Emodin (3-methyl-1,6,8-trihydroxyanthraquinone) inhibits TNF-induced NF-kappaB activation, IkappaB degradation, and expression of cell surface adhesion proteins in human vascular endothelial cells

Emodin ameliorates lipopolysaccharide-induced mastitis in mice by inhibiting activation of NF-κB and MAPKs signal pathways

Emodin is an anthraquinone derivative from the Chinese herb Radix et Rhizoma Rhei. It has been reported that emodin possesses a number of biological properties, such as anti-inflammatory, anti-virus, anti-bacteria, anti-tumor, and immunosuppressive properties. However, the effect of emodin on mastitis is not yet known. The aim of this study was to investigate whether emodin has protective effect against lipopolysaccharide (LPS)-induced mastitis in a mouse model. The mouse model of mastitis was induced by injection of LPS through the duct of mammary gland. Emodin was administered intraperitoneally with the dose of 1, 2, and 4 mg/kg respectively 1h before and 12h after induction of LPS. Emodin significantly reduced infiltration of neutrophilic granulocyte, activation of myeloperoxidase (MPO), concentration of tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6), mRNA expression levels of TNF-α, IL-1β and IL-6, which were increased in LPS-induced mouse mastitis. In addition, emodin influenced nuclear factor kappa-B signal transduction pathway by inhibiting activation of nuclear transcription factor-kappaB (NF-κB) p65 and degradation inhibitor of NF-κB α (IκBα), and emodin also influenced mitogen activated protein kinases signal transduction pathway by depression activation of p38, extracellular signal-regulated kinase (ERK), and c-jun NH2-terminal kinase (JNK). In conclusion, these results indicated that emodin could exert beneficial effects on experimental mastitis induced by LPS and may represent a novel treatment strategy for mastitis.

Emodin suppresses migration and invasion through the modulation of CXCR4 expression in an orthotopic model of human hepatocellular carcinoma

Accumulating evidence(s) indicate that CXCL12-CXCR4 signaling cascade plays an important role in the process of invasion and metastasis that accounts for more than 80% of deaths in hepatocellular carcinoma (HCC) patients. Thus, identification of novel agents that can downregulate CXCR4 expression and its associated functions have a great potential in the treatment of metastatic HCC. In the present report, we investigated an anthraquinone derivative, emodin for its ability to affect CXCR4 expression as well as function in HCC cells. We observed that emodin downregulated the expression of CXCR4 in a dose-and time-dependent manner in HCC cells. Treatment with pharmacological proteasome and lysosomal inhibitors did not have substantial effect on emodin-induced decrease in CXCR4 expression. When investigated for the molecular mechanism(s), it was observed that the suppression of CXCR4 expression was due to downregulation of mRNA expression, inhibition of NF-κB activation, and abrogation of chromatin immunoprecipitation activity. Inhibition of CXCR4 expression by emodin further correlated with the suppression of CXCL12-induced migration and invasion in HCC cell lines. In addition, emodin treatment significantly suppressed metastasis to the lungs in an orthotopic HCC mice model and CXCR4 expression in tumor tissues. Overall, our results show that emodin exerts its anti-metastatic effect through the downregulation of CXCR4 expression and thus has the potential for the treatment of HCC.

Emodin regulates glucose utilization by activating AMP-activated protein kinase

AMP-activated protein kinase has been described as a key signaling protein that can regulate energy homeostasis. Here, we aimed to characterize novel AMP-activated kinase (AMPK)-activating compounds that have a much lower effective concentration than metformin. As a result, emodin, a natural anthraquinone derivative, was shown to stimulate AMPK activity in skeletal muscle and liver cells. Emodin enhanced GLUT4 translocation and [(14)C]glucose uptake into the myotube in an AMPK-dependent manner. Also, emodin inhibited glucose production by suppressing the expression of key gluconeogenic genes, such as phosphoenolpyruvate carboxykinase and glucose-6-phosphatase, in hepatocytes. Furthermore, we found that emodin can activate AMPK by inhibiting mitochondrial respiratory complex I activity, leading to increased reactive oxygen species and Ca(2+)/calmodulin-dependent protein kinase kinase activity. Finally, we confirmed that a single dose administration of emodin significantly decreased the fasting plasma glucose levels and improved glucose tolerance in C57Bl/6J mice. Increased insulin sensitivity was also confirmed after daily injection of emodin for 8 days using an insulin tolerance test and insulin-stimulated PI3K phosphorylation in wild type and high fat diet-induced diabetic mouse models. Our study suggests that emodin regulates glucose homeostasis in vivo by AMPK activation and that this may represent a novel therapeutic principle in the treatment of type 2 diabetic models.

Dietary phytochemicals as potent chemotherapeutic agents against breast cancer: Inhibition of NF-κB pathway via molecular interactions in rel homology domain of its precursor protein p105

BACKGROUND

Dietary phytochemicals consist of a wide variety of biologically active compounds that are ubiquitous in plants, many of which have been reported to have anti-tumor as well as anti-inflammatory properties.

OBJECTIVE

In the present study, we aimed to validate these findings by using docking protocols and explicate the possible mechanism of action for a dataset of nine phytochemicals namely boswellic acid, 1-caffeoylquinic acid, ellagic acid, emodin, genistein, guggulsterone, quercetin, resveratrol, and sylibinin from different plants against the nuclear factor- kappaB (NF-κB) precursor protein p105, an important transcription factor reported to be overexpressed in breast cancer.

MATERIALS AND METHODS

2-D structures of all phytochemicals were retrieved from PubChem Compound database and their subsequent conversion into 3-D structures was performed by using online software system CORINA. The X-ray crystallographic structure of the NF-κB precursor p105 was extracted from Brookhaven Protein Data Bank. Molecular docking simulation study was carried out by using AutoDock Tools 4.0.

RESULTS

Our results showed significant binding affinity of different phytochemicals with the Rel homology domain of the NF-κB precursor protein p105. Quercetin and 1-caffeoylquinic acid were found to be very effective inhibitors against target molecule as they showed binding energy of -12.11 and -11.50 Kcal/mol, respectively. The order of affinity of other ligands with p105 was found as follows: guggulsterone > sylibinin > emodin > resveratrol > genistein > boswellic acid > ellagic acid.

CONCLUSION

Our in silico study has explored the possible chemopreventive mechanism of these phytochemicals against the NF-κB precursor protein p105 and deciphered that quercetin, 1-caffeoylquinic acid and guggulsterone were the potent inhibitors against target molecule. In addition, large scale preclinical and clinical trials are needed to explore the role of these chemotherapeutic molecules against the NF-κB precursor protein p105 in cure and prevention of breast cancer.

Cell-type dependent response of melanoma cells to aloe emodin

Intrinsic characteristics of melanoma cells such as expression of inducible nitric oxide synthase (iNOS), redox status, and activity of signaling pathways involved in proliferation, differentiation and cell death define the response of the cells to the diverse treatments. In this context we compared the effectiveness of herbal antaquinone aloe emodin (AE) against mouse B16 melanoma and human A375, different in initial activity of ERK1/2, constitutive iNOS expression and basal level of reactive oxygen species (ROS). Both cell lines are sensitive to AE treatment. However, while the agent induces differentiation of B16 cells toward melanocytes, in A375 cells promoted massive apoptosis. Differentiation of B16 cells, characterized by enhanced melanin production and tyrosinase activity, was mediated by H(2)O(2) production synchronized with rapid p53 accumulation and enhanced expression of cyclins D1 and D3. Caspase mediated apoptosis triggered in A375 cells was accompanied with Bcl-2 but not iNOS down-regulation. In addition, opposite regulation of Akt-ERK1/2 axis in AE treated B16 and A375 cells correlated with different outcome of the treatment. However, AE in a dose-dependent manner rescued both B16 and A375 cells from doxorubicin- or paclitaxel-induced killing. These data indicate that caution is warranted when AE is administrated to the patients with conventional chemotherapy.

Treatment with Rhubarb Improves Brachial Artery Endothelial Function in Patients with Atherosclerosis: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Rhubarb has been used to decrease plasma cholesterol levels and reduce vascular endothelial cellular damage in recent years. However, it is not known whether reported lipid-lowering effects are associated with the improvement of endothelial function. This work aimed to elucidate the therapeutic effects of rhubarb on serum lipids and brachial artery endothelial function, as well as to investigate the relationship between them. One hundred and three patients with atherosclerosis were randomly divided into two groups: patients in the control and the trial group received a placebo and rhubarb, respectively, in addition to the 6 month baseline therapy. Serum lipids and brachial artery endothelial functions were measured in all patients before and after treatment. A total of 83 patients completed the 6-month follow-up protocol. Serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) in the trial group decreased significantly and LDL-C was significantly lower than that in the control group. Flow-mediated dilation (FMD) in the trial group was significantly higher after treatment in comparison to the baseline and to the control group. Improvement in FMD correlated with the decreased magnitude of TC and LDL-C levels. The results obtained appeared to confirm that rhubarb significantly improves endothelial function mainly due to lipid-lowering effects in patients with atherosclerosis.

Catenarin Prevents Type 1 Diabetes in Nonobese Diabetic Mice via Inhibition of Leukocyte Migration Involving the MEK6/p38 and MEK7/JNK Pathways

Inflammation contributes to leukocyte migration, termed insulitis, and β-cell loss in type 1 diabetes (T1D). Naturally occurring anthraquinones are claimed as anti-inflammatory compounds; however, their actions are not clear. This study aimed to investigate the effect and mechanism of catenarin on the inflammatory disease, T1D. Catenarin and/or its anthraquinone analogs dose-dependently suppressed C-X-C chemokine receptor type 4 (CXCR4)- and C-C chemokine receptor type 5 (CCR5)-implicated chemotaxis in leukocytes. Catenarin, the most potent anthraquinone tested in the study, prevented T1D in nonobese diabetic mice. Mechanistic study showed that catenarin did not act on the expression of CCR5 and CXCR4. On the contrary, catenarin inhibited CCR5- and CXCR4-mediated chemotaxis via the reduction of the phosphorylation of mitogen-activated protein kinases (p38 and JNK) and their upstream kinases (MKK6 and MKK7), and calcium mobilization. Overall, the data demonstrate the preventive effect and molecular mechanism of action of catenarin on T1D, suggesting its novel use as a prophylactic agent in T1D.

Emodin inhibits invasion and migration of prostate and lung cancer cells by downregulating the expression of chemokine receptor CXCR4

Emodin (ED), an anthraquinone derivative, has been found to inhibit proliferation, induce apoptosis, suppress angiogenesis, impede metastasis, and enhance chemotherapy. However, the detailed mechanism of ED related to the regulation of CXC chemokine receptor-4 (CXCR4) gene expression that affects cellular migration and invasion in prostate and lung cancer cells are not fully understood. Recent evidence indicates that the CXCR4/CXCL12 axis is involved in promoting invasion and metastasis in tumors. Thus, novel agents that can downregulate CXCR4 expression have therapeutic potential in repressing cancer metastasis. Among ED and its derivatives, it is found that ED downregulated the expression of both CXCR4 and HER2 without affecting cell viability in tumor cells. The suppression of CXCR4 expression by ED was found to correlate with the inhibition of CXCL12-induced migration and invasion of both DU145 and A549 cells. Besides, neither proteasome inhibition nor lysosomal stabilization had any effect on ED-induced decrease in CXCR4 expression. The basic molecular mechanisms unveiled that the downregulation of CXCR4 was at the transcriptional level, as indicated by downregulation of mRNA expression and suppression of NF-κB activation. Overall, our findings suggest that ED is a novel blocker of CXCR4 expression and, thus, has enormous potential as a powerful therapeutic agent for metastatic cancer.

Anti-inflammatory effect of the ethanolic extract from Bowdichia virgilioides H.B.K stem bark

Bowdichia virgilioides H.B.K stem bark (Fabaceae), locally known as "sucupira-preta", is a reputed folk-remedy to treat some inflammatory disorders. To validate its traditional claim, the ethanolic extract from B. virgilioides was evaluated in several animal models of inflammation and nociception. The extract at oral doses of 100 to 1000 mg/kg body weight caused a significant inhibition of carrageenan-induced hind paw oedema, suppression of exudate volume and leukocyte immigration in rat pleurisy induced by carrageenan, and reduction of granuloma weights in the model of subcutaneous granulomas promoted by cotton pellets. In addition, the plant extract significantly inhibited the vascular permeability increase induced by intraperitoneal acetic acid. It also showed marked antinociceptive effect in acetic acid-induced writhing test and in the second phase of formalin test in mice. These findings evidence the anti-inflammatory potential of Bowdichia virgilioides bark and supports its traditional use in inflammatory conditions.

Anti-inflammatory activities of Reynoutria elliptica through suppression of mitogen-activated protein kinases and nuclear factor-κB activation pathways

Reynoutria elliptica has been used in traditional Korean medicine to promote blood circulation, relieve pain, increase dieresis, and alleviate respiratory problems, through as yet undefined mechanisms. We set out to determine whether the anti-inflammatory effects of this plant are linked with its ability to suppress mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB) activation in lipopolysaccharide (LPS)-activated RAW 264.7 cells. We found for the first time that the hexane fraction of Reynoutria elliptica (HRE) significantly inhibited LPS-stimulated NO and PGE2 synthesis. This is due to the diminishing of the mRNA and protein expression of iNOS and COX-2, respectively. HRE also suppressed LPS-stimulated TNF-α secretion in a dose-dependent manner, which might be due to the suppression of LPS-induced MAPKs and NF-κB activation. Moreover, our HPLC data demonstrated that the major components of the HRE were bioactive compounds such as emodin-6-Glc, emodin, and physcion. Overall, our results indicate that Reynoutria elliptica could be provided as a potential candidate for anti-inflammation treatment.

Cancer and diet: How are they related?

Extensive research in the past decade has revealed cancer to be a multigenic disease caused by perturbation of multiple cell signalling pathways and dysregulation of numerous gene products, all of which have been linked to inflammation. It is also becoming evident that various lifestyle factors, such as tobacco and alcohol use, diet, environmental pollution, radiation and infections, can cause chronic inflammation and lead to tumourigenesis. Chronic diseases caused by ongoing inflammation therefore require chronic, not acute, treatment. Nutraceuticals, compounds derived from fruits, vegetables, spices and cereals, can be used chronically. This study discusses the molecular targets of some nutraceuticals that happen to be markers of chronic inflammation and how they can prevent or treat cancer. These naturally-occurring agents in the diet have great potential as anti-cancer drugs, thus proving Hippocrates, who proclaimed 25 centuries ago, 'Let food be thy medicine and medicine be thy food'.

Analgesic and anti-inflammatory effects of ethyl acetate fraction of Polygonum cuspidatum in experimental animals

Polygonum cuspidatum (PC) has been used for the treatment of arthritis and urinary diseases in traditional medicine. Despite recent evidence that PC has anti-oxidant, anti-tumoral, and anti-inflammatory effects, analgesic and anti-inflammatory effects of PC have not been elucidated yet in vivo. Thus, in the present study, analgesic and anti-inflammatory effects of ethyl acetate extract of PC (EAPC) were investigated in vivo for the first time. Hot plate test and tail-flick test revealed that EAPC at 200 mg/kg exerts analgesic effect (p < 0.05). In contrast, EAPC did not show significant analgesic effect in acetic acid-induced writhing test. Serotonin-induced paw edema model and Freund's complete adjuvant (FCA)-induced adjuvant arthritis model were used to examine anti-inflammatory effect of EAPC in vivo. In serotonin-induced paw edema model, EAPC suppressed swelling inflammatory response within 12 min after serotonin injection, at both 100- and 200-mg/kg dose (p < 0.05). Consistently, in FCA-induced adjuvant arthritis model, FCA at 200 mg/kg significantly suppressed FCA-induced joint swelling within 3 days (p < 0.05), whereas FCA at 100 mg/kg showed the similar result within 5 days (p < 0.05). Furthermore, EAPC effectively inhibited positive responses of c-reactive protein and rheumatoid factor compared to untreated control. Taken together, our findings suggest that EAPC can be a potent candidate for rheumatoid arthritis treatment.

Suppression on metastasis by rhubarb through modulation on MMP-2 and uPA in human A549 lung adenocarcinoma: an ex vivo approach

AIM OF THE STUDY

The aim of this study is to determine and identify the possible molecular mechanisms of anti-cancer effect of rhubarb under the physiologically achievable concentrations by using an ex vivo approach.

MATERIALS AND METHODS

Rats were orally administered rhubarb decoction and then serum metabolites were extracted, prepared and characterized to assay for the following in vitro study. The MTT assay, zymography analysis, wound healing assay, RT-PCR, and Western blot analysis were used to reveal molecular events of rhubarb metabolites in this study. Experimental metastasis model was used to investigate the in vivo anti-metastatic efficacy of rhubarb.

RESULTS

Our results demonstrated that cell line mobility was strongly inhibited and the enzymatic activity of MMP-2 decreased following culture with the rhubarb serum metabolite in human lung adenocarcinoma A549 cells. Further experiments demonstrated that the downregulation of MMP-2 enzymatic activity act through both transcriptional and post-translational mechanisms. NF-κB/c-Jun and uPA were observed involving in the inhibition of MMP-2 transcription and post-translational modification, respectively, in A549 cells treated with rhubarb serum metabolite. Further animal experiments demonstrated a significant reduction in lung metastatic colonies in rhubarb-treated mice, suggesting that rhubarb contain enriched active components that block cancer metastasis.

CONCLUSIONS

Our studies, both in vitro and in vivo, clearly demonstrated the anti-tumor effect of rhubarb in an experimental setting of achievable physiological concentrations and also provide possible molecular mechanisms of anti-metastatic mechanisms by rhubarb treatment.

Regulation of survival, proliferation, invasion, angiogenesis, and metastasis of tumor cells through modulation of inflammatory pathways by nutraceuticals

Almost 25 centuries ago, Hippocrates, the father of medicine, proclaimed "Let food be thy medicine and medicine be thy food." Exploring the association between diet and health continues today. For example, we now know that as many as 35% of all cancers can be prevented by dietary changes. Carcinogenesis is a multistep process involving the transformation, survival, proliferation, invasion, angiogenesis, and metastasis of the tumor and may take up to 30 years. The pathways associated with this process have been linked to chronic inflammation, a major mediator of tumor progression. The human body consists of about 13 trillion cells, almost all of which are turned over within 100 days, indicating that 70,000 cells undergo apoptosis every minute. Thus, apoptosis/cell death is a normal physiological process, and it is rare that a lack of apoptosis kills the patient. Almost 90% of all deaths due to cancer are linked to metastasis of the tumor. How our diet can prevent cancer is the focus of this review. Specifically, we will discuss how nutraceuticals, such as allicin, apigenin, berberine, butein, caffeic acid, capsaicin, catechin gallate, celastrol, curcumin, epigallocatechin gallate, fisetin, flavopiridol, gambogic acid, genistein, plumbagin, quercetin, resveratrol, sanguinarine, silibinin, sulforaphane, taxol, gamma-tocotrienol, and zerumbone, derived from spices, legumes, fruits, nuts, and vegetables, can modulate inflammatory pathways and thus affect the survival, proliferation, invasion, angiogenesis, and metastasis of the tumor. Various cell signaling pathways that are modulated by these agents will also be discussed.

Emodin suppresses lipopolysaccharide-induced pro-inflammatory responses and NF-κB activation by disrupting lipid rafts in CD14-negative endothelial cells

BACKGROUND AND PURPOSE

Emodin [1,3,8-trihydroxy-6-methylanthraquinone] has been reported to exhibit vascular anti-inflammatory properties. However, the corresponding mechanisms are not well understood. The present study was designed to explore the molecular target(s) of emodin in modifying lipopolysaccharide (LPS)-associated signal transduction pathways in endothelial cells.

EXPERIMENTAL APPROACH

Cultured primary human umbilical vein endothelial cells (HUVECs; passages 3-5) were pre-incubated with emodin (1-50 µg·mL(-1) ). LPS-induced expression of pro-inflammatory cytokines [interleukin (IL)-1β, IL-6] and chemokines (IL-8; CCL2/MCP-1) were determined by reverse transcription-PCR and elisa. Nuclear factor-κB (NF-κB) activation, inhibitor of κB (IκB)α degradation and Toll-like receptor-4 (TLR-4) were detected by immunocytochemistry and Western blotting. Cholesterol depletion [by methyl β-cyclodextrin (MBCD), a specific cholesterol binding agent] and cholesterol replenishment were further used to investigate the roles of lipid rafts in activation of HUVECs.

KEY RESULTS

Emodin inhibited, concentration-dependently, the expression of LPS-induced pro-inflammatory cytokines (IL-1β, IL-6) and chemokines (IL-8, CCL2) and, in parallel, inhibited NF-κB activation and IκBα degradation in HUVECs. However, emodin did not inhibit the NF-κB activation and IκBα degradation induced by IL-1β. The cholesterol binding agent, MBCD, inhibited LPS-induced NF-κB activation in passaged HUVECs [which also lack the LPS receptor, membrane CD14 (mCD14)], showing that lipid rafts played a key role in LPS signalling in mCD14-negative HUVECs. Moreover, emodin disrupted the formation of lipid rafts in cell membranes by depleting cholesterol.

CONCLUSIONS AND IMPLICATIONS

Lipid rafts were crucial in facilitating inflammatory responses of mCD14-negative HUVECs to LPS. Emodin disrupted lipid rafts through depleting cholesterol and, consequently, inhibited inflammatory responses in endothelial cells.

The anthraquinone derivative emodin attenuates methamphetamine-induced hyperlocomotion and startle response in rats

Abnormal signaling mediated by epidermal growth factor (EGF) or its receptor (ErbB) is implicated in the neuropathology of schizophrenia. Previously, we found that the anthraquinone derivative emodin (3-methyl-1,6,8-trihydroxyanthraquinone) inhibits ErbB1 signaling and ameliorates behavioral deficits of the schizophrenia animal model established by EGF challenge. In the present study, we assessed acute and subchronic effects of its administration on methamphetamine-triggered behavioral hyperactivation in rats. Prior subchronic administration of emodin (50mg/kg/day, 5days, p.o.) suppressed both higher acoustic startle responses and hyperlocomotion induced by acute methamphetamine challenge. In parallel, emodin also attenuated methamphetamine-induced increases in dopamine and its metabolites and decreases in serotonin and its metabolites. Emodin administered alone also had an effect on stereotypic movement but no influence on horizontal or vertical locomotor activity. In contrast to pre-treatment, post-treatment with emodin had no effect on behavioral sensitization to methamphetamine. Administration of emodin in parallel to or following repeated methamphetamine challenge failed to affect hyperlocomotion induced by methamphetamine re-challenges. These findings suggest that emodin has unique pharmacological activity, which interferes with acute methamphetamine signaling and behavior.

Emodin enhances alveolar epithelial barrier function in rats with experimental acute pancreatitis

AIM: To investigate the effect of emodin on expression of claudin-4, claudin-5 and occludin, as well as the alveolar epithelial barrier in rats with pancreatitis induced by sodium taurocholate.

METHODS: Experimental pancreatitis was induced by retrograde injection of 5% sodium taurocholate into the biliopancreatic duct. Emodin was injected via the external jugular vein 3 h after induction of acute pancreatitis. Rats from sham operation group and acute pancreatitis group were injected with normal saline (an equivalent volume as emodin) at the same time point. Samples of lung and serum were obtained 6 h after drug administration. Pulmonary morphology was examined with HE staining. Pulmonary edema was estimated by measuring water content in lung tissue samples. Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) level were measured by enzyme-linked immunospecific assay. Serum amylase and pulmonary myeloperoxidase (MPO) activity were detected by spectrophotometry. Alveolar epithelial barrier was assessed by pulmonary dye extravasation. Expression of claudin-4, claudin-5 and occludin in lung tissue samples was examined by immunohistology, quantitative real-time reverse transcription polymerase chain reaction and Western blotting analysis, respectively.

RESULTS: Pancreatitis-associated lung injury was characterized by pulmonary edema, leukocyte infiltration, alveolar collapse, and elevated serum amylase level. The pulmonary damage, pulmonary pathological scores, serum amylase and MPO activity, TNF-α and IL-6 levels, and wet/dry ratio were decreased in rats after treatment with emodin. Immunostaining of claudin-4, claudin-5 and occludin was detected in lung tissue samples from rats in sham operation group, which was distributed in alveolar epithelium, vascular endothelium, and bronchial epithelium, respectively. The mRNA and protein expression levels of claudin-4, claudin-5 and occludin in lung tissue samples were markedly decreased, the expression level of claudin-4, claudin-5 and occluding was increased, and the pulmonary dye extravasation was reduced in lung tissue samples from rats with acute pancreatitis after treatment with emodin.

CONCLUSION: Emodin attenuates pulmonary edema and inflammation, enhances alveolar epithelial barrier function, and promotes expression of claudin-4, claudin-5 and occludin in lung tissue samples from rats with acute pancreatitis.

S-allyl-L-cysteine sulfoxide inhibits tumor necrosis factor-alpha induced monocyte adhesion and intercellular cell adhesion molecule-1 expression in human umbilical vein endothelial cells

Garlic and its water-soluble allyl sulfur-containing compound, S-Allyl-L-cysteine Sulfoxide (ACSO), have shown antioxidant and anti-inflammatory activities, inhibiting the development of atherosclerosis. However, little is known about the mechanism(s) underlying the therapeutic effect of ACSO in inhibiting the formation of atherosclerostic lesion. This study aimed to investigate whether ACSO could modulate tumor necrosis factor-alpha (TNF-alpha)-induced expression of intercellular cell adhesion molecule-1, monocyte adhesion and TNF-alpha-mediated signaling in human umbilical vein endothelial cells. While TNF-alpha promoted the intercellular cell adhesion molecule-1 mRNA transcription in a dose- and time-dependent manner, ACSO treatment significantly reduced the levels of TNF-alpha-induced intercellular cell adhesion molecule-1 mRNA transcripts (P < 0.01). Furthermore, ACSO dramatically inhibited TNF-alpha triggered adhesion of THP-1 monocytes to endothelial cells and porcine coronary artery rings. Moreover, ACSO mitigated TNF-alpha induced depolarization of mitochondrial membrane potential and overproduction of superoxide anion, associated with the inhibition of NOX4, a subunit of nicotinamide adenine dinucleotide phosphate-oxidase, mRNA transcription. In addition, ACSO also inhibited TNF-alpha-induced phosphorylation of JNK, ERK1/2 and IkappaB, but not p38. Apparently, ACSO inhibited proinflammatory cytokine-induced adhesion of monocytes to endothelial cells by inhibiting the mitogen-activated protein kinase signaling and related intercellular cell adhesion molecule-1 expression, maintaining mitochondrial membrane potential, and suppressing the overproduction of superoxide anion in endothelial cells. Therefore, our findings may provide new insights into ACSO on controlling TNF-alpha-mediated inflammation and vascular disease.

Protective effects of emodin combined with danshensu on experimental severe acute pancreatitis

OBJECTIVE AND DESIGN

In the present experiment, we aimed to determine the feasibility and curative effects of emodin combined with danshensu on experimental severe acute pancreatitis (SAP) and the mutual benefit of this synergistic strategy by a prospective animal study.

MATERIAL

Eighty Wistar rats were randomly divided into four groups (n = 20).

TREATMENT

SAP was elicited by a retrograde infusion of 5.0% sodium taurocholate into the pancreatic main duct. SAP rats in each group received no further intervention, emodin alone, danshensu (DSS) alone, and emodin combined with DSS (EDSS), respectively.

METHODS

48 h after SAP induction, all surviving animals were sacrificed to collect blood and tissue samples for the following measurements: serum levels of amylase, tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), endotoxin and D-lactate. Pancreatic levels of TNF-alpha, IL-1beta, maleic dialdehyde (MDA), myeloperoxidase (MPO) activity, nuclear factor-kappaappaB (NF-kappaB) activation as well as wet-dry weight ratio were also evaluated. Ascitic fluid was quantified and the severity of pancreatic damage was analyzed by pathological grading and scoring.

RESULTS

Compared with the SAP group, the emodin, DSS and EDSS groups had significant differences in every index. Furthermore, EDSS obviously improved all the parameters mentioned above so as to counteract inflammatory response and oxidative stress, as well as most effectively abating pancreatic and intestinal barrier injury.

CONCLUSIONS

EDSS exerted protective effects on SAP rats and remarkably alleviated the severity of experimental SAP. Mechanisms that might account for the beneficial effects include protecting the intestinal barrier, inhibiting over-inflammatory reaction and abating oxidative stress. The combined strategy proved to be more effective than either emodin or DSS alone and may cause synergistic effects in combination in the early stage of SAP. Broad potential for future clinical practice is foreseeable.

Emodin suppresses cell proliferation and fibronectin expression via p38MAPK pathway in rat mesangial cells cultured under high glucose

Our previous findings demonstrated that emodin could improve the renal function in rats with diabetic nephropathy, but little is known about its molecular mechanisms. In this study, we investigated the effects of emodin on high glucose (HG)-induced cell proliferation and fibronectin (FN) protein expression in rat mesangial cells, and explored the possible mechanism. Cell proliferation and cell cycle were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry assay, respectively. The protein levels of FN, p-p38MAPK, t-p38MAPK, p-CREB, PPARgamma, and CTGF in rat mesangial cells were detected by Western blot. Our results demonstrated that emodin significantly suppressed HG-induced cell proliferation and arrested cell cycle progress. Protein expression of FN, phospho-p38MAPK, phospho-CREB and CTGF was markedly reduced, and PPARgamma protein level was significantly increased after emodin treatment. In conclusion, emodin suppressed HG-induced cell proliferation and FN expression in rat mesangial cells through inhibiting the p38MAPK pathway involved CREB, PPAPgamma and CTGF, suggesting a potential role of emodin in the treatment of diabetic nephropathy.

Emodin has cytotoxic and protective effects in rat C6 glioma cells: roles of Mdr1a and nuclear factor kappaB in cell survival

1,3,8-Trihydroxy-6-methylanthaquinone (emodin) is recognized as an antiproliferative compound. In the present study, however, we show that emodin has both toxic and survival effects in glioma cells and that the survival effects involve Mdr1a. Emodin inhibited the proliferation and induced apoptosis of C6 cells in a 12-h treatment, but C6 cells survived a 72-h drug treatment, indicating resistance to emodin. Emodin-induced apoptosis was reduced by inhibition of the expression and activation of apoptosis-associated proteins including p53, Bax, Bcl-2, Fas, and caspase-3. C6 cells could express antioxidant proteins (superoxide dismutase and catalase) to decrease reactive oxygen species-induced cytotoxicity of emodin and overexpress multidrug resistance genes (Mdr1a, MRP2, MRP3, and MRP6) to decrease the intracellular accumulation of emodin. Electrophoretic mobility shift analysis showed that emodin decreased nuclear factor kappaB (NF-kappaB) expression in 24 h of treatment, but in 48 h, emodin increased NF-kappaB activity. A confocal microscope showed that emodin induced NF-kappaB translocation from cytoplasm to nuclei. C6 cells would activate the mitogen-activated protein kinase survival pathway and express the DNA repair gene (MGMT) and associated proteins (PARP and XRCC1) to recover the cell activity. C6 cells also expressed GRP78 to decrease emodin-induced endoplasmic reticulum (ER) stress that would cause apoptosis in C6 cells, and GRP78 inhibited the expression of GADD153 to enhance the expression of Bcl-2 that could balance the ER- and mitochondria-induced apoptosis of C6 cells.

Effects of emodin on the gene expression profiling of human breast carcinoma cells

BACKGROUND

The mechanism of emodin-mediated cell apoptosis has been investigated extensively in many types of human cancer cells. Our previous study demonstrated that emodin induced apoptosis through the decrease of Bcl-2/Bax ratio and the increase of cytoplasm cytochrome c concentration in human breast cancer BCap-37 cells. However, emodin's reaction to breast cancer cells remains elusive.

MATERIALS AND METHODS

An apoptosis-associated cDNA microarray comprised of 458 known genes, namely, death receptors, calpains, death kinases, granzymes, DNA fragmentation proteins, caspases and Bcl-2 family, was used to determine the impact of emodin in breast cancer BCap-37 cells. Furthermore, the candidate emodin target genes were further evaluated via real-time quantitative PCR and Western blot analysis.

RESULTS

We found that gene expression profiling in human breast cancer BCap-37 cells was altered when exposed to emodin. Thirty of the unique genes that were either induced or repressed in response to emodin-induced apoptosis were also identified. A follow-up study characterized p53, emodin-induced gene, IGF-2, and emodin-repressed gene, and the downstream proteins were also seen as possible molecular targets of emodin.

CONCLUSION

Data from this study provide novel evidence that emodin induces gene expression profiling changes, but has no effects on caspases. In addition, the p53 pathway may cooperate with the IGF-2 pathway, resulting in an emodin-induced apoptosis through disruption of the mitochondrial signaling pathway in BCap-37 cells.

Ginsenoside Rb1 inhibits tumor necrosis factor-alpha-induced vascular cell adhesion molecule-1 expression in human endothelial cells

We investigated whether ginsenoside Rb1 (Rb1) could block tumor necrosis factor-alpha (TNF-alpha)-induced over-expression of vascular cell adhesion molecule-1 (VCAM-1) in human umbilical vein endothelial cells (HUVECs) and human lung microvascular endothelial cells (HMVECs-L). Cells were treated with various concentrations of TNF-alpha with or without Rb1 pre-treatment for 16 h. The mRNA and protein levels of VCAM-1 were determined with real-time polymerase chain reaction (PCR) and flow cytometry, respectively. Human monocytic THP-1 cells labeled with fluorescent dye (Calcein-AM) was used for the adhesion assay on HUVEC monolayers. Dihydroethidium (DHE) was used to demonstrate in situ levels of superoxide production. JC-1 dye was used to measure changes in mitochondrial membrane potential. Activation of mitogen-activated protein kinase (MAPK) and nuclear factor-kappaB (NF-kappaB) was determined by Bio-Plex immunoassay. TNF-alpha treatment significantly increased the mRNA and protein levels of VCAM-1 in HUVECs in a dose dependent manner. Rb1 pre-treatment effectively blocked the TNF-alpha-induced expression of VCAM-1 mRNA or protein by 80% and 43%, respectively (p<0.01). THP-1 adhesion was also blocked. Furthermore, Rb1 reduced the TNF-alpha-induced increase of superoxide anion production by 41% and inhibited the TNF-alpha-induced decrease of mitochondrial membrane potential by 44% in HUVECs. Rb1 also effectively blocked TNF-alpha-induced activation of p38, c-Jun N-terminal protein kinase, extracellular signal-regulated kinase 1/2 and IkappaBalpha. In conclusion, Rb1 effectively blocked the TNF-alpha-induced over-expression of VCAM-1, increased THP-1 adhesion and over-production of superoxide anion. Furthermore, Rb1 inhibited TNF-alpha-induced MAPKs and NF-kappaB activation. These data suggested that Rb1 might have potential therapeutic effects in controlling inflammation in vascular diseases.

Emodin inhibits TNF-alpha-induced human aortic smooth-muscle cell proliferation via caspase- and mitochondrial-dependent apoptosis

Vascular smooth-muscle cell (VSMC) proliferation plays a vital role in hypertension, atherosclerosis and restenosis. It has been reported that emodin, an active component extracted from rhubarb, can stop the growth of cancer cells; however, it is not known if emodin exerts similar anti-atherogenic effects in TNF-alpha treated human aortic smooth-muscle cells (HASMC). In this study, emodin treatment showed potent inhibitory effects in TNF-alpha-induced HASMC proliferation that were associated with induced apoptosis, including the cleavage of poly ADP-ribose polymerase (PARP). Moreover, inhibitors of caspase-3, -8 and -9 (Ac-DEVD-CHO, Z-IETD-FMK and Z-LEHD-FMK) efficiently blocked emodin-induced apoptosis in TNF-alpha treated HASMC. Therefore, emodin-induced cell death occurred via caspase-dependent apoptosis. Emodin treatment resulted in the release of cytochrome c into cytosol and a loss of mitochondrial membrane potential (DeltaPsi(m)), as well as a decrease in the expression of an anti-apoptotic protein (Bcl-2) and an increase in the expression of an a pro-apoptotic protein (Bax). Emodin-mediated apoptosis was also blocked by a mitochondrial membrane depolarization inhibitor, which indicates that emodin-induced apoptosis occurred via a mitochondrial pathway. Taken together, the results of this study showed that emodin inhibits TNF-alpha-induced HASMC proliferation via caspase- and a mitochondrial-dependent apoptotic pathway. In addition, these results indicate that emodin has potential as an anti-atherosclerosis agent.

Exploration of Emodin to treat alpha-naphthylisothiocyanate-induced cholestatic hepatitis via anti-inflammatory pathway

Emodin, 1,3,8-trihydroxy-6-methyl-anthraquinone, is an anthraquinone derivative from the roots of Rheum officinale Baill that has been used to treat many diseases in digestive system for thousands of years. This study is to disclose the mechanism of Emodin to treat cholestatic hepatitis via anti-inflammatory pathway. Rats were divided into Emodin, ursodeoxycholic acid, Dexamethasone, model and blank control groups with treatment of respective agent after administration of alpha-naphthylisothiocyanate. At 24 h, 48 h and 72 h time points after administration, liver function, pathological changes of hepatic tissue, tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, myeloperoxidase (MPO), malondialdehyde (MDA), superoxide dismutase (SOD), cytokine-induced neutrophil chemoattractant (CINC)-1, macrophage inflammatory protein (MIP)-2, intercellular adhesion molecule (ICAM)-1, nuclear factor (NF)-kappaB and early growth response (Egr)-1, nitric oxide (NO) and inducible nitric oxide synthase (iNOS) were detected. As a result, compared to the controls, Emodin had a notable effect on rat's living condition, pathological manifestation of hepatic tissue, total bilirubin, direct bilirubin, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) (P<0.05), but had little effect on alkaline phosphatase (ALP), gamma-glutamyltransferase (GGT) and total bile acid. With Emodin intervention, levels of TNF-alpha, IL-6, MPO, MDA, CINC-1, MIP-2, ICAM-1 and translocation of NF-kappaB were remarkably decreased, and levels of NO and iNOS were markedly increased (P<0.05). Emodin had no effect on Egr-1. In conclusion, Emodin has a protective effect on hepatocytes and a restoring activity on cholestatic hepatitis by anti-inflammation. The effects are mainly due to antagonizing pro-inflammatory cytokines and mediators, inhibiting oxidative damage, improving hepatic microcirculation, reducing impairment signals, and controlling neutrophil infiltration.

The effect of emodin-assisted early enteral nutrition on severe acute pancreatitis and secondary hepatic injury

Severe acute pancreatitis (SAP) characterized by atrocious progression and numerous complications often leads to a high mortality rate due to hypermetabolism, systemic inflammatory response syndrome (SIRS), and multiple organs dysfunction syndrome (MODS). Studies have revealed that both early enteral nutrition (EEN) and emodin are potent agents in the management of SAP. However, whether the combined strategy is rational and more effective than either one alone remains unknown. In this regard, Wistar rats were treated with emodin-assisted EEN (EAEEN) through enteral nutrient tubes after induction of SAP by retrograde infusion of 5.0% sodium taurocholate into the common pancreatic duct. Serum levels of amylase, tumor necrosis factor-alpha (TNF-α), angiotensin II (AngII), maleic dialdehyde (MDA), glutamic pyruvic transaminase (ALT), glutamic oxaloacetic transaminase (AST) and C-reactive protein (CRP), intestinal secretory IgA (SIgA), pancreatic and hepatic myeloperoxidase (MPO) activity as well as plasma levels of D-lactate and endotoxin were measured. In addition, pathologic alterations of pancreas and liver were observed microscopically. We found that EAEEN could significantly ameliorate these parameters and prevent pancreas and liver from serious damage. In conclusion, Our results indicated that EAEEN could exert beneficial effects on experimental SAP and obviously abate the severity of secondary hepatic injury. The combined strategy was safe and more effective than either one alone in the acute stage of SAP. This study also provided an experimental base for the clinical treatment of SAP patients with EAEEN.

Topical anti-inflammatory activity of Polygonum cuspidatum extract in the TPA model of mouse ear inflammation

Background

This study tested the ability of a characterized extract of Polygonum cuspidatum (PCE) to inhibit mouse ear inflammation in response to topical application of 12-O-tetradecanoylphorbol-13-acetate (TPA).

Methods

A 50% (wt:vol) ethanolic solution of commercial 200:1 PCE was applied to both ears of female Swiss mice (n = 8) at 0.075, 0.15, 0.3, 1.25 and 2.5 mg/ear 30 min after TPA administration (2 μg/ear). For comparison, 3 other groups were treated with TPA and either 1) the vehicle (50% ethanol) alone, 2) indomethacin (0.5 mg/ear), or 3) trans-resveratrol (0.62 mg/ear). Ear thickness was measured before TPA and at 4 and 24 h post-TPA administration to assess ear edema. Ear punch biopsies were collected at 24 h and weighed as a second index of edema. Myeloperoxidase activity was measured in each ear punch biopsy to assess neutrophil infiltration.

Results

PCE treatment at all doses significantly reduced ear edema compared to the TPA control. The PCE response was dose-dependent and 2.5 mg PCE significantly inhibited all markers of inflammation to a greater extent than indomethacin (0.5 mg). MPO activity was inhibited at PCE doses ≥ 1.25 mg/ear. Trans-resveratrol inhibited inflammation at comparable doses.

Conclusion

PCE inhibits development of edema and neutrophil infiltration in the TPA-treated mouse ear model of topical inflammation.

NF-kappaB-inhibiting naphthopyrones from the Fijian echinoderm Comanthus parvicirrus

The two naphthopyrones 6-methoxycomaparvin (1) and 6-methoxycomaparvin 5-methyl ether (2) were isolated from a bioactive methanol-soluble extract of the Fijian echinoderm Comanthus parvicirrus. Their structures were assigned on the basis of spectroscopic methods. X-ray diffraction analysis was used to confirm the structure of 1. Both compounds were tested for their potential to inhibit the activation of the transcription factor NF-kappaB, which plays an important role in cancer development and inflammation, and the mechanism of action of the two compounds was investigated. Both naphthopyrones 1 and 2 completely inhibit TNF-alpha-induced NF-kappaB activation at a concentration of 300 microM by inhibiting the enzymatic activity of the kinase IKKbeta.

Visfatin/Pre-B cell colony-enhancing factor in amniotic fluid in normal pregnancy, spontaneous labor at term, preterm labor and prelabor rupture of membranes: an association with subclinical intrauterine infection in preterm parturition

OBJECTIVE

Visfatin, a novel adipokine originally discovered as a pre-B-cell colony enhancing factor, is expressed by amniotic epithelium, cytotrophoblast, and decidua and is over-expressed when fetal membranes are exposed to mechanical stress and/or pro-inflammatory stimuli. Visfatin expression by fetal membranes is dramatically up-regulated after normal spontaneous labor. The aims of this study were to determine if visfatin is detectable in amniotic fluid (AF) and whether its concentration changes with gestational age, spontaneous labor, preterm prelabor rupture of membranes (preterm PROM) and in the presence of microbial invasion of the amniotic cavity (MIAC).

METHODS

In this cross-sectional study, visfatin concentration in AF was determined in patients in the following groups: 1) mid-trimester (n=75); 2) term not in labor (n=27); 3) term in spontaneous labor (n=51); 4) patients with preterm labor with intact membranes (PTL) without MIAC who delivered at term (n=35); 5) patients with PTL without MIAC who delivered preterm (n=52); 6) patients with PTL with MIAC (n=25); 7) women with preterm PROM without MIAC (n=26); and 8) women with preterm PROM with MIAC (n=26). Non-parametric statistics were used for analysis.

RESULTS

1) The median AF concentration of visfatin was significantly higher in patients at term than in mid-trimester; 2) Among women with PTL who delivered preterm, the median visfatin concentration was significantly higher in patients with MIAC than those without MIAC; 3) Similarly, patients with PTL and MIAC had a higher median AF visfatin concentration than those with PTL who delivered at term; 4) Among women with preterm PROM, the median AF visfatin concentration was significantly higher in patients with MIAC than those without MIAC.

CONCLUSIONS

1) Visfatin is a physiologic constituent of AF; 2) The concentration of AF visfatin increases with advancing gestational age; 3) AF visfatin concentration is elevated in patients with MIAC, regardless of the membrane status, suggesting that visfatin participates in the host response against infection.

Molecular mechanism of emodin action: transition from laxative ingredient to an antitumor agent

Anthraquinones represent a large family of compounds having diverse biological properties. Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is a naturally occurring anthraquinone present in the roots and barks of numerous plants, molds, and lichens, and an active ingredient of various Chinese herbs. Earlier studies have documented mutagenic/genotoxic effects of emodin, mainly in bacterial system. Emodin, first assigned to be a specific inhibitor of the protein tyrosine kinase p65lck, has now a number of cellular targets interacting with it. Its inhibitory effect on mammalian cell cycle modulation in specific oncogene overexpressed cells formed the basis of using this compound as an anticancer agent. Identification of apoptosis as a mechanism of elimination of cells treated with cytotoxic agents initiated new studies deciphering the mechanism of apoptosis induced by emodin. At present, its role in combination chemotherapy with standard drugs to reduce toxicity and to enhance efficacy is pursued vigorously. Its additional inhibitory effects on angiogenic and metastasis regulatory processes make emodin a sensible candidate as a specific blocker of tumor-associated events. Additionally, because of its quinone structure, emodin may interfere with electron transport process and in altering cellular redox status, which may account for its cytotoxic properties in different systems. However, there is no documentation available which reviews the biological activities of emodin, in particular, its growth inhibitory effects. This review is an attempt to analyze the biological properties of emodin, a molecule offering a broad therapeutic window, which in future may become a member of anticancer armamentarium.

Emodin-mediated protection from acute myocardial infarction via inhibition of inflammation and apoptosis in local ischemic myocardium

Acute myocardial infarction (AMI) is associated with inflammation and apoptosis. Emodin plays an anti-inflammatory role in several inflammatory diseases. Recent studies have demonstrated that emodin protects against myocardial ischemia/reperfusion injury. However, its mechanism underlying its effects remains unknown. In a murine model of AMI, based on ligation of the left coronary artery, administration of emodin reduced myocardial infarct size (MIS) in a dose-dependent manner. Emodin significantly suppressed TNF-alpha expression and NF-kappaB activation in the local myocardial infarction area. Treatment with emodin inhibited myocardial cell apoptosis by inhibiting caspase-3 activation. Therefore, these studies demonstrate that emodin protects against myocardial cell injury via suppression of local inflammation and apoptosis.

Inhibitory effects of Hu-qi-yin on the bleomycin-induced pulmonary fibrosis in rats

The currently accepted approaches to treatment of pulmonary fibrosis are based on the treatment of alveolitis and pulmonary fibrosis, however clinically available anti-inflammatory and antifibrotic agents are not often beneficial. Hu-qi-yin, one of the traditional Chinese herbal formulas, has been used for clinical therapy of pulmonary fibrosis in China. The aim of the present study is to evaluate the preventive effects of Hu-qi-yin on the bleomycin (BLM)-induced pulmonary fibrosis in rats. The degree of fibrosis was evaluated with hydroxyproline contents in serum and lung tissue 28 days post-BLM instillation. The semi-quantitative analyses of lung sections were conducted to evaluate the intensity of alveolitis and fibrosis. Furthermore, the expression of transforming growth factor-beta(1) (TGF-beta(1)) was quantitatively studied at the protein and mRNA levels by immunohistochemistry and in situ hybridization, respectively. Oral treatment with Hu-qi-yin improved the body weight loss of rats in doses of 3.8, 7.6g/kg compared with BLM-treated control group, and significantly inhibited the alveolitis and pulmonary fibrosis in a dose-dependent manner as reflected by decreases of the hydroxyproline contents of serum and lung, and amelioration of alveolitis and pulmonary fibrosis fraction 28 days after BLM administration. The one of the possible mechanisms of the protective effect of Hu-qi-yin was via reduction of the overexpression of TGF-beta(1) protein and mRNA. These results suggested a great potential that Hu-qi-yin might be effective in the treatment of pulmonary fibrosis.

Emodin Induces Growth Arrest and Death of Human Vascular Smooth Muscle Cells Through Reactive Oxygen Species and p53

Percutaneous coronary intervention is the main therapy for revascularization of occluded coronary arteries. However, a progressive artery restenosis caused by abnormal proliferation and migration of vascular smooth muscle cells (VSMC) hinders the effective treatment. In this study, we examined the effect of emodin, a natural anthraquinoid compound, on cultured VSMC. Lower doses of emodin suppressed cell proliferation and induced unscheduled DNA synthesis. Higher doses of emodin increased lumpy chromatin condensation and lysosomes in VSMC, suggesting the occurrence of apoptosis and autophagy. Emodin increased production of reactive oxygen species (ROS), which was abolished by an NADPH oxidase inhibitor diphenylene iodonium (DPI). DPI could also decrease the number of apoptosis induced by emodin, suggesting the involvement of ROS in emodin-induced apoptosis. Emodin upregulated the protein levels of p53 in a dose-dependent manner. Laser confocal microscope showed most of emodin scattering in the cytoplasms and a little within the nuclei. These findings collectively indicated that emodin induces both growth arrest and death of human VSMCs in 2 independent manners, implying it as a promising therapy for preventing restenosis.

Pre-B-cell Colony-enhancing Factor (PBEF/Visfatin) Gene Expression is Modulated by NF-κB and AP-1 in Human Amniotic Epithelial Cells

A localized intrauterine inflammatory response is often associated with the initiation of normal human parturition, whereas infection causes a similar but more florid response initiating preterm labor. Pre-B-cell colony-enhancing factor (PBEF) is expressed in the human fetal membranes and is up-regulated by labor, severe infection and inflammatory stimuli. The aim of this study was to determine the involvement of the transcription factors NF-kappaB and AP-1 in the response of PBEF to an inflammatory stimulus and compare it with IL-8. The results showed that this treatment of amniotic epithelial-like cells (WISH) and primary amniotic epithelial cells increased expression of PBEF and IL-8, but IL-8 responded 100-fold more than PBEF. IL-1beta treatment together with a panel of NF-kappaB and AP-1 inhibitors demonstrated the involvement of these transcription factors in the up-regulation of PBEF. These data show that an inflammatory stimulus in the fetal membranes inducing NF-kappaB and AP-1 would up-regulate PBEF as well as IL-8.

TNFR1-induced NF-kappaB, but not ERK, p38MAPK or JNK activation, mediates TNF-induced ICAM-1 and VCAM-1 expression on endothelial cells

Tumour necrosis factor (TNF) is a pro-inflammatory cytokine, whose primary targets include vascular endothelial cells. TNF-mediated adhesion molecule expression has been shown to play a central role in endothelial cells inflammatory responses and disorders such as atherosclerosis. However it is not fully understand how the TNF receptor subtypes, namely TNFR1 and TNFR2, regulate inflammatory responses in endothelial cells. The aim of this study was to elucidate the kinase signalling pathways that TNF receptors activate, and determine the pathways responsible for downstream expression of adhesion molecules, intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in human endothelial cells. Using human umbilical vein endothelial cells (HUVEC), we demonstrated that TNF activates a range of mitogen-activated protein kinases (MAPKs), including the extracellular-regulated kinase (ERK) pathway and the p38MAPK and c-Jun N-terminal kinase (JNK) stress kinase pathways. Human endothelial cells express both TNF receptor subtypes at low levels, however using TNFR-specific agonistic agents, we uncovered that TNF acts through its TNFR1 receptor subtype to activate NF-kappaB transcriptional pathways. Further investigation revealed that ICAM-1 and VCAM-1 mRNA and protein are induced by TNFR1 (but not TNFR2) in a wholly NF-kappaB-dependent manner. These findings reveal for the first time that TNF stimulation of adhesion molecules ICAM-1 and VCAM-1 in human endothelial cells occurs through the TNFR1 subtype and is mediated by the NF-kappaB pathway, but not the ERK, p38MAPK or JNK kinase pathways.

Anti-cancer properties of anthraquinones from rhubarb

Rhubarb has been used as a traditional Chinese medicine since ancient times and today it is still present in various herbal preparations. In this review the toxicological and anti-neoplastic potentials of the main anthraquinones from Rhubarb, Rheum palmatum, will be highlighted. It is interesting to note that although the chemical structures of various anthraquinones in this plant are similar, their bioactivities are rather different. The most abundant anthraquinone of rhubarb, emodin, was capable of inhibiting cellular proliferation, induction of apoptosis, and prevention of metastasis. These capabilities are reported to act through tyrosine kinases, phosphoinositol 3-kinase (PI3K), protein kinase C (PKC), NF-kappa B (NF-kappaB), and mitogen-activated protein kinase (MAPK) signaling cascades. Aloe-emodin is another major component in rhubarb found to have anti-tumor properties. Its anti-proliferative property has been demonstrated to be through the p53 and its downstream p21 pathway. Our recent proteomic study also suggests that the molecular targets of these two anthraquinones are different. However, both components were found to be able to potentiate the anti-proliferation of various chemotherapeutic agents. Rhein is the other major rhubarb anthraquinone, although less well studied. This compound could effectively inhibit the uptake of glucose in tumor cells, caused changes in membrane-associated functions and led to cell death. Interestingly, all three major rhubarb anthraquinones were reported to have in vitro phototoxic. This re-evaluation of an old remedy suggests that several bioactive anthraquinones of rhubarb possess promising anti-cancer properties and could have a broad therapeutic potential.

Inhibitory effect of emodin on tissue inhibitor of metalloproteinases-1 (TIMP-1) expression in rat hepatic stellate cells

Emodin inhibited expression of both transforming growth factor beta1 (TGFbeta1)- and phorbol ester (PMA)-induced tissue inhibitors of metalloproteinase-1 (TIMP-1) in an immortalized rat hepatic stellate cell line, HSC-T6, by Western blot and reverse transcription polymerase chain reaction. Reporter gene assays showed that emodin reduced both basal and PMA-induced activated protein-1 (AP-1) promoter activities. Electrophoretic mobility shift assay revealed that emodin reduced AP-1 DNA binding activities in HSC-T6 cells. AP-1 components analysis showed that emodin also attenuated JunD mRNA expression. Furthermore, emodin markedly inhibited TGFbeta1-induced p42/p44 mitogen-activated protein kinase phosphorylation but did not alter PMA induction. We conclude that emodin effectively inhibits PMA- and TGFbeta1-stimulated TIMP-1 expression in hepatic stellate cells by suppressing the AP-1 signaling pathway and extracellular signal-regulated kinase activation, respectively. These data provide new insight into the cellular and molecular mechanisms of emodin against liver fibrosis.

Emodin with PPARgamma ligand-binding activity promotes adipocyte differentiation and increases glucose uptake in 3T3-Ll cells

Emodin, one of the main active components in the root and rhizome of Rheum palmatum L, promoted the conversion of 3T3-L1 fibroblasts to adipocytes, as evidenced by increased glycerol-3-phosphate dehydrogenase (GPDH) activity and the expression of adipocyte aP2 mRNA, as well as accelerated triacylglycerol (TG) accumulation, which was associated with increased mRNA expression levels of both C/EBPalpha and PPARgamma2. By using surface plasmon resonance (SPR) experiment, it was showed that emodin exhibited a very high binding affinity to PPARgamma. In differentiated 3T3-L1 adipocytes, emodin induced a time- and dose-dependent increase in glucose uptake as well as GLUT1 and GLUT4 mRNA expression, and the rate of uptake was partly abrogated by wortmannin (phosphoinositide 3-kinase inhibitor). Meanwhile, insulin-stimulated glucose uptake was increased significantly after treatment with low doses of emodin, and the degree of potentiation was decreased thereafter in response to increasing concentrations. Furthermore, 50 microM emodin profoundly inhibited insulin-stimulated glucose uptake by 25%. These data suggest a new role for emodin as a PPARgamma agonist in 3T3-L1 cells. Besides, it is possible that emodin may also possess other properties contribute to glucose utilization in the adipocytes.

Potential synergism of natural products in the treatment of cancer

Cancer is the second leading cause of death worldwide. There is thus increased interest in alternative treatment modalities that include chemotherapy, hormonal supplements, surgery, radiation therapy, complementary or alterative medicine, used alone or in combination. Therefore patients who are subjected to combination treatments such as hormonal supplements or alternative medicine face considerable risk of drug-drug interactions. The administration of herbal drugs by patients without a physician's prior counseling is increasing globally and there is a possibility of herb-drug interactions too. Herbal drugs or extracts themselves contain a combination of active constituents, which interact within themselves and also between other prescribed pharmaceutical drugs to either enhance (synergize) or decrease (antagonize) the therapeutic effect. This review focuses on a number of reports of herb-drug interactions, their mechanism of action with a special emphasis on dietetic phytochemicals such as quercetin, genistein, curcumin and catechins. All phytochemicals tend to increase the therapeutic effect by blocking one or more targets of the signal transduction pathway, by increasing the bioavailability of the other drug or, by stabilizing the other drug in the system.

Emodin inhibits vascular endothelial growth factor-A-induced angiogenesis by blocking receptor-2 (KDR/Flk-1) phosphorylation

Emodin (1,3,8-trihydroxy-6-methylanthraquinone), an active component in the root and rhizome of Rheum palmatum, is a tyrosine kinase inhibitor with a number of biological activities, including antitumor effects. Here, we examine the effects of emodin on vascular endothelial growth factor (VEGF)-A-induced angiogenesis, both in vitro and in vivo. In vitro, emodin dose-dependently inhibits proliferation, migration into the denuded area, invasion through a layer of Matrigel and tube formation of human umbilical vein endothelial cells (HUVECs) stimulated with VEGF-A. Emodin also inhibits basic fibroblast growth factor-induced proliferation and migration of HUVECs and VEGF-A-induced tube formation of human dermal microvascular endothelial cells. Specifically, emodin induces the cell cycle arrest of HUVECs in the G0/G1 phase by suppressing cyclin D1 and E expression and retinoblastoma protein phosphorylation, and suppresses Matrigel invasion by inhibiting the basal secretion of matrix metalloproteinase-2 and VEGF-A-stimulated urokinase plasminogen activator receptor expression. Additionally, emodin effectively inhibits phosphorylation of VEGF-A receptor-2 (KDR/Flk-1) and downstream effector molecules, including focal adhesion kinase, extracellular signal-regulated kinase 1/2, p38 mitogen-activated protein kinase, Akt and endothelial nitric oxide synthase. In vivo, emodin strongly suppresses neovessel formation in the chorioallantoic membrane of chick and VEGF-A-induced angiogenesis of the Matrigel plug in mice. Our data collectively demonstrate that emodin effectively inhibits VEGF-A-induced angiogenesis in vitro and in vivo. Moreover, inhibition of phosphorylation of KDR/Flk-1 and downstream effector molecules is a possible underlying mechanism of the anti-angiogenic activity of emodin. Based on these data, we propose that an interaction of emodin with KDR/Flk-1 may be involved in the inhibitory function of emodin toward VEGF-A-induced angiogenesis in vitro and responsible for its potent anti-angiogenic in vivo.