferone had a significant cytotoxic effect in MKN-45 and MIA PaCa-2 cells, especially after 72 h treatment, while its cytotoxic effect in NIH/3 T3 cells was low. Furthermore, UMB reduces significantly the potential of cells to colonize and migrate; it has been determined that it causes apoptosis by decreasing the mitochondrial membrane potential, increasing intracellular ROS levels and Caspase-3 activity. UMB was found to have more anticancer effect on MIA PaCa-2 cells compared to MKN-45 cells. This showed that UMB has a cell-selective effect.

Umbelliferone attenuates cisplatin-induced acute kidney injury by inhibiting oxidative stress and inflammation via NRF2

In this study, we investigated the nephroprotective effects of Umbelliferone (UMB) against cisplatin-induced acute kidney injury (AKI). C57BL/6J mice were treated with cisplatin via a single intraperitoneal injection (25 mg/kg) with or without UMB (40 mg/kg/day) by gavage. Renal function, apoptosis, oxidative stress, inflammation, and mitochondrial function were analyzed to evaluate kidney injury. In vitro, human proximal tubule epithelial cells were treated with cisplatin, with or without UMB, for 24 h. Western blotting and immunohistochemistry were performed to explore the mechanisms underlying the nephroprotective effects of UMB. Cisplatin-induced renal dysfunction, including increases in blood urea nitrogen, serum creatinine, and renal tubular injury indices (NGAL and KIM-1), were significantly attenuated by UMB treatment, along with renal phenotypic changes and renal tubular injury, as evidenced by improved renal histology. Moreover, NRF2 was activated by UMB pretreatment, along with the inhibition of oxidative stress and inflammatory response, as evidenced by decreased levels of antioxidant genes and inflammatory cytokines in cisplatin-induced AKI. Our results demonstrate that UMB can protect against cisplatin-induced nephrotoxicity, which is mediated by the NRF2 signaling pathway via antioxidant and anti-inflammatory activities, suggesting the clinical potential of UMB for the treatment of AKI.

Network pharmacology and molecular docking reveal potential mechanism of esculetin in the treatment of ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease of the colonic mucosa. Esculetin is a type of natural coumarin that has many pharmacological activities such as antioxidant, anticancer, anti-inflammatory, etc. A previous study showed that esculetin improved intestinal inflammation and reduced serum proinflammatory cytokines in UC. The present study aimed to utilize network pharmacology and molecular docking to explore the potential mechanism of esculetin against UC. The potential gene targets of esculetin were predicted through SwissTargetPrediction and Super-PRED web servers. UC-related genes were obtained from DisGeNet, OMIM, and GeneCards databases. The overlap between gene targets of esculetin and UC-related genes were identified as the potential targets of esculetin against UC. The interaction between these overlapping genes was analyzed by the STRING database and the core genes were identified by Cytoscape platform. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis of the core genes were then performed. And the results of these analyses were further confirmed through molecular docking. A total of 50 overlapping genes were identified as the potential action targets of esculetin against UC. Among them, 10 genes (AKT1, STAT1, CCND1, SRC, PTGS2, EGFR, NFKB1, ESR1, MMP9, SERPINE1) were finally identified as the core genes. The Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis results showed that the top signaling pathway associated with the core genes of esculetin against UC was the prolactin (PRL) signaling pathway. Molecular docking results showed that esculetin has a strong binding affinity to the core genes, as well as PRL and prolactin receptor. This study suggests that esculetin may have a crucial impact on UC through the PRL signaling pathway and provides insights into the potential mechanism of esculetin in the treatment of UC, which may shed light on the mechanism and treatment of UC.

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.

Pharmacological and Therapeutic Applications of Esculetin

Esculetin is a coumarin compound, which belongs to the class of benzopyrone enriched in various plants such as Sonchus grandifolius, Aesculus turbinata, etc. Free radicals lead to the development of oxidative stress causing inflammation, arthritis, cancer, diabetes, fatty liver disease, etc. These further reduce the efficacy of anticancer drugs, activate inflammatory signaling pathways, degrade joints and cartilage, and disrupt the glycemic index and normal function of liver enzymes. For instance, the current treatment modalities used in arthritis such as non-steroidal anti-inflammatory drugs, disease-modifying anti-rheumatoid drugs, and lipoxygenase inhibitors present limited efficacy and adverse effects. Thus, there is a constant need to find newer and safer alternatives. Esculetin has an immense antioxidative potential thereby alleviating arthritis, diabetes, malignancies, and hepatic disorders. Structurally, esculetin contains two hydroxyl groups, which enhance its ability to function as an antioxidant by inhibiting oxidative stress in pathological conditions. Leukotriene B4 synthesis, NF-κB and MPAK pathway activation, and inflammatory cytokine production are the main causes of bone and joint deterioration in arthritis, whereas esculetin treatment reverses these factors and relieves the disease condition. In contrast, lipid peroxidation caused by upregulation of TGF-β-mediated expression and dysfunction of antioxidant enzymes is inhibited by esculetin therapy, thus reducing liver fibrosis by acting on the PI3K/FoxO1 pathway. Therefore, targeting NF-κB, pro-inflammatory cytokines, TGF-β and oxidative stress may be a therapeutic strategy to alleviate arthritis and liver fibrosis.

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.

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

Influence of Umbelliferone on the Anticonvulsant and Neuroprotective Activity of Selected Antiepileptic Drugs: An In Vivo and In Vitro Study

Umbelliferone (7-hydroxycoumarin; UMB) is a coumarin with many biological properties, including antiepileptic activity. This study evaluated the effect of UMB on the ability of classical and novel antiepileptic drugs (e.g., lacosamide (LCM), levetiracetam (LEV), phenobarbital (PB) and valproate (VPA)) to prevent seizures evoked by the 6-Hz corneal-stimulation-induced seizure model. The study also evaluated the influence of this coumarin on the neuroprotective properties of these drugs in two in vitro models of neurodegeneration, including trophic stress and excitotoxicity. The results indicate that UMB (100 mg/kg, i.p.) significantly enhanced the anticonvulsant action of PB (p < 0.01) and VPA (p < 0.05), but not that of LCM orLEV, in the 6-Hz test. Whether alone or in combination with other anticonvulsant drugs (at their ED50 values from the 6-Hz test), UMB (100 mg/kg) did not affect motor coordination; skeletal muscular strength and long-term memory, as determined in the chimney; grip strength; or passive avoidance tests, respectively. Pharmacokinetic characterization revealed that UMB had no impact on total brain concentrations of PB or VPA in mice. The in vitro study indicated that UMB has neuroprotective properties. Administration of UMB (1 µg/mL), together with antiepileptic drugs, mitigated their negative impact on neuronal viability. Under trophic stress (serum deprivation) conditions, UMB enhanced the neurotrophic abilities of all the drugs used. Moreover, this coumarin statistically enhanced the neuroprotective effects of PB (p < 0.05) and VPA (p < 0.001) in the excitotoxicity model of neurodegeneration. The obtained results clearly indicate a positive effect of UMB on the anticonvulsant and neuroprotective properties of the selected drugs.

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.

Exploring cardioprotective potential of esculetin against isoproterenol induced myocardial toxicity in rats: in vivo and in vitro evidence

BACKGROUND

Esculetin is a natural coumarin derivative from various plants with multiple pharmacological effects. Hence, the present study was undertaken to explore the cardio protective potential of esculetin against isoproterenol induced myocardial toxicity in rats.

METHODS

The treatment schedule was fixed for 28 days and the rats were divided into five groups of six each. Rats of group I received the normal saline and served as normal control, group II was received ISO (100 mg/kg body weight) for last two consecutive days of the study and served as disease control. Groups III and IV received esculetin 10 and 20 mg/kg body weight respectively once a day per oral for 28 days along with ISO for last two consecutive days of the study. Cardiac biomarkers such as CK-MB and LDH, membrane bound Na+ /K+ ATPases activity, myocardial lysosomal enzymes activity and tissue antioxidants status were estimated in the heart tissue samples. The histopathological changes in the myocardium were also assessed. Further, DPPH assay was done to evaluate the free radicals scavenging potential of esculetin. Cytoxicity assay, intracellular ROS levels by DCFDA assay and m-RNA expression of TNF-α, IL-6 and NF-κB by quantitative RT-PCR in H9c2 cell lines.

RESULTS

The increased levels of CK-MB, LDH, LPO, myocardial lysosomal enzymes and membrane bound Na+ /K+ ATPase levels by ISO administration was significantly increased with concomitant decrease in tissue antioxidant enzymes such as GSH, Catalase, and SOD. Pre-treatment with esculetin for 28 days has significantly decreased the levels of cardiac bio-markers, lysosomal enzymes, membrane bound Na+ /K+ ATPase levels as well as Lipid peroxides which is in contrary to the ISO group. Amelioration of the antioxidant levels were also found in esculetin treated groups. Histopathological examination of heart reveals that myocardial degeneration, mononuclear cell infiltration was noticed in ISO treated rats, whereas the same was restored with esculetin treatment. In H9C2 cell lines esculetin could effectively reduced intracellular ROS inhibition and m-RNA expression of pro-inflammatory cytokines including TNF-α, IL-6 and NF-κB to prevent apoptosis or cell necrosis.

CONCLUSION

The study provides the evidence of cardioprotective potentials of esculetin against isoproterenol induced myocardial infarction by antioxidant and myocardial membrane stabilization along with in vitro protection from arsenic induced ROS cell necrosis or apoptosis in H9C2 cells.

Mechanisms of the Procognitive Effects of Xanthotoxin and Umbelliferone on LPS-Induced Amnesia in Mice

Neuroinflammation plays an essential role in the pathogenesis of neurodegenerative diseases such as Alzheimer's disease. Although coumarins have been shown to improve cognitive function in animal models and exert anti-inflammatory effects in cell cultures, the exact mechanism of their neuroprotective effects has not yet been fully elucidated. The present study aimed to investigate the neuroprotective effects of xanthotoxin (furanocoumarin) and umbelliferone (simple coumarin) in lipopolysaccharide-induced cognitive dysfunction in mice. For evaluation memory and learning processes, a passive avoidance test was used. Furthermore, acetylcholinesterase level and impact on the tumor necrosis factor α, interleukin 10 levels in the whole brain, and cyclooxygenase-II in hippocampus was established. Subchronic administration of both coumarins (15 mg/kg) enhanced the learning and memory function, but only the xanthotoxin improved cognitive processes impaired by lipopolysaccharide (0.8 mg/kg) administration. Behavioral results stay in line with acetylcholinesterase level in the brain. A statistically significant decrease in the level of tumor necrosis factor α and cyclooxygenase-II in lipopolysaccharide-treated rodents after coumarins' administration was observed. Together, our findings demonstrate that both coumarins improved cognitive functions, but only xanthotoxin significantly enhanced the learning and memory function and reduced the level of acetylcholinesterase in lipopolysaccharide-treated mice. This effect may suggest that only furanocoumarin-xanthotoxin attenuates neuroinflammation and enhances cholinergic neurotransmission, thus it can be a potential remedy with procognitive potential effective in treatment of neuroinflammatory disease.

Skimmetin/osthole mitigates pain-depression dyad via inhibiting inflammatory and oxidative stress-mediated neurotransmitter dysregulation

Pain and depression are often co-existing pathological states that promote mutual severity resulting in limited efficacy of current treatment strategies. Thus, there is a need to develop an efficacious alternate treatment regimen for pain-depression dyad. Skimmetin and osthole are molecules of natural origin that have been explored for an anti-hyperglycemic, anti-bacterial, anti-fungal, and anti-diabetic activities in preclinical studies. in animal models. The current study has been designed to explore the beneficial effect of skimmetin/osthole in reserpine-induced pain-depression dyad in mice. Female Swiss albino mice (n = 6) were challenged with reserpine (0.5 mg/kg s.c.) for the first 3 days to induce a pain-depression dyad-like state. Skimmetin (10 mg/kg i.p.) and osthole (10 mg/kg i.p.) were administered for 5 days consecutively, starting from the first day of study. Reserpine treatment significantly reduced the pain threshold in the pressure application measurement (PAM) and electronic von frey (eVF) test. In forced swim test (FST) and Morris water maze (MWM) test mice displayed an increased immobility time and latency to reach platform respectively. Biochemical results showed an increased level of TNF-α, IL-1β, TBARS, glutamate, and reduced level of GSH, norepinephrine, and serotonin in the reserpine treated group. Reserpine treatment also increased brain MAO-A activity. Skimmetin/osthole treatment was found to attenuate the behavioral and biochemical alterations induced by reserpine. The results of the current investigation delineated that skimmetin/osthole may exert anti-nociceptive, anti-depressant, and improved cognition via inhibiting inflammatory and oxidative stress-mediated neurotransmitter dysregulation.

Multiple-Purpose Connectivity Map Analysis Reveals the Benefits of Esculetin to Hyperuricemia and Renal Fibrosis

Hyperuricemia (HUA) is a risk factor for chronic kidney disease (CKD). Serum uric acid (SUA) levels in CKD stage 3–4 patients closely correlate with hyperuricemic nephropathy (HN) morbidity. New uric acid (UA)-lowering strategies are required to prevent CKD. The multiple-purpose connectivity map (CMAP) was used to discover potential molecules against HUA and renal fibrosis. We used HUA and unilateral ureteral occlusion (UUO) model mice to verify renoprotective effects of molecules and explore related mechanisms. In vitro experiments were performed in HepG2 and NRK-52E cells induced by UA. Esculetin was the top scoring compound and lowered serum uric acid (SUA) levels with dual functions on UA excretion. Esculetin exerted these effects by inhibiting expression and activity of xanthine oxidase (XO) in liver, and modulating UA transporters in kidney. The mechanism by which esculetin suppressed XO was related to inhibiting the nuclear translocation of hexokinase 2 (HK2). Esculetin was anti-fibrotic in HUA and UUO mice through inhibiting TGF-β1-activated profibrotic signals. The renoprotection effects of esculetin in HUA mice were associated with lower SUA, alleviation of oxidative stress, and inhibition of fibrosis. Esculetin is a candidate urate-lowering drug with renoprotective activity and the ability to inhibit XO, promote excretion of UA, protect oxidative stress injury, and reduce renal fibrosis.

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.

Esculetin, a Coumarin Derivative, Prevents Thrombosis: Inhibitory Signaling on PLCγ2-PKC-AKT Activation in Human Platelets

Esculetin, a bioactive 6,7-dihydroxy derivative of coumarin, possesses pharmacological activities against obesity, diabetes, renal failure, and cardiovascular disorders (CVDs). Platelet activation plays a major role in CVDs. Thus, disrupting platelet activation represents an attractive therapeutic target. We examined the effect of esculetin in human platelet activation and experimental mouse models. At 10–80 μM, esculetin inhibited collagen- and arachidonic acid-induced platelet aggregation in washed human platelets. However, it had no effects on other agonists such as thrombin and U46619. Esculetin inhibited adenosine triphosphate release, P-selectin expression, hydroxyl radical (OH·) formation, Akt activation, and phospholipase C (PLC)γ2/protein kinase C (PKC) phosphorylation, but did not diminish mitogen-activated protein kinase phosphorylation in collagen-activated human platelets. Platelet function analysis indicated that esculetin substantially prolonged the closure time of whole blood. In experimental mice, esculetin significantly increased the occlusion time in thrombotic platelet plug formation and reduced mortality associated with acute pulmonary thromboembolism. However, it did not prolong the bleeding time. This study demonstrates that esculetin inhibits human platelet activation via hindering the PLCγ2–PKC cascade, hydroxyl radical formation, Akt activation, and ultimately suppressing platelet activation. Therefore, esculetin may act as an essential therapeutic agent for preventing thromboembolic diseases.

7, 8-Dihydroxycoumarin (daphnetin) protects INS-1 pancreatic β-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.

7,8-dihydroxycoumarin has a dual mechanism of action in hepatic ischemia reperfusion injury

The present study was designed to investigate the protective effect of 7,8-dihydroxycoumarin on hepatic ischemia/reperfusion (I/R) injury in the rats. The rats were divided in three groups of 10 each; normal control, untreated and the 7,8-dihydroxycoumarin treatment groups. The rats in the treatment group received 7,8-dihydroxycoumarin at doses of 15 mg/kg body weight 1 h prior to ischemia and then daily for 2 days. The animals were sacrificed after 1, 12, 24, 36, and 48 h of reperfusion. The results revealed that 7,8-dihydroxycoumarin protected the liver against I/R injury via inhibition of inflammatory response at the early stage (0-24 h). However, in 7,8-dihydroxycoumarin treatment group autophagy was inhibited resulting in intensified I/R injury following 36 h of reperfusion. 7,8-dihydroxycoumarin treatment caused reduction in the level of serum aminotransferase, liver inflammatory cytokines and showed minor liver histopathologic alterations. However, after 36 h of reperfusion treatment group showed similar I/R injury as that of untreated group. It was observed that 7,8-dihydroxycoumarin enhanced the activation of mitogen-activated protein kinase, decreased nuclear release of high-mobility group box 1 and production of inflammatory cytokines. After 36 h 7,8-dihydroxycoumarin promoted hepatic injury through suppression of autophagy and induction of hepatic apoptosis. Therefore, 7,8-dihydroxycoumarin exhibits inhibitory effect on hepatic ischemia during 0-24 h but causes its promotion after 36 h.

Antioxidant and intestinal anti-inflammatory effects of plant-derived coumarin derivatives

BACKGROUND

Coumarins, also known as benzopyrones, are plant-derived products with several pharmacological properties, including antioxidant and anti-inflammatory activities. Based on the wide distribution of coumarin derivatives in plant-based foods and beverages in the human diet, our objective was to evaluate both the antioxidant and intestinal anti-inflammatory activities of six coumarin derivatives of plant origin (scopoletin, scoparone, fraxetin, 4-methyl-umbeliferone, esculin and daphnetin) to verify if potential intestinal anti-inflammatory activity was related to antioxidant properties.

METHODS

Intestinal inflammation was induced by intracolonic instillation of TNBS in rats. The animals were treated with coumarins by oral route. The animals were killed 48 h after colitis induction. The colonic segments were obtained after laparotomy and macroscopic and biochemical parameters (determination of glutathione level and myeloperoxidase and alkaline phosphatase activities) were evaluated. The antioxidant properties of these coumarins were examined by lipid peroxidation and DPPH assays.

RESULTS

Treatment with esculin, scoparone and daphnetin produced the best protective effects. All coumarin derivatives showed antioxidant activity in the DPPH assay, while daphnetin and fraxetin also showed antioxidant activity by inhibiting lipid peroxidation. Coumarins, except 4-methyl-umbeliferone, also showed antioxidant activity through the counteraction of glutathione levels or through the inhibition of myeloperoxidase activity.

DISCUSSION

The intestinal anti-inflammatory activity of coumarin derivatives were related to their antioxidant properties, suggesting that consumption of coumarins and/or foods rich in coumarin derivatives, particularly daphnetin, esculin and scoparone, could prevent intestinal inflammatory disease.

Mechanism of anti-inflammatory activity of umbelliferone 6-carboxylic acid isolated from Angelica decursiva

AIMS OF THE STUDY

We recently reported the potential antioxidant and anti-inflammatory activities of umbelliferone 6-carboxylic acid (UMC) isolated from the whole plants of Angelica decursiva. In this study, we elucidated the anti-inflammatory mechanisms of UMC in vitro and in vivo.

METHODS

The inhibitory effects of UMC on the production of nitric oxide (NO), prostaglandin E(2) (PGE(2)), and tumor necrosis factor-α (TNF-α), the expression of nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), the activation of nuclear factor kappa B (NF-κB) were evaluated using lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. The reactive oxygen species (ROS) generation inhibitory activity of UMC was evaluated using t-butyl hydroperoxide (t-BHP)-induced RAW 264.7 cells. Furthermore, the in vivo anti-inflammatory activity of UMC was evaluated using carrageenan induced mouse paw edema model.

RESULTS

UMC dose-dependently inhibited NO and PGE(2) production by down-regulating iNOS and COX-2 protein expression in LPS-stimulated RAW 264.7 macrophages. UMC also suppressed the production of the proinflammatory cytokine TNF-α in LPS stimulated RAW 264.7 cells in a concentration dependent manner. In addition, UMC dose-dependently prevented LPS-induced nuclear translocation of NF-κB in RAW 264.7 macrophages. Furthermore, UMC exhibited the inhibitory activity against t-BHP-induced ROS generation in RAW 264.7 cells with an IC(50) value of 705.1 μg/ml. Moreover, UMC inhibited λ-carrageenan induced mouse paw edema by 70.40 and 60.20% at doses of 50 and 25 mg/kg body weight, respectively.

CONCLUSION

The combined results of this study indicate that UMC is an important anti-inflammatory constituent of A. decursiva and its anti-inflammatory effect was due to its ability to inhibit the production of inflammatory mediators via inhibition of NF-κB activation pathway.

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.

Suppression of TNBS-induced colitis in rats by 4-methylesculetin, a natural coumarin: comparison with prednisolone and sulphasalazine

The aim of the present study was to compare the effects of the 4-methylesculetin with those produced by prednisolone and sulphasalazine and to elucidate the mechanisms involved in its action. Colitis was induced in rat by instillation of trinitrobenzenesulphonic acid (TNBS). The colon damage was evaluated using macroscopic, microscopic and biochemical analysis. In addition, in vitro studies were performed to evaluate cytokine production in cell cultures using the murine macrophage cell line RAW264.7, mouse splenocytes and the human colonic epithelial cell line Caco-2. 4-Methylesculetin produced a reduction of the macroscopic damage score and the recovery of the intestinal cytoarchitecture. These effects were associated with a prevention of the GSH depletion and an inhibition in AP activity. After colitis relapse, 4-methylesculetin improved the colonic inflammatory status as evidenced by histological findings, with a reduction in apoptosis, as well as biochemically by inhibition of colonic myeloperoxidase, alkaline phosphatase and metalloproteinase 9 activities. Paired with this inhibitive activity, there was a decrease in malondialdehyde content and in IL-1β levels. In vitro assays revealed that 4-methylesculetin promoted an inhibition in IL-1β, IL-8, IL-2 and IFN-γ production in cell cultures. In conclusion, 4-methylesculetin showed similar efficacy to that obtained with either prednisolone or sulphasalazine, both in the acute phase of colitis as well as following a curative protocol. The intestinal anti-inflammatory activity by 4-methylesculetin is likely related to its ability in reduce colonic oxidative stress and inhibit pro-inflammatory cytokine production.

An in vivo analysis of the therapeutic and synergistic properties of Chinese medicinal formula Yin-Chen-Hao-Tang based on its active constituents

6,7-Dimethylesculetin (D), geniposide (G) and rhein (R) are the three major active ingredients of Yin-Chen-Hao-Tang (YCHT), a famous Chinese herbal formula, which has been shown to be clinically effective for treating hepatic injury (HI) syndrome. The present study was conducted to investigate the therapeutic and synergistic effects of COC (combination of D, G and R) on HI rats by combining pharmacokinetic with biochemical analysis strategy. Plasma was analyzed by using reversed-phase high performance liquid chromatography (RP-HPLC). Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) models were built to evaluate the therapeutic and synergistic effects of COC at the biochemical level. Here, we report that the COC combination could increase the plasma level, slow elimination rate, exert a more robust therapeutic effect than any one or two of the three individual compounds by hitting multiple targets in a rat model of HI. Overall, this beneficially accounts for the popular view that traditional Chinese medicine (TCM) formula usually takes multi-component to exert their therapeutic effects. We suggest that dissecting the mode of action of clinically effective formula to be capable of producing a sufficient effect at low doses.

Esculetin induced changes in Mmp13 and Bmp6 gene expression and histone H3 modifications attenuate development of glomerulosclerosis in diabetic rats

Esculetin, an antioxidant, has been used in the treatment of a variety of diseases. This study aimed to investigate the protective effect of esculetin in attenuating streptozotocin (STZ)-induced type I diabetic nephropathy and to understand the molecular mechanism involved in it. Sprague-Dawley rats were rendered diabetic using a single dose of STZ (55 mg/kg, i.p.). Protein expression of PPARγ and transforming growth factor-β1 (TGF-β1) was detected by immunoblotting and immunohistochemistry respectively. RNA expression levels of Mmp13 and Bmp6 were detected by RT-PCR analysis. In diabetic rats, esculetin treatment resulted in a significant decrease in blood glucose, blood urea nitrogen, and plasma creatinine and increase in plasma albumin levels. Esculetin treatment attenuates the downregulation of PPARγ in diabetic kidney, which in turn blocks the TGF-β1-mediated fibronectin expression. In addition, it attenuates the decrease in mono-methylation (K4) and acetylation of histone H3 in diabetic kidney. RT-PCR analysis revealed that esculetin treatment provides protection by decreasing antifibrotic Bmp6 and increasing fibrogenic Mmp13 mRNA expression in diabetic kidney. This is the first report to show that protection observed by esculetin treatment involves alteration in mRNA expression of Mmp13 and Bmp6 genes either directly via altered histone H3 modifications or indirectly by inhibiting the PPARγ/TGF-β1 pathway.

Mechanisms involved in the antinociceptive effects of 7-hydroxycoumarin

7-Hydroxycoumarin (umbelliferone, 1), the main metabolite of coumarin, has been reported to produce potent antinociceptive effects in animal models of pain. However, the biochemical events involved in antinociception mediated by 1 are currently not well understood. In the present study, the mechanisms by which 1 exerts its pharmacological actions were investigated. Acute pretreatment of mice with 1 produced a long-lasting antinociceptive effect against complete Freund's adjuvant (CFA)-induced hyperalgesia. The subchronic administration of 1 inhibited CFA-induced hyperalgesia and paw edema, while it did not cause any apparent toxicity. Another set of experiments showed that 1 inhibited carrageenan-induced mechanical hyperalgesia, but not mechanical hyperalgesia induced by prostaglandin E(2) (PGE(2)), suggesting that it acts upstream of PGE(2.) Treatment with 1 was able to prevent the plantar tissue neutrophil influx induced by local inflammatory stimuli. In addition, 1 exhibited inhibitory effects on the release of hyperalgesic cytokines (TNF-α and IL-1β) and the production of PGE(2), a directly acting hyperalgesic mediator. The present results suggest that the antinociceptive effect of 1 is correlated with the inhibition of neutrophil migration, cytokine release, and PGE(2) production and are supportive of the further investigation of the therapeutic potential of 1 to control inflammatory pain.

Anti-breast cancer potential of SS5020, a novel benzopyran antiestrogen

Treatment with tamoxifen (TAM) increases the risk of developing endometrial cancer in women. The carcinogenic effect is thought to involve initiation and/or promotion resulting from DNA damage induced by TAM as well as its estrogenic action. To minimize this serious side-effect while increasing the anti-breast cancer potential, a new benzopyran antiestrogen, 2E-3-{4-[(7-hydroxy-2-oxo-3-phenyl-2H-chromen-4-yl)-methyl]-phenyl}-acrylic acid (SS5020), was synthesized. Unlike TAM, SS5020 exhibits no genotoxic activity to damage DNA. Furthermore, SS5020 does not present significant uterotrophic potential in rats; in contrast, the structurally related compounds, TAM, toremifene, raloxifene (RAL) and SP500263 all have uterotrophic activity. At the human equivalent molar dose of TAM (0.33 or 1.0 mg/kg), SS5020 had much stronger antitumor potential than those same antiestrogens against 7,12-dimethylbenz(a)anthracene-induced mammary carcinoma in rats. The growth of human MCF-7 breast cancer xenograft implanted into athymic nude mice was also effectively suppressed by SS5020. SS5020, lacking genotoxic and estrogenic actions, could be a safer and stronger antiestrogen alternative to TAM and RAL for breast cancer therapy and prevention.

Fraxinus rhynchophylla ethanol extract attenuates carbon tetrachloride-induced liver fibrosis in rats via down-regulating the expressions of uPA, MMP-2, MMP-9 and TIMP-1

AIM OF THE STUDY

To investigate the effect of Fraxinus rhynchophylla ethanol extract (FR(EtOH)) on liver fibrosis induced by carbon tetrachloride (CCl(4)) in rats.

MATERIALS AND METHODS

Rat hepatic fibrosis was induced by oral administration of CCl(4). Sixty SD rats were divided randomly into 6 groups: control, CCl(4) group, silymarin group and three FR(EtOH)-treated groups. Except for the rats in control group, all rats were administered orally with CCl(4) (20%, 0.2 mL/100g body weight) twice a week for 8 weeks. Rats in FR(EtOH) groups were treated daily with FR(EtOH) (0.1, 0.5 and 1.0 g/kg, p.o.) throughout the whole experimental period. Liver function parameters (such as activities of serum GOT and GPT levels), activities of liver anti-oxidant enzymes (such as catalase, SOD, GPx) and expressions of uPA, tPA, MMP-2, MMP-9 and TIMP-1, -2, -3, -4 in the liver fibrosis pathway were detected.

RESULTS

The results showed that FR(EtOH) (0.1, 0.5 and 1.0 g/kg BW) significantly reduced the elevated activities of sGOT and sGPT caused by CCl(4). FR(EtOH) (0.1 and 0.5 g/kg BW) and significantly increased the activities of GSH-Px. The histopathological study showed that FR(EtOH) (0.1 and 0.5 g/kg BW) reduced the incidence of liver lesions, including hepatic cells cloudy swelling, lymphocytes infiltration, cytoplasm vacuolization hepatic necrosis and fibrous connective tissue proliferated induced by CCl(4) in rats. In our study it was showed that CCl(4)-treated group significantly increased the protein levels of uPA, MMP-2, MMP-9 and TIMP-1. FR(EtOH) (0.1 and 0.5 g/kg BW) could inhibit the protein levels of uPA, MMP-2, MMP-9 and TIMP-1. Finally, the amount of esculetin in the FR(EtOH) was 33.54 mg/g extract.

CONCLUSIONS

Oral administration of FR(EtOH) significantly reduces CCl(4)-induced hepatic fibrosis in rats, probably by exerting a protective effect against hepatocellular fibrosis by its free radical scavenging ability. FR(EtOH) down-regulated the expressions of uPA, MMP-2 and MMP-9 in CCl(4)-induced liver fibrosis in rats.

Modulation of cytokine production by 7-hydroxycoumarin in vitro and its efficacy against influenza infection in mice

We previously demonstrated that 7-hydroxycoumarin (7HC) was effective in reducing proinflammatory cytokine production in lipopolysaccharide-exposed macrophage-like P388D1 cells and fever production by suppressing the increase in interleukin (IL)-1alpha production in an influenza virus-intranasal infection model in mice. In this study, we assessed the effects of modulation of cytokine production by 7HC on influenza virus infection in relation to its efficacy in influenza virus-infected mice. 7HC was confirmed to suppress proinflammatory cytokine levels in P388D1 cells due to influenza virus infection. In the murine infection model, oral administration of 7HC (30 mg/kg) was significantly effective in reducing the weight loss of infected mice and virus titers in the bronchoalveolar lavage fluid (BALF) of lungs and in prolonging survival times without toxicity. The rise of proinflammatory and Th1 cytokine (IL-12 and interferon-gamma) production in the BALF from infected mice was significantly suppressed by 7HC at two and four days post-infection, respectively. This suppression correlated with the reduction of virus titers and diminution of lung consolidation. Because 7HC did not exhibit direct anti-influenza virus activity in vitro, 7HC was suggested to suppress pneumonia in influenza virus-infected mice through suppression of the cytokine production induced by infection.

Effect of Umbelliferone on Tail Tendon Collagen and Haemostatic Function in Streptozotocin-Diabetic Rats

Diabetes mellitus is known to affect collagen in various tissues. Umbelliferone (7-hydroxycoumarin), a natural antioxidant and benzopyrone, is found in golden apple (Aegle marmelos Correa) and bitter orange (Citrus aurantium). Plant-derived phenolic coumarins have been shown to act as dietary antioxidants. In this study, we have investigated the influence of umbelliferone on collagen content and its effects on the tail tendon in streptozotocin-diabetic rats. Male albino Wistar rats (180-200 g) were made diabetic by intraperitoneal administration of streptozotocin (40 mg/kg). Normal and diabetic rats were treated with umbelliferone for 45 days. Diabetic rats had increased glucose and decreased insulin levels. Tail tendons of diabetic rats had increased total collagen, glycation and fluorescence, and decreased levels of neutral, acid and pepsin-soluble collagens. We have studied the effect of umbelliferone on haemostatic function because umbelliferone is also a coumarin derivative like the anticoagulant, warfarin. Diabetic rats had a significant decrease in prothrombin, clotting and bleeding time, and treatment with umbelliferone made these parameters almost normal. Our results show that umbelliferone controls glycaemia and has a beneficial effect on collagen content and its properties, i.e. collagen related parameters, in the tail tendon, which indicates recovery from the risk (recovery of animals from the risk of complications) of collagen-mediated diabetic polyneuropathy and diabetic nephropathy.

Antitumor and immunomodulatory effect of coumarin and 7-hydroxycoumarin against Sarcoma 180 in mice

The antitumor effect of peroral treatment with coumarin and its main metabolite in humans 7-hydroxycoumarin (7-OHC) against Sarcoma 180 in mice was studied. Both agents inhibited tumor growth and increased survival time of tumor-bearing animals. The antitumor effect was better when coumarins were administered prior to tumor inoculation suggesting that the immunomodulatory potential of coumarins might exceed their well-known direct cytostatic activity. The additive effect of coumarins in combination with a suboptimal LPS dose in tumor growth inhibition was demonstrated. Coumarin treatment enhanced the macrophage migration activity in the presence and absence of LPS and increased nitric oxide release. In vitro, coumarins induced IL-12 in murine macrophages and additively increased the LPS-induced IL-12 release. These data indicate that the immunomodulatory activity of coumarins contributes to their direct cytostatic effect and demonstrate their potential to combine as immunostimulators with other antitumor agents.

Antihyperglycemic Effect of Umbelliferone in Streptozotocin-Diabetic Rats

The present study was designed to investigate the antihyperglycemic effect of Umbelliferone (UMB) in normal and streptozotocin (STZ)-diabetic rats. Diabetes was induced in adult male albino rats of the Wistar strain, weighing 180-200 g, by administration of STZ (40 mg/kg of body weight) intraperitoneally. Diabetic rats showed an increase in levels of blood glucose and glycosylated hemoglobin (HbA(1c)) and activities of gluconeogenic enzymes such as glucose-6-phosphatase and fructose-1,6-bisphosphatase, and a decrease in levels of plasma insulin, hemoglobin (Hb), and liver glycogen and activities of glucokinase and glucose-6-phosphate dehydrogenase. Intraperitoneal administration of UMB (10, 20, and 30 mg/kg of body weight) and glibenclamide (600 micro g/kg of body weight) in 10% dimethyl sulfoxide dissolved in water, for 45 days, produced significantly decreased levels of blood glucose and HbA(1c) and activities of glucose-6-phosphatase and fructose-1,6-bisphosphatase, while elevating levels of plasma insulin, Hb, and liver glycogen and activities of glucokinase and glucose-6-phosphate dehydrogenase to near normal levels in STZ-diabetic rats when compared with normal control rats. Normal rats treated with UMB (30 mg/kg of body weight) also showed a significant effect on glycemic control. Thus, our results show that UMB at 30 mg/kg of body weight possesses a promising antihyperglycemic effect that is comparable with glibenclamide.

Antihyperlipidemic and antidiabetic effects of umbelliferone in streptozotocin diabetic rats

The aim of the study was to evaluate blood glucose and lipid lowering effects of Umbelliferone (UMB) in streptozotocin (STZ) diabetic rats. Male albino Wistar rats (180 to 200 g) were induced diabetes by administration of STZ (40 mg/kg) intraperitonially. Normal and diabetic rats were treated with UMB in 10 percent dimethyl sulfoxide (DMSO) for 45 days. Diabetic rats had increased plasma glucose and decreased insulin, total proteins (TP), and albumin in addition to decreased food intake and body weight. Elevation in total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), very low density lipoprotein cholesterol (VLDL-C), triglycerides (TG), free fatty acids (FFA), and phospholipids (PL), and reduction in high density lipoprotein cholesterol (HDL-C) in the plasma were observed. Liver and kidney tissues of diabetic rats had elevation in the levels of TC, TG, FFA, and PL. Treatment with UMB decreased plasma glucose and increased insulin, TP, and albumin apart from food intake and body weight. In UMB-treated diabetic rats, plasma and tissue TC, TG, PL and FFA, and plasma LDL-C, VLDL-C, and HDL-C reversed to near normal. Thus, reduction of blood glucose and lipid profiles indicates that UMB has antidiabetic and antihyperlipidemic effects in diabetic rats.

Modulation of mitogen-activated protein kinases by 6-nitro-7-hydroxycoumarin mediates apoptosis in renal carcinoma cells

6-Nitro-7-hydroxycoumarin has previously been shown to be a selective anti-proliferative agent capable of activating p38, stress-activated protein kinase (SAPK) and mitogen-activated protein (MAP) kinase in the human renal cell carcinoma cell line, A-498. Here, the role of p38 MAP kinase was further investigated in relation to its participation in 6-nitro-7-hydroxycoumarin induced apoptosis. 6-Nitro-7-hydroxycoumarin was shown to alter cell cycle progression, leading to the appearance of a sub-G(1) peak, containing hypodiploid DNA, accompanied by increases in both poly(ADP-ribose)polymerase cleavage and decreased expression of cyclin D1. Drug treatment also lead to a rise in the expression in the cyclin-dependent kinase inhibitor, p21(WAF1/CIP1), and the appearance of inter-nucleosomal DNA cleavage and morphological changes, consistent with apoptotic cell death. Using a p38 MAP kinase inhibitor, SB203580, caused expression of p21(WAF1/CIP1) to be suppressed and both cleaved poly(ADP-ribose)polymerase and the numbers of apoptotic cells were decreased. In summary, this study shows the participation of p38 MAP kinase in 6-nitro-7-hydroxycoumarin induced apoptosis of A-498 cells and suggests that targeting of p38 may represent a novel mechanism to inhibit renal cell carcinoma and that coumarin type drugs require further investigation as potential anticancer agents directed against renal cell carcinoma.

Esculetin inhibits Ras-mediated cell proliferation and attenuates vascular restenosis following angioplasty in rats

The proliferation of vascular smooth muscle cells (VSMCs) induced by injury to the intima of arteries is an important etiologic factor in vascular proliferative disorders such as atherosclerosis and restenosis. Esculetin, derived from the Chinese herb Artemisia scoparia, is well known as a lipoxygenase inhibitor. We have investigated the inhibitory effects of esculetin on VSMC proliferation and intimal hyperplasia by balloon angioplasty in the rat. We determined, using [3H]thymidine incorporation and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, that esculetin inhibited the proliferation of VSMCs via a lipoxygenase-independent pathway. Three predominant signaling pathways were identified to be inhibited by esculetin: (a) the activation of p42/44 mitogen-activated protein kinase (MAPK) and the downstream effectors of c-fos and c-jun immediate early genes by means of western and reverse transcription-polymerase chain reaction (RT-PCR) analyses; (b) the activation of nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1), using the electrophoretic mobility shift assay; and (c) the activation of phosphoinositide 3-kinase (PI 3-kinase) and cell cycle progression, by western blot analysis and flow cytometric detection. Furthermore, esculetin also profoundly inhibited Ras activation, a shared upstream event of the above signaling cascades. In vascular injury studies, intraperitoneal administration of esculetin significantly suppressed intimal hyperplasia induced by balloon angioplasty. We conclude that esculetin blocks cell proliferation via the inhibition of an upstream effector of Ras and downstream events including p42/44 MAPK activation, PI 3-kinase activation, immediate early gene expression, as well as NF-kappaB and AP-1 activation. It also inhibits intimal hyperplasia after balloon vascular injury in the rat, indicating the therapeutic potential for treating restenosis after arterial injury.

Ostruthin: an antimycobacterial coumarin from the roots of Peucedanum ostruthium

Following a bioassay-guided fractionation, ostruthin (6-geranyl-7-hydroxycoumarin) was isolated from the roots of Peucedanum ostruthium Koch (Apiaceae) as a compound with pronounced in vitro activity against several species of rapidly growing Mycobacteria, namely Mycobacterium abscesus, M. aurum, M. fortuitum, M. phlei and M. smegmatis. Minimum inhibitory concentrations (MIC) ranged between 3.4 to 107.4 microM and were comparable to those of ethambutol and isoniazid. Imperatorin (8-isopent-2-enyloxy-6,7-furanocoumarin) showed no activity at concentrations up to 1.9 mM. Umbelliferone (7-hydroxycoumarin) was only weakly active (MIC = 0.79 mM).

Evaluation of butylated hydroxyanisole, myo-inositol, curcumin, esculetin, resveratrol and lycopene as inhibitors of benzo[a]pyrene plus 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced lung tumorigenesis in A/J mice

The potential activities of butylated hydroxyanisole (BHA), myo-inositol, curcumin, esculetin, resveratrol and lycopene-enriched tomato oleoresin (LTO) as chemopreventive agents against lung tumor induction in A/J mice by the tobacco smoke carcinogens benzo[a]pyrene (BaP) and 4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) were evaluated. Groups of 20 A/J mice were treated weekly by gavage with a mixture of BaP and NNK (3 micromol each) for 8 weeks, then sacrificed 26 weeks after the first carcinogen treatment. Mice treated with BHA (20 or 40 micromol) by gavage 2 h before each dose of BaP and NNK had significantly reduced lung tumor multiplicity. Treatment with BHA (20 or 40 micromol) by gavage weekly or with dietary BHA (2000 ppm), curcumin (2000 ppm) or resveratrol (500 ppm) from 1 week after carcinogen treatment until termination had no effect on lung tumor multiplicity. Treatment with dietary myo-inositol (30,000 ppm) or esculetin (2000 ppm) from 1 week after carcinogen treatment until termination significantly reduced lung tumor multiplicity, with the effect of myo-inositol being significantly greater than that of esculetin. Treatment with dietary LTO (167, 1667 or 8333 ppm) from 1 week before carcinogen treatment until termination had no effect on lung tumor multiplicity. The results of this study demonstrate that BHA is an effective inhibitor of BaP plus NNK-induced lung tumorigenesis in A/J mice when administered during the period of carcinogen treatment and that, among the compounds tested, myo-inositol is most effective after carcinogen treatment.

Inhibitory effects of nabumetone, a cyclooxygenase-2 inhibitor, and esculetin, a lipoxygenase inhibitor, on N-methyl-N-nitrosourea-induced mammary carcinogenesis in rats

We investigated the modifying effects of nabumetone, a relatively selective cyclooxygenase-2 inhibitor, and esculetin, a lipoxygenase inhibitor, on N-methyl-N-nitrosourea(MNU)-induced mammary carcinogenesis in female Sprague-Dawley rats. A total of 124 rats, 6 weeks old, were divided into 6 groups. At 50 days of age, groups 1, 2, and 3 were treated with MNU (50 mg/kg body weight) by subcutaneous injection. From the age of 8 weeks, groups 2 and 4 were given 0.03% nabumetone in the diet and groups 3 and 5 were given 0.03% esculetin in the diet. All rats were necropsied at the termination (25 weeks after the start of experiment). The incidence and multiplicity of neoplasms in group 2 were significantly smaller than those in group 1 (P < 0.005 and P < 0.001, respectively). The incidence of neoplasms in group 3 was also significantly smaller than that in group 1 (P < 0.05). These results indicate that the intake of nabumetone or esculetin during the time corresponding to the post initiation phase has a chemopreventive effect on MNU-induced mammary carcinogenesis in rats.

Esculetin prevents liver damage induced by paracetamol and CCL4

Esculetin, a phenolic compound found in Cichorium intybus and Bougainvllra spectabillis was investigated for its possible protective effect against paracetamol and CCl4-induced hepatic damage. Paracetamol produced 100% mortality at the dose of 1 g kg-1 in mice while pre-treatment of animals with esculetin (6 mg kg-1) reduced the death rate to 40%. Oral administration of paracetamol (640 mg kg-1) produced liver damage in rats as manifested by the rise in serum enzyme levels of alkaline phosphatase (ALP) and aminotransferases (AST and ALT). Pre-treatment of rats with esculetin (6 mg kg-1) prevented the paracetamol-induced rise in serum enzymes. The hepatotoxic dose of CCl4 (1.5 ml kg-1; orally) also raised serum ALP, AST and ALT levels. The same dose of esculetin (6 mg kg-1) was able to prevent the CCl4-induced rise in serum enzymes. Esculetin also prevented CCl4-induced prolongation in pentobarbital sleeping time confirming hepatoprotectivity. These results indicate that esculetin possesses anti-hepatotoxic activity and the presence of this compound in Cichorium intybus and Bougainvllra spectabillis may explain the folkloric use of these plants in liver damage.

Auraptene, a citrus coumarin, inhibits 12-O-tetradecanoylphorbol-13-acetate-induced tumor promotion in ICR mouse skin, possibly through suppression of superoxide generation in leukocytes

Coumarin-related compounds, auraptene and umbelliferone, have been isolated from the cold-pressed oil of natsumikan (Citrus natsudaidai HAYATA), and tested as inhibitors of tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced Epstein-Barr virus activation in Raji cells. The 50% inhibitory concentration (IC50) of auraptene (18 microM) was almost equal to that of genistein. Umbelliferone, which lacks a geranyloxyl group present in auraptene, was less active (IC50 = 450 microM). In a two-stage carcinogenesis experiment with 7,12-dimethylbenz[a] anthracene (topical application at 0.19 mumol) and TPA (topical application at 1.6 nmol) in ICR mouse skin, topical application of auraptene (at 160 nmol) significantly reduced tumor incidence and the numbers of tumors per mouse by 27% (P < 0.01) and 23% (P < 0.05), respectively. Auraptene at a concentration of 50 microM markedly suppressed superoxide (O2-) generation induced by 100 microM TPA in differentiated human promyelocytic HL-60 cells. Having no O2(-)-scavenging potential, auraptene may inhibit the multicomponent NADPH oxidase system. Inhibition of intracellular hydroperoxide formation in differentiated HL-60 cells by auraptene was also confirmed by flow-cytometric analysis using 2',7'-dichlorofluorescein diacetate as a fluorescence probe. Quantitative analyses using high-performance liquid chromatography showed the occurrence of auraptene not only in both the peels and sarcocarps of natsumikan, but also in those of hassaku orange (C. hassaku) and grapefruit (C. paradisi), and even in their bottled fresh juice form. These results indicate that auraptene is a chemopreventer of skin tumorigenesis, and implies that suppression of leukocyte activation might be the mechanism through which it inhibits tumor promotion.

Antitumour activity of coumarin and 7-hydroxycoumarin against 7,12-dimethylbenz[a]anthracene-induced rat mammary carcinomas

Female SD rats with established 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumours were treated with coumarin (20 mg/kg body weight; six times per week) or its metabolite 7-hydroxycoumarin (20 mg/kg) for 4 weeks. The anti-oestrogen tamoxifen (8.8 mg/kg) served as the reference drug. The inhibitory effect of coumarin was similar to that of tamoxifen [mean change of tumour area: 428% (coumarin) compared to 528% (tamoxifen); control 822%]. The strongest inhibition was observed with 7-hydroxycoumarin (248%); the difference compared to the control was significant (P < 0.01). Neither coumarin nor 7-hydroxycoumarin reduced the number of tumours appearing during treatment as tamoxifen did. However, the size of the tumours treated with coumarin or its metabolite was generally much smaller than those in the tamoxifen group or in the control group. From the data obtained it appears that coumarin and 7-hydroxycoumarin inhibit the growth of tumours that have reached a certain size but do not prevent the formation of tumours after exposure to the carcinogen.

An updated review of the clinical development of coumarin (1,2-benzopyrone) and 7-hydroxycoumarin

Several authors have demonstrated that coumarin (1,2-benzopyrone) in combination with cimetidine can produce objective antitumor responses in some patients with advanced renal cell carcinoma. The purpose of this report is to review the clinical development of coumarin, with or without cimetidine, with special reference to renal cell carcinoma (RCC). Previously unpublished data concerning the survival of a population of patients with RCC, who were treated on a phase I trial of coumarin and cimetidine, are presented. The rationale and study design of an active randomized, double-blinded, placebo-controlled trial of coumarin for RCC are discussed. A progress report is given for an ongoing phase I trial of oral 7-hydroxycoumarin, the major human metabolite of coumarin.

Coumarin and 7-hydroxycoumarin treatment of canine obstructive lymphoedema

1. Canine obstructive lymphoedema was created in one hind leg of 30 dogs by irradiation of the groin and surgical removal of surviving lymph glands and lymphatics. The opposite leg served as a control. Once the oedema had stabilized, groups of 10 dogs were treated orally with 12.5 mg day-1 kg-1 for 8 months with either one of the benzopyrones coumarin (2H-1-benzopyran-2-one) and 7-hydroxycoumarin (7-hydroxy-2H-1-benzopyran-2-one), or placebo. 2. The two benzopyrones significantly (P less than 0.01) but gradually reduced the oedema by 20-30% over 8 months, as judged by circumferential measurements of the oedematous and control limbs. There was no change with the placebo. 3. In the oedematous fluids (lymph and interstitial fluid), benzopyrone treatment reduced the protein content and increased acid and neutral proteinase activity compared with the control limbs, while the levels of the proteinase inhibitor alpha 2-macroglobulin remained unchanged. Furthermore, these active drugs reduced the excess water content, thickness and hydroxyproline content of skin biopsies from oedematous limbs compared with those from control limbs. No changes were observed for the placebo group. 4. These biochemical changes suggest that benzopyrones can reduce the excess proteinaceous fluid in lymphoedema by increasing the levels of proteinase activity relative to the number of proteinase inhibitors. As a secondary event the amount of fibrosis in the skin is also reduced, presumably by an increase in collagenase activity from the mononuclear phagocytes. 5. These results support the hypothesis that benzopyrones activate the production of proteinases by mononuclear phagocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-inflammatory activity of benzopyrones that are inhibitors of cyclo- and lipo-oxygenase

The anti-inflammatory activity of three benzo-pyrones with prevalent lipooxigenase-inhibitory activity was studied using the Croton oil ear test in mice, in comparison with nordihydroguaieretic acid (NDGA) and indomethacin. Kaempferol, quercetin and NDGA possess a strong and prolonged anti-inflammatory effect, whereas the action of indomethacin appears relevant, but not long-lasting. In contrast the anti-inflammatory activity of esculetin is rather weak, but persistent.

Anthelmintics for cattle

A number of anthelmintics are available for the control of gastrointestinal nematodes in cattle. In North America, O. ostertagi, Cooperia spp., lung worm, and F. hepatica probably cause the greatest losses in production. The older anthelmintics are often deficient in their action against some of these parasites. Recently, the Paratect morantel tartrate slow-release bolus has provided a mechanism for the prevention of infections with gastrointestinal nematodes and lung worm, to some extent, and this has been shown to produce considerable economic benefits. Fenbendazole removes arrested O. ostertagi larvae; thus, its availability is an important step in the prevention of type-2 ostertagiasis. It also has a very broad spectrum of activity that includes most other nematodes and tapeworms and is a very safe anthelmintic. Ivermectin is highly effective against almost all cattle nematodes and also has great value for the control of arthropod ectoparasites. In addition, it and levamisole are the only anti-nematode drugs that can be administered to cattle by injection. Clorsulon is a new, safe anthelmintic that provides good control of liver fluke and, thus, fills a gap in the control of helminths of cattle in North America. The efficient use of anthelmintics in association with management based on a knowledge of parasite epidemiology can ensure that cattle do not rapidly become re-infected. In this way, the benefits from the use of anthelmintics can be very considerable and far greater than the costs of control.