The protective effect of eupatilin on indomethacin-induced cell damage in cultured feline ileal smooth muscle cells: involvement of HO-1 and ERK

The Effect of CKD-495, Eupacidin, and Their Marker Compounds on Altered Permeability in a Postoperative Ileus Animal Model

Background and Objectives: Postoperative ileus (POI) is a delay in gastrointestinal transit following surgery that leads to various complications. There is limited understanding of its effective treatment options. CKD-495 and eupacidin are natural products licensed for treating mucosal lesions in acute and chronic gastritis; however, little is known about their effects on intestinal permeability. This study evaluated the effects of CKD-495, eupacidin, and its components (eupatilin and cinnamic acid) on intestinal permeability in an animal model of POI. Materials and Methods: Guinea pigs underwent surgical procedures and were randomly assigned to different treatment groups. Drugs were administered orally prior to surgery. Intestinal permeability, leukocyte count, and the expression of calprotectin and tight junction proteins were measured in the harvested ileum tissue. Results: The intestinal permeability and leukocyte count were higher in the POI group than in the control group. The pre-administration of CKD-495, cinnamic acid, eupacidin, and eupatilin effectively prevented these changes in the POI model. No significant differences were observed in the expression of tight junction proteins. Conclusions: CKD-495, cinnamic acid, eupacidin, and eupatilin exerted protective effects against increased intestinal permeability and inflammation in an animal model of POI. These natural products have potential as therapeutic options for the treatment of POI.

Anti-Inflammatory Effect of Chestnut Honey and Cabbage Mixtures Alleviates Gastric Mucosal Damage

Gastritis, one of the most common gastrointestinal disorders, damages the stomach lining as it causes a disproportion between the protective and ruinous factors of the gastric system. Cabbage (CB) is widely used to treat gastric lesions but requires the addition of natural sweeteners to counteract its distinct bitter taste. Therefore, this study sought to determine whether the combination of chestnut honey (CH)-which is known for its dark brown color and high kynurenic acid (KA) content-or KA-increased CH (KACH) with CB (CH + CB or KACH + CB) exerts synergistic effects for improving both taste and efficacy. Before confirming the gastroprotective effects in indomethacin (INDO)-induced rats, the anti-inflammatory activities of CH + CB and KACH + CB were assessed in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. As a result, treatment with either CH + CB or KACH + CB downregulated pro-inflammatory cytokine levels in LPS-stimulated RAW 264.7 macrophages by regulating the translocation of nuclear factor kappa B. Furthermore, both CH + CB and KACH + CB not only enhanced the levels of antioxidant enzymes but also triggered the activation of nuclear factor erythroid-related factor 2. Based on these effects, CH + CB or KACH + CB effectively protected the gastric mucosa in INDO-induced rats. Therefore, this study suggests that CH + CB and KACH + CB exert stronger gastroprotective effects when used together.

Natural Antioxidant and Anti-Inflammatory Compounds in Foodstuff or Medicinal Herbs Inducing Heme Oxygenase-1 Expression

Heme oxygenase-1 (HO-1) is an inducible antioxidant enzyme that catalyzes heme group degradation. Decreased level of HO-1 is correlated with disease progression, and HO-1 induction suppresses development of metabolic and neurological disorders. Natural compounds with antioxidant activities have emerged as a rich source of HO-1 inducers with marginal toxicity. Here we discuss the therapeutic role of HO-1 in obesity, hypertension, atherosclerosis, Parkinson's disease and hepatic fibrosis, and present important signaling pathway components that lead to HO-1 expression. We provide an updated, comprehensive list of natural HO-1 inducers in foodstuff and medicinal herbs categorized by their chemical structures. Based on the continued research in HO-1 signaling pathways and rapid development of their natural inducers, HO-1 may serve as a preventive and therapeutic target for metabolic and neurological disorders.

Eupatilin Promotes Cell Death by Calcium Influx through ER-Mitochondria Axis with SERPINB11 Inhibition in Epithelial Ovarian Cancer

Ovarian cancer is the leading cause of gynecological cancer-related mortality. The anticancer effect of eupatilin, a family of flavonoids, is known in many cancer types, but it is unclear what mechanism it plays in ovarian cancer. In this study, eupatilin promoted cell death of ovarian cancer cells by activating caspases, cell cycle arrest, reactive oxygen species (ROS) generation, calcium influx, disruption of the endoplasmic reticulum (ER)–mitochondria axis with SERPINB11 inhibition, and downregulation of phosphoinositide 3-kinase (PI3K) and mitogen activated protein kinase (MAPK) pathways. Additionally, eupatilin-reduced SERPINB11 expression enhanced the effect of conventional chemotherapeutic agents against ovarian cancer cell progression. Cotreatment with siSERPINB11 and eupatilin increased calcium-ion-dependent apoptotic activity in ovarian cancer cells. Although there were no significant toxic effects of eupatilin on embryos, eupatilin completely inhibited tumorigenesis in a zebrafish xenograft model. In addition, eupatilin suppressed angiogenesis in zebrafish transgenic models. Collectively, downregulating SERPINB11 with eupatilin against cancer progression may improve therapeutic activity.

Impact of Antioxidant Natural Compounds on the Thyroid Gland and Implication of the Keap1/Nrf2 Signaling Pathway

BACKGROUND

Natural compounds with potential antioxidant properties have been used in the form of food supplements or extracts with the intent to prevent or treat various diseases. Many of these compounds can activate the cytoprotective Nrf2 pathway. Besides, some of them are known to impact the thyroid gland, often with potential side-effects, but in other instances, with potential utility in the treatment of thyroid disorders.

OBJECTIVE

In view of recent data regarding the multiple roles of Nrf2 in the thyroid, this review summarizes the current bibliography on natural compounds that can have an effect on thyroid gland physiology and pathophysiology, and it discusses the potential implication of the Nrf2 system in the respective mechanisms.

METHODS & RESULTS

Literature searches for articles from 1950 to 2018 were performed in PubMed and Google Scholar using relevant keywords about phytochemicals, Nrf2 and thyroid. Natural substances were categorized into phenolic compounds, sulfur-containing compounds, quinones, terpenoids, or under the general category of plant extracts. For individual compounds in each category, respective data were summarized, as derived from in vitro (cell lines), preclinical (animal models) and clinical studies. The main emerging themes were as follows: phenolic compounds often showed potential to affect the production of thyroid hormones; sulfur-containing compounds impacted the pathogenesis of goiter and the proliferation of thyroid cancer cells; while quinones and terpenoids modified Nrf2 signaling in thyroid cell lines.

CONCLUSION

Natural compounds that modify the activity of the Nrf2 pathway should be evaluated carefully, not only for their potential to be used as therapeutic agents for thyroid disorders, but also for their thyroidal safety when used for the prevention and treatment of non-thyroidal diseases.

Eupatilin: a natural pharmacologically active flavone compound with its wide range applications

Eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone) is a pharmacologically active flavone which has been isolated from a variety of medicinal plants. Eupatilin is known to possess various pharmacological properties such as anti-cancer, anti-oxidant, and anti-inflammatory. It is speculated that eupatilin could be subjected to structural optimization for the synthesis of derivative analogs to reinforce its efficacy, to minimize toxicity, and to optimize absorption profiles, which will ultimately lead towards potent drug candidates. Although, reported data acclaim multiple pharmacological activities of eupatilin but further experimentations on its molecular mechanism of action are yet mandatory to elucidate full spectrum of its pharmacological activities.

Cytoprotective effect of eupatilin against indomethacin-induced damage in feline esophageal epithelial cells: relevance of HSP27 and HSP70

Indomethacin is a non-steroidal anti-inflammatory drug with clearly known side effects on the gastrointestinal tract. The purpose of the present study was to investigate whether eupatilin inhibit cell injury induced by indomethacin in cultured feline esophageal epithelial cells (EECs). EECs were used to investigate the ability of eupatilin to induce the expression of heat shock proteins (HSP27 and HSP70) and analyze its cytoprotective effect against indomethacin-induced damage. The treatment of EECs with indomethacin for 8 h decreased cell viability. Western blot analysis showed that the levels of HSPs gradually decreased in cells treated with indomethacin, while eupatilin treatment increased the levels of HSPs. When treated with both indomethacin and eupatilin, the levels of HSPs increased rapidly, and were maintained at 130-140%. In addition, treatment with the specific inhibitors of PTK, PKC, PLC, p38 MAPK, JNKs, and PI3K attenuated the eupatilin-induced expression of HSPs. Pretreatment of EECs with the inhibitors of protein synthesis, actinomycin D or cycloheximide, attenuated the cytoprotective effect of eupatilin on indomethacin-induced cell damage. Reactive oxygen species production was upregulated by indomethacin, but downregulated by eupatilin. Taken together, it was suggested that HSPs were partly responsible for the eupatilin-mediated cytoprotective activity against the indomethacin-induced damage in EECs.

Effects of eupatilin on the contractility of corpus cavernosal smooth muscle through nitric oxide-independent pathways

Eupatilin (5,7-dihydroxy-3,4,6-trimethoxyflavone) is one of the main compounds present in Artemisia species. Eupatilin has both antioxidative and anti-inflammatory properties and a relaxation effect on vascular contraction regardless of endothelial function. We evaluated the relaxant effects of eupatilin on the corpus cavernosum (CC) of rabbits and the underlying mechanisms of its activity in human corpus cavernosum smooth muscle (CCSM) cells. Isolated rabbit CC strips were mounted in an organ bath system. A conventional whole-cell patch clamp technique was used to measure activation of calcium-sensitive K⁺ -channel currents in human CCSM cells. The relaxation effect of eupatilin was evaluated by cumulative addition (10^-5  m ~ 3 × 10^-4  m) to CC strips precontracted with 10^-5  m phenylephrine. Western blotting analysis was performed to measure myosin phosphatase targeting subunit 1 (MYPT1) and protein kinase C-potentiated inhibitory protein for heterotrimeric myosin light chain phosphatase of 17-kDa (CPI-17) expression and to evaluate the effect of eupatilin on the RhoA/Rho-kinase pathway. Eupatilin effectively relaxed the phenylephrine-induced tone in the rabbit CC strips in a concentration-dependent manner with an estimated EC₅₀ value of 1.2 ± 1.6 × 10^-4  m (n = 8, p < 0.05). Iberiotoxin and tetraethylammonium significantly reduced the relaxation effect (n = 8, p < 0.001 and p = 0.003, respectively). Removal of the endothelium or the presence of L-NAME or indomethacin did not affect the relaxation effect of eupatilin. In CCSM cells, the extracellular application of eupatilin 10^-4  m significantly increased the outward currents, and the eupatilin-stimulated currents were significantly attenuated by treatment with 10^-7  m iberiotoxin (n = 13, p < 0.05). Eupatilin reduced the phosphorylation level of MYPT1 at Thr853 of MLCP and CPI-17 at Thr38. Eupatilin-induced relaxation of the CCSM cells via NO-independent pathways. The relaxation effects of eupatilin on CCSM cells were partially due to activation of BK_Ca channels and inhibition of RhoA/Rho-kinase.

Protective effects of ethanol extracts of Artemisia asiatica Nakai ex Pamp. on ageing-induced deterioration in mouse oocyte quality

Following ovulation, oocytes undergo a time-dependent deterioration in quality referred to as post-ovulatory ageing. Although various factors influence the post-ovulatory ageing of oocytes, oxidative stress is a key factor involved in deterioration of oocyte quality. Artemisia asiatica Nakai ex Pamp. has been widely used in East Asia as a food ingredient and traditional medicine for the treatment of inflammation, cancer, and microbial infections. Recent studies have shown that A. asiatica exhibits antioxidative effects. In this study, we investigated whether A. asiatica has the potential to attenuate deterioration in oocyte quality during post-ovulatory ageing. Freshly ovulated mouse oocytes were cultured with 0, 50, 100 or 200 μg/ml ethanol extracts of A. asiatica Nakai ex Pamp. After culture for up to 24 h, various ageing-induced oocyte abnormalities, including morphological changes, reactive oxygen species (ROS) accumulation, apoptosis, chromosome and spindle defects, and mitochondrial aggregation were determined. Treatment of oocytes with A. asiatica extracts reduced ageing-induced morphological changes. Moreover, A. asiatica extracts decreased ROS generation and the onset of apoptosis by preventing elevation of the Bax/Bcl-2 expression ratio during post-ovulatory ageing. Furthermore, A. asiatica extracts attenuated the ageing-induced abnormalities including spindle defects, chromosome misalignment and mitochondrial aggregation. Our results demonstrate that A. asiatica can relieve deterioration in oocyte quality and delay the onset of apoptosis during post-ovulatory ageing.

Luteolin protects mice from severe acute pancreatitis by exerting HO-1-mediated anti-inflammatory and antioxidant effects

Reseda odorata L. has long been used in traditional Asian medicine for the treatment of diseases associated with oxidative injury and acute inflammation, such as endotoxemia, acute lung injury, acute myocardial infarction and hepatitis. Luteolin, the main component of Reseda odorata L., which is also widely found in many natural herbs and vege-tables, has been shown to induce heme oxygenase-1 (HO-1) expression to exert anti-inflammatory and antioxidant effects. In this study, we aimed to examine the effects of luteolin on mice with severe acute pancreatitis (SAP), and to explore the underlying mechanisms. Cerulein and lipopolysaccharide were used to induce SAP in male Institute of Cancer Research (ICR) mice in the SAP group. The SAP group was divided into 4 subgroups, as follows: the vehicle, luteolin, zinc protoporphyrin (ZnPP) only, and luteolin (Lut) + ZnPP (luteolin plus zinc protoporphyrin treatment) groups. The wet/dry weight ratios, hematoxylin and eosin staining and pathological scores of pancreatic tissues were assessed and compared to those of the control mice. Amylase, lipase, nuclear factor-κB (NF-κB) and myeloperoxidase activities, and malondialdehyde, tumor necrosis factor α (TNFα), interleukin (IL)-6, IL-10 and HO-1 levels, as well as the expression of HO-1 were determined in serum and/or pancreatic tissue samples. SAP was successfully induced in male mice compared to normal control mice. The wet/dry weight ratios, pathological scores, and amylase and lipase activity, as well as the levels of TNFα and IL-6 were significantly reduced in the pancreatic tissues of the mice in the Lut group compared with those of the mice in the vehicle group. The Lut group exhibited a significant increase in HO-1 expression in the pancreas and enhanced serum HO-1 and IL-10 levels compared with the vehicle group. The suppression of HO-1 activity in the ZnPP group significantly abolished the protective effects of luteolin. NF-κB expression in the pancreatic tissues from the mice in the Lut + ZnPP group was significantly increased following the suppression of HO-1 activity. On the whole, our findings demonstrate that luteolin protects mice from SAP by inducing HO-1-mediated anti-inflammatory and antioxidant activities, in association with the suppression of the activation of the NF-κB pathway.

ATP-Binding Pocket-Targeted Suppression of Src and Syk by Luteolin Contributes to Its Anti-Inflammatory Action

Luteolin is a flavonoid identified as a major anti-inflammatory component of Artemisia asiatica. Numerous reports have demonstrated the ability of luteolin to suppress inflammation in a variety of inflammatory conditions. However, its exact anti-inflammatory mechanism has not been fully elucidated. In the present study, the anti-inflammatory mode of action in activated macrophages of luteolin from Artemisia asiatica was examined by employing immunoblotting analysis, a luciferase reporter gene assay, enzyme assays, and an overexpression strategy. Luteolin dose-dependently inhibited the secretion of nitric oxide (NO) and prostaglandin E₂ (PGE₂) and diminished the levels of mRNA transcripts of inducible NO synthase (iNOS), tumor necrosis factor- (TNF-) α, and cyclooxygenase-2 (COX-2) in lipopolysaccharide- (LPS-) and pam3CSK-treated macrophage-like RAW264.7 cells without displaying cytotoxicity. Luteolin displayed potent NO-inhibitory activity and also suppressed the nuclear translocation of NF-κB (p65 and p50) via blockade of Src and Syk, but not other mitogen-activated kinases. Overexpression of wild type Src and point mutants thereof, and molecular modelling studies, suggest that the ATP-binding pocket may be the luteolin-binding site in Src. These results strongly suggest that luteolin may exert its anti-inflammatory action by suppressing the NF-κB signaling cascade via blockade of ATP binding in Src and Syk.

Protective effect of Artemisia asiatica (Pamp.) Nakai ex Kitam ethanol extract against cisplatin-induced apoptosis of human HaCaT keratinocytes: Involvement of NF-kappa B- and Bcl-2-controlled mitochondrial signaling

BACKGROUND

Oral mucositis is a common adverse effect of antineoplastic chemotherapy limiting sufficient dose of chemoregimen. Numerous attempts to mitigate chemotherapy-induced oral mucositis have failed to identify an appropriate treatment.

HYPOTHESIS

We hypothesize that Artemisia asiatica (Pamp.) Nakai ex Kitam ethanol extract (Aa-EE) would mitigate cisplatin-induced cytotoxicity to oral mucosal epithelial cells.

STUDY DESIGN

In vitro experimental study.

METHODS

Cell viability and wound healing assay were performed. Apoptosis, mitochondrial membrane potential (MMP) change, and changes in apoptosis-related signaling were demonstrated in human primary keratinocyte (HaCaT).

RESULTS

Cisplatin inhibited HaCaT cell proliferation and migration. Aa-EE protected against these effects. Cisplatin treatment of HaCaT cells caused apoptosis and changes in MMP. Aa-EE inhibited cisplatin-induced apoptosis, and stabilized the cisplatin-induced loss of MMP. Western blots revealed that Aa-EE reduced the expression of cytochrome c and cleaved caspase-3 and inhibited nuclear translocation of nuclear factor-kappa B (NF-κB), compared with the levels observed after cisplatin treatment, whereas Bcl-2 expression was increased by Aa-EE.

CONCLUSION

Collectively, our results suggest that Aa-EE protects HaCaT cells by inhibiting cisplatin-induced mitochondrial damage associated with Bcl-2 activity and by inhibiting nuclear translocation of NF-κB.

Modulation of the pharmacokinetics, therapeutic and adverse effects of NSAIDs by Chinese herbal medicines

INTRODUCTION

Concomitant use of NSAIDs and Chinese herbal medicines (CHMs) is frequent, yet summarized information on their interactions is lacking.

AREAS COVERED

A systematic review of literature in four evidence-based English databases was performed. Articles which reported CHMs altering the pharmacokinetics, therapeutic and adverse effects of NSAIDs were identified and summarized. Such interactions may lead to beneficial, detrimental or no change in outcomes. The current review covers four therapeutic effects of NSAIDs, including: i) anti-inflammatory; ii) analgesic; iii) antiplatelet, cardiovascular and cerebrovascular; and iv) anticancer effects and four adverse effects of NSAIDs, including: i) gastrointestinal ulcer; ii) nephrotoxicity; iii) hepatotoxicity; and iv) antiplatelet effects and bleeding.

EXPERT OPINION

While majority of CHMs demonstrated effectiveness in alleviating NSAIDs-induced adverse effects and potentiating the therapeutic effects, this review provides insights for development of CHMs as add-on medications to NSAIDs therapies. However, since limited information was from well-designed clinical trials, the findings are not yet conclusive and more clinical studies are warranted to provide guidance for healthcare professionals. In future, researches on interactions between NSAIDs and CHMs are expected to grow and modern approaches such as pharmacogenomics might enhance the throughput and accuracy of identifying clinically relevant interactions.

Proanthocyanidin from grape seed extracts protects indomethacin-induced small intestinal mucosal injury

Proanthocyanidin (grape seed proanthocyanidin extracts, GSPEs) is an antioxidant and scavenges free radicals. Excessive oxidative stress and free radical production are major components in the pathogenesis of NSAID-induced small intestinal injury. We investigated the effect of GSPEs on indomethacin-induced intestinal mucosal injury in the rat. Rats were allocated into four groups: the null control group, the indomethacin control group, the low-dose GSPEs group, and the high-dose GSPEs group. GSPEs were administered for 4 days. Then indomethacin and GSPEs were coadministered for the following 2 days by oral route. The dose of indomethacin was 200 mg/Kg. The doses of GSPEs were 100 mg/Kg for low-dose group and 300 mg/Kg for high-dose group. Luminal bleeding was solely observed in one of 5 rats from indomethacin control group. The number of ulcer count was reduced to 0.1 ± 0.3 per rat in GSPEs treated group compared to 1.4 ± 0.5 per rat in indomethacin control group. Submucosal inflammatory cell infiltration was also reduced to 50% in GSPEs treated group. The tissue level of prostaglandin E2 was not affected by GSPEs treatment. GSPEs attenuated the indomethacin-induced small intestinal injury irrespective of the tissue PGE2 depletion and glutathione consumption.

Anti-inflammatory activities and mechanisms of Artemisia asiatica ethanol extract

ETHNOPHARMACOLOGICAL RELEVANCE

Artemisia asiatica Nakai (Compositae) is a representative herbal plant used to treat infection and inflammatory diseases. Although Artemisia asiatica is reported to have immunopharmacological activities, the mechanisms of these activities and the effectiveness of Artemisia asiatica preparations in use are not known.

MATERIALS AND METHODS

To evaluate the anti-inflammatory activities of Artemisia asiatica ethanol extract (Aa-EE), we assayed nitric oxide (NO), tumor necrosis factor (TNF)-α, and prostaglandin E2 (PGE2) in macrophages and measured the extent of tissue injury in a model of gastric ulcer induced in mice by treatment with HCl in EtOH. Putative enzymatic mediators of Aa-EE activities were identified by nuclear fractionation, reporter gene assay, immunoprecipitation, immunoblotting, and kinase assay. Active compound in Aa-EE was identified using HPLC.

RESULTS

Treatment of RAW264.7 cells and peritoneal macrophages with Aa-EE suppressed the production of NO, PGE2, and TNF-α in response to lipopolysaccharide (LPS) and induced heme oxygenase-1 expression. The Aa-EE also ameliorated symptoms of gastric ulcer in HCl/EtOH-treated mice. These effects were associated with the inhibition of nuclear translocation of nuclear factor (NF)-κB and activator protein (AP)-1, implying that the anti-inflammatory action of the Aa-EE occurred through transcriptional inhibition. The upstream regulatory signals Syk and Src for translocation of NF-κB and TRAF6 for AP-1 were identified as targets of this effect. Analysis of Aa-EE by HPLC revealed the presence of luteolin, known to inhibit NO and PGE2 activity.

CONCLUSION

The anti-inflammatory activities attributed to Artemisia asiatica Nakai in traditional medicine may be mediated by luteolin through inhibition of Src/Syk/NF-κB and TRAF6/JNK/AP-1 signaling pathways.

Identification and quantification of the sedative and anticonvulsant flavone glycoside from Chrysanthemum boreale

The flowers or leaves of Chrysanthemum boreale (Compositae) have been traditionally used as herb tea to reduce anxiety, insomnia, and stress. Sedative and anticonvulsant activities were evaluated in mice using pentobarbital-induced sleeping assay and pentylenetetrazole (PTZ)-induced convulsion assay. The flower extract exhibited more potent activities than the extracts of the leaves and stems, and chromatographic isolation yielded the five compounds acacetin, linarin, acacetin 7-O-β-D-glucopyranosyl-(1 → 2)[α-L-rhamnopyranosyl-(1 → 6)]-β-D-glucopyranoside, chlorogenic acid, and 3,5-di-O-caffeoylquinic acid. These compounds were simultaneously analyzed by HPLC, and the method was validated. The contents of linarin, which were shown to be most abundant in C. boreale, were observed in the order of leaf (11.93 mg/g) > flower (8.50 mg/g) > stem (5.60 mg/g). Linarin and its aglycone, acacetin, exhibited sedative and anticonvulsant activities in the present in vivo assays. It can be considered that linarin is one of the active compounds effective against anxiety, insomnia, and stress, with acacetin as its active moiety.

The inhibitory effect of eupatilin on the agonist-induced regulation of vascular contractility

The present study was undertaken to investigate the influence of eupatilin on vascular smooth muscle contractility and to determine the mechanism involved. Denuded aortic rings from male rats were used and isometric contractions were recorded and combined with molecular experiments. Eupatilin more significantly relaxed fluoride-induced vascular contraction than thromboxane A₂ or phorbol ester-induced contraction suggesting as a possible anti-hypertensive on the agonist-induced vascular contraction regardless of endothelial nitric oxide synthesis. Furthermore, eupatilin significantly inhibited fluoride-induced increases in pMYPT1 levels. On the other hand, it didn't significantly inhibit phorbol ester-induced increases in pERK1/2 levels suggesting the mechanism involving the primarily inhibition of Rho-kinase activity and the subsequent phosphorylation of MYPT1. This study provides evidence regarding the mechanism underlying the relaxation effect of eupatilin on agonist-induced vascular contraction regardless of endothelial function.

The Protective Effect of Eupatilin against Hydrogen Peroxide-Induced Injury Involving 5-Lipoxygenase in Feline Esophageal Epithelial Cells

In this study, we focused to identify whether eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone), an extract from Artemisia argyi folium, prevents H₂O₂-induced injury of cultured feline esophageal epithelial cells. Cell viability was measured by the conventional MTT reduction assay. Western blot analysis was performed to investigate the expression of 5-lipoxygenase by H₂O₂ treatment in the absence and presence of inhibitors. When cells were exposed to 600 µM H₂O₂ for 24 hours, cell viability was decreased to 40%. However, when cells were pretreated with 25~150 µM eupatilin for 12 hours, viability was significantly restored in a concentration-dependent manner. H₂O₂-treated cells were shown to express 5-lipoxygenase, whereas the cells pretreated with eupatilin exhibited reduction in the expression of 5-lipoxygenase. The H₂O₂-induced increase of 5-lipoxygenase expression was prevented by SB202190, SP600125, or NAC. We further demonstrated that the level of leukotriene B₄ (LTB₄) was also reduced by eupatilin, SB202190, SP600125, NAC, or nordihydroguaiaretic acid (a lipoxygenase inhibitor) pretreatment. H₂O₂ induced the activation of p38MAPK and JNK, this activation was inhibited by eupatilin. These results indicate that eupatilin may reduce H₂O₂-induced cytotoxicity, and 5-lipoxygenase expression and LTB₄ production by controlling the p38 MAPK and JNK signaling pathways through antioxidative action in feline esophageal epithelial cells.

Ferulic acid induces heme oxygenase-1 via activation of ERK and Nrf2

This study investigated the effect of ferulic acid (FA) on the up-regulation of heme oxygenase-1 (HO-1) in lymphocytes and the molecular mechanisms involved. Lymphocytes were treated with FA (0.001-0.1 μM) for certain times. Cell viability, the activity and level of expression of HO-1, and signal pathways were analyzed. FA significantly upregulated HO-1 expression both at the level of mRNA and protein in lymphocytes. Moreover, FA induced NF-E2-related factor (Nrf2) nuclear translocation and transcriptional activity, which is upstream of FA induced HO-1 expression. In addition, lymphocytes treated with FA exhibited activation of extracellular regulated kinase (ERK) and treatments with U0126 (an ERK kinase inhibitor) attenuated the FA induced activation of Nrf2, resulting in a decrease in HO-1 expression. Zinc protoporphyrin (ZnPP, a HO-1 inhibitor) markedly suppressed cytoprotection from radiation-induced cell damage by FA. Results suggested that the ERK signaling pathway controlled the anti-oxidation of FA by regulating the expression of the antioxidant enzyme HO-1.

The Protective Effect of Quercetin-3-O-β-D-Glucuronopyranoside on Ethanol-induced Damage in Cultured Feline Esophageal Epithelial Cells

Quercetin-3-O-β-D-glucuronopyranoside (QGC) is a flavonoid glucoside extracted from Rumex Aquaticus Herba. We aimed to explore its protective effect against ethanol-induced cell damage and the mechanism involved in the effect in feline esophageal epithelial cells (EEC). Cell viability was tested and 2',7'-dichlorofluorescin diacetate assay was used to detect intracellular H₂O₂ production. Western blotting analysis was performed to investigate MAPK activation and interleukin 6 (IL-6) expression. Exposure of cells to 10% ethanol time-dependently decreased cell viability. Notably, exposure to ethanol for 30 min decreased cell viability to 43.4%. When cells were incubated with 50 µM QGC for 12 h prior to and during ethanol treatment, cell viability was increased to 65%. QGC also inhibited the H₂O₂ production and activation of ERK 1/2 induced by ethanol. Pretreatment of cells with the NADPH oxidase inhibitor, diphenylene iodonium, also inhibited the ethanol-induced ERK 1/2 activation. Treatment of cells with ethanol for 30 or 60 min in the absence or presence of QGC exhibited no changes in the IL-6 expression or release compared to control. Taken together, the data indicate that the cytoprotective effect of QGC against ethanol-induced cell damage may involve inhibition of ROS generation and downstream activation of the ERK 1/2 in feline EEC.

Prevention and management of non-steroidal anti-inflammatory drugs-induced small intestinal injury

Non-steroidal anti-inflammatory drug (NSAID)-induced small bowel injury is a topic that deserves attention since the advent of capsule endoscopy and balloon enteroscopy. NSAID enteropathy is common and is mostly asymptomatic. However, massive bleeding, stricture, or perforation may occur. The pathogenesis of small intestine injury by NSAIDs is complex and different from that of the upper gastrointestinal tract. No drug has yet been developed that can completely prevent or treat NSAID enteropathy. Therefore, a long-term randomized study in chronic NSAID users is needed.

Greater effectiveness of ε-viniferin in red wine than its monomer resveratrol for inhibiting vascular smooth muscle cell proliferation and migration

Resveratrol is a strong candidate for explaining an irreversible correlation between red wine consumption and coronary heart disease. The present study examined the effect of ε-viniferin, a dehydrodimer of resveratrol, on vascular smooth muscle cells (VSMCs), because ε-viniferin functions are poorly understood in spite of its comparable content to resveratrol in red wines and grapes. Both ε-viniferin and resveratrol inhibited platelet-derived growth factor-induced cell proliferation, migration, and reactive oxygen species (ROS) production, in addition to inducing nitric oxide generation. ε-Viniferin was more effective than resveratrol in these effects, except for inhibiting ROS production. The compounds also increased the expression of the antioxidant enzyme, hemeoxygenase-1, via transcription factor Nrf2. The phosphatidylinositol 3-kinase-Akt pathway was implicated in resveratrol-dependent nuclear Nrf2 accumulation, whereas extracellular signal-regulated kinase and p38 were involved in ε-viniferin-induced Nrf2 accumulation. These data suggest that ε-viniferin may function more effectively than resveratrol in different mechanisms and cooperatively with resveratrol in preventing atherosclerosis.

Effects of eupatilin and jaceosidin on cytochrome p450 enzyme activities in human liver microsomes

Eupatilin and jaceosidin are bioactive flavones found in the medicinal herbs of the genus Artemisia. These bioactive flavones exhibit various antioxidant, antiinflammatory, antiallergic, and antitumor activities. The inhibitory potentials of eupatilin and jaceosidin on the activities of seven major human cytochrome P450 enzymes in human liver microsomes were investigated using a cocktail probe assay. Eupatilin and jaceosidin potently inhibited CYP1A2-catalyzed phenacetin O-deethylation with 50% inhibitory concentration (IC₅₀) values of 9.4 μM and 5.3 μM, respectively, and CYP2C9-catalyzed diclofenac 4-hydroxylation with IC₅₀ values of 4.1 μM and 10.2 μM, respectively. Eupatilin and jaceosidin were also found to moderately inhibit CYP2C19-catalyzed [S]-mephenytoin 4'-hydroxylation, CYP2D6-catalyzed bufuralol 1'-hydroxylation, and CYP2C8-catalyzed amodiaquine N-deethylation. Kinetic analysis of human liver microsomes showed that eupatilin is a competitive inhibitor of CYP1A2 with a K_i value of 2.3 μM and a mixed-type inhibitor of CYP2C9 with a K_i value of 1.6 μM. Jaceosidin was shown to be a competitive inhibitor of CYP1A2 with a K_i value of 3.8 μM and a mixed-type inhibitor of CYP2C9 with K_i value of 6.4 μM in human liver microsomes. These in vitro results suggest that eupatilin and jaceosidin should be further examined for potential pharmacokinetic drug interactions in vivo due to inhibition of CYP1A2 and CYP2C9.

Eupatilin inhibits T-cell activation by modulation of intracellular calcium flux and NF-kappaB and NF-AT activity

Eupatilin, one of the pharmacologically active ingredients of Artemisia princeps, exhibits a potent anti-ulcer activity, but its effects on T-cell immunity have not been investigated. Here, we show that eupatilin has a profound inhibitory effect on IL-2 production in Jurkat T cells as well as in human peripheral blood leukocytes. Eupatilin neither influenced clustering of CD3 and LFA-1 to the immunological synapse nor inhibited conjugate formation between T cells and B cells in the presence or absence of superantigen (SEE). Eupatilin also failed to inhibit T-cell receptor (TCR) internalization, thereby, suggesting that eupatilin does not interfere with TCR-mediated signals on the membrane proximal region. In unstimulated T cells, eupatilin significantly induced apoptotic cell death, as evidenced by an increased population of annexin V(+)/PI(+) cells and cleavage of caspase-3 and PARP. To our surprise, however, once cells were activated, eupatilin had little effect on apoptosis, and instead slightly protected cells from activation-induced cell death, suggesting that apoptosis also is not a mechanism for eupatilin-induced T-cell suppression. On the contrary, eupatilin dramatically inhibited I-kappaBalpha degradation and NF-AT dephosphorylation and, consequently, inhibited NF-kappaB and NF-AT promoter activities in PMA/A23187-stimulated T cells. Interestingly, intracellular calcium flux was significantly perturbed in cells pre-treated with eupatilin, suggesting that calcium-dependent cascades might be targets for eupatilin action. Collectively, our results provide evidence for dual regulatory functions of eupatilin: (1) a pro-apoptotic effect on resting T cells and (2) an immunosuppressive effect on activated T cells, presumably through modulation of Ca(2+) flux.

Phosphorylation of Nrf2 at multiple sites by MAP kinases has a limited contribution in modulating the Nrf2-dependent antioxidant response

The bZIP transcription factor Nrf2 has emerged as a pivotal regulator of intracellular redox homeostasis by controlling the expression of many endogenous antioxidants and phase II detoxification enzymes. Upon oxidative stress, Nrf2 is induced at protein levels through redox-sensitive modifications on cysteine residues of Keap1, a component of the E3 ubiquitin ligase that targets Nrf2 for ubiquitin-dependent degradation. The mitogen activated protein kinases (MAPKs) have previously been proposed to regulate Nrf2 in response to oxidative stress. However, the exact role of MAPKs and the underlying molecular mechanism remain poorly defined. Here we report the first evidence that Nrf2 is phosphorylated in vivo by MAPKs. We have identified multiple serine/threonine residues as major targets of MAPK-mediated phosphorylation. Combined alanine substitution on those residues leads to a moderate decrease in the transcriptional activity of Nrf2, most likely due to a slight reduction in its nuclear accumulation. More importantly, Nrf2 protein stability, primarily controlled by Keap1, is not altered by Nrf2 phosphorylation in vivo. These data indicate that direct phosphorylation of Nrf2 by MAPKs has limited contribution in modulating Nrf2 activity. We suggest that MAPKs regulate the Nrf2 signaling pathway mainly through indirect mechanisms.

Inhibitory effect of saponin fraction from Codonopsis lanceolata on immune cell-mediated inflammatory responses

Saponin components are known to be pharmaceutically, cosmetically and nutraceutically valuable principles found in various herbal medicine. In this study, we evaluated the inhibitory role of saponin fraction (SF), prepared from C. lanceolata, an ethnopharmacologically famous plant, on various inflammatory responses managed by monocytes, macrophages, lymphocytes and mast cells. SF clearly suppressed the release of nitric oxide (NO) and tumor necrosis factor (TNF)-alpha, but not prostaglandin E(2) (PGE(2)). While this fraction did not scavenge the reactivity of SNP-induced radicals in RAW264. 7 cells, it negatively modulated the phagocytic uptake of macrophages treated with FITC-dextran. Interestingly, SF completely diminished cell-cell adhesion events induced by both CD29 and CD43, but not cell-fibronectin adhesion. Concanavalin (Con) A [as well phytohemaglutinin A (PHA)]-induced proliferation of splenic lymphocytes as well as interferon (IFN)-gamma production were also clearly suppressed by SF treatment. Finally, SF also significantly blocked the degranulation process of mast cell line RBL-2H3 cell as assessed by DNP-BSA-induced beta-hexosaminidase activity. The anti-inflammatory activities of SF on NO production seemed to be due to inhibition of nuclear factor (NF)-kappaB activation signaling, since it blocked the phosphorylation of inhibitor of kappaB (IkappaB)alpha as well as inducible NO synthase (iNOS) expression. Therefore, these results suggest that SF may be considered as a promising herbal medicine with potent anti-inflammatory actions.

Eupatilin with heme oxygenase-1-inducing ability protects cultured feline esophageal epithelial cells from cell damage caused by indomethacin

We previously reported that eupatilin (5,7-dihydroxy-3,4,6-trimethoxyflavone) extracted from Artemisia asiaitica, augmented the cellular antioxidant defense capacity through induction of the antioxidant protein heme oxygenase-1 (HO-1), thereby protecting ileal smooth muscle cells from nonsteroidal anti-inflammatory drug (NSAID)-induced intestinal toxicity. In the present study, we used cultured feline esophageal epithelial cells (EEC) to investigate the ability of eupatilin to induce expression of HO-1 and to analyze its cytoprotective effect against indomethacin-induced damage, since NSAID users have a higher risk of esophageal ulcers or esophagitis than non-NSAID users. A culture of EEC from cat was prepared. The identity of the cultures was confirmed by immunocytochemistry using cytokeratin antibodies. Western blot analysis showed a concentration- and time- dependent expression of HO-1 in response to eupatilin. Phosphorylation of extracellular regulating protein kinase (ERKs) and Akt, and nuclear translocation of nuclear related factor 2 (Nrf2) were induced by 150 microM eupatilin in a time-dependent manner. Eupatilin-induced HO-1 expression and Nrf2 were partly attenuated by MEK inhibitor PD98059 and almost completely by phosphatidyl-inactiol 3 kinase (PI3K) inhibitor LY294002, but not by c-Jun N-terminal kinase (JNK) inhibitor SP600125 or p38 mitogen activated protein kinase (MAPK) inhibitor SB202190. MTT assay showed that treatment with 2 mM indomethacin for 2 h decreased cell viability to about 41%. Pre-treatment of cells with eupatilin resulted in the dose-dependent inhibition of indomethacin-induced cell damage. We confirmed that ZnPP, an HO-1 inhibitor, repressed eupatilin-induced HO-1 activity and showed the protective effect of eupatilin against indomethacin-induced cell injury. The data suggested that HO-1 was partly responsible for the eupatilin-mediated protective action of esophageal epithelial cells against indomethacin via both ERKs and PI3K/Akt pathways as well as Nrf2 translocation.