The alpha-methylene-gamma-butyrolactone moiety in dehydrocostus lactone is responsible for cytoprotective heme oxygenase-1 expression through activation of the nuclear factor E2-related factor 2 in HepG2 cells

Dehydrocostus lactone ameliorates lipid accumulation, insulin resistance, and endoplasmic reticulum stress in palmitate-treated hepatocytes

Fatty liver disease is caused by lipid accumulation in the liver, insulin resistance (IR), reactive oxygen species (ROS), and endoplasmic reticulum (ER) stress. Dehydrocostus lactone (DHE) has anticancer, anti-inflammatory, and anti-ulcer effects. However, its effects on hepatic steatosis and IR remain unclear. In this study, we investigated whether DHE has antisteatotic effect on fatty liver in vitro. Hepatocytes HepG2 and SNU-449 cells were exposed to 0.25 mM palmitate (PA), and then antisteatotic effect was evaluated by treatment with 10 μM DHE. DHE treatment reduced lipid accumulation and lipogenesis factor protein levels, compared with PA-treated hepatocytes. DHE treatment also decreased gluconeogenesis marker expression and recovered IR in PA-treated hepatocytes, and promoted glucose uptake in PA-treated HepG2 cells. Additionally, the levels of ROS and ER stress factors in PA-treated HepG2 cells were reduced by DHE treatment, compared with PA-treated HepG2 cells. Overall, DHE decreased lipid accumulation and lipogenesis factors as well as recovered IR, gluconeogenesis, and glucose uptake by reducing ER stress and ROS levels in PA-treated hepatocytes. Thus, DHE is a potential antisteatotic agent.

An Overview of NRF2-Activating Compounds Bearing α,β-Unsaturated Moiety and Their Antioxidant Effects

The surge of scientific interest in the discovery of Nuclear Factor Erythroid 2 (NFE2)-Related Factor 2 (NRF2)-activating molecules underscores the importance of NRF2 as a therapeutic target especially for oxidative stress. The chemical reactivity and biological activities of several bioactive compounds have been linked to the presence of α,β-unsaturated structural systems. The α,β-unsaturated carbonyl, sulfonyl and sulfinyl functional groups are reportedly the major α,β-unsaturated moieties involved in the activation of the NRF2 signaling pathway. The carbonyl, sulfonyl and sulfinyl groups are generally electron-withdrawing groups, and the presence of the α,β-unsaturated structure qualifies them as suitable electrophiles for Michael addition reaction with nucleophilic thiols of cysteine residues within the proximal negative regulator of NRF2, Kelch-like ECH-associated protein 1 (KEAP1). The physicochemical property such as good lipophilicity of these moieties is also an advantage because it ensures solubility and membrane permeability required for the activation of the cytosolic NRF2/KEAP1 system. This review provides an overview of the reaction mechanism of α,β-unsaturated moiety-bearing compounds with the NRF2/KEAP1 complex, their pharmacological properties, structural activity-relationship and their effect on antioxidant and anti-inflammatory responses. As the first of its kind, this review article offers collective and comprehensive information on NRF2-activators containing α,β-unsaturated moiety with the aim of broadening their therapeutic prospects in a wide range of oxidative stress-related diseases.

Inhibition of thioredoxin-interacting protein may enhance the therapeutic effect of dehydrocostus lactone in cardiomyocytes under doxorubicin stimulation via the inhibition of the inflammatory response

Heart failure (HF) is the leading cause of death around the world, the mortality caused by HF is growing rapidly, and has become a great threaten to both public health and economic growth. Dehydrocostus lactone (DHE) is the active constituent of Saussurea lappa and is widely used in traditional Chinese medicine for its multiple biological functions, including anti-inflammatory, antioxidant and anti-cancer. To the best of our knowledge, DHE's effect on HF has not been clarified. Thioredoxin-interacting protein (TXNIP) regulates the process of oxidative stress and inflammation and leads to an increase in oxidative stress via oxidization of thioredoxin, TXNIP promotes the activation of the immune response by its binding with the NOD-like receptor protein 3 inflammasome. An MTT assay revealed that the overexpression or inhibition of TXNIP markedly decreased or significantly increased the proliferation of H9c2 cells, respectively. Through reverse transcription-quantitative PCR (RT-qPCR) and western blotting, it was determined that the expression of proinflammatory cytokines was significantly decreased with the increased expression of anti-inflammatory cytokines in a TXNIP knockout model. Further study utilizing RT-qPCR and western blotting demonstrated that these effects may be mediated by the nuclear factor erythroid 2-related factor 2/heme oxygenase-1/NF-κB signaling pathway. In conclusion, TXNIP inhibition may promote the therapeutic effect of DHE on oxidative stress-induced damage.

Costunolide, a Sesquiterpene Lactone, Suppresses Skin Cancer via Induction of Apoptosis and Blockage of Cell Proliferation

Costunolide is a naturally occurring sesquiterpene lactone that demonstrates various therapeutic actions such as anti-oxidative, anti-inflammatory, and anti-cancer properties. Costunolide has recently emerged as a potential anti-cancer agent in various types of cancer, including colon, lung, and breast cancer. However, its mode of action in skin cancer remains unclear. To determine the anti-cancer potential of costunolide in skin cancer, human epidermoid carcinoma cell line A431 was treated with costunolide. A lactate dehydrogenase assay showed that costunolide diminished the viability of A431 cells. Apoptotic cells were detected by annexin V/propidium iodide double staining and Terminal deoxynucleotidyl transferase mediated dUTP nick end labeling assay assay, and costunolide induced cell apoptosis via activation of caspase-3 as well as induction of poly-ADP ribose polymerase cleavage in A431 cells. In addition, costunolide elevated the level of the pro-apoptotic protein Bax while lowering the levels of anti-apoptotic proteins, including Bcl-2 and Bcl-xL. To address the inhibitory effect of costunolide on cell proliferation and survival, various signaling pathways, including mitogen-activated protein kinases, signal transducer and activator of transcription 3 (STAT3), nuclear factor κB (NF-κB), and Akt, were investigated. Costunolide activated the p38 and c-Jun N-terminal kinase pathways while suppressing the extracellular signal-regulated kinase (ERK), STAT3, NF-κB, and Akt pathways in A431 cells. Consequently, it was inferred that costunolide suppresses cell proliferation and survival via these signaling pathways. Taken together, our data clearly indicated that costunolide exerts anti-cancer activity in A431 cells by suppressing cell growth via inhibition of proliferation and promotion of apoptosis. Therefore, it may be employed as a potentially tumor-specific candidate in skin cancer treatment.

Dehydrocostus lactone inhibits NFATc1 via regulation of IKK, JNK, and Nrf2, thereby attenuating osteoclastogenesis

Excessive and hyperactive osteoclast activity causes bone diseases such as osteoporosis and periodontitis. Thus, the regulation of osteoclast differentiation has clinical implications. We recently reported that dehydrocostus lactone (DL) inhibits osteoclast differentiation by regulating a nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), but the underlying mechanism remains to be elucidated. Here we demonstrated that DL inhibits NFATc1 by regulating nuclear factor-κB (NF-κB), activator protein-1 (AP-1), and nuclear factor-erythroid 2-related factor 2 (Nrf2). DL attenuated IκBα phosphorylation and p65 nuclear translocation as well as decreased the expression of NF-κB target genes and c-Fos. It also inhibited c-Jun N-terminal kinase (JNK) but not p38 or extracellular signal-regulated kinase. The reporter assay revealed that DL inhibits NF-κB and AP-1 activation. In addition, DL reduced reactive oxygen species either by scavenging them or by activating Nrf2. The DL inhibition of NFATc1 expression and osteoclast differentiation was less effective in Nrf2-deficient cells. Collectively, these results suggest that DL regulates NFATc1 by inhibiting NF-κB and AP-1 via down-regulation of IκB kinase and JNK as well as by activating Nrf2, and thereby attenuates osteoclast differentiation.

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.

Abd-Elhakim Y. Saussurea lappa Ethanolic Extract Attenuates Triamcinolone Acetonide-Induced Pulmonary and Splenic Tissue Damage in Rats via Modulation of Oxidative Stress, Inflammation, and Apoptosis

Background: In this era, worldwide interest has been directed towards using natural antioxidants to guard against drug side effects. Saussurea lappa is a famous medicinal plant with many biologically active compounds. Triamcinolone acetonide (TA) is an extensively used glucocorticoid. Hence, this study explored, for the first time, the possible beneficial effects of S. lappa ethanolic extract on TA-induced oxidative damage in the lung and spleen of rats. Methods: Five experimental groups were used: control group, S. lappa-treated group (600 mg/kg/day, orally), TA-treated group (40 mg/kg/twice/week I/P), S. lappa + TA co-treated group, and S. lappa/TA prophylactic group. Results: TA exposure significantly induced leukocytosis and neutrophilia. In addition, TA significantly reduced the levels of C-reactive protein, interleukin-12, tumor necrosis factor α, and immunoglobulins. Lung Caspase-3 overexpression and splenic CD8⁺ downregulation were also noted in the TA group. TA treatment significantly increased malondialdehyde concentration but reduced superoxide dismutase and glutathione peroxidase activities. S. lappa counteracted the TA oxidative and apoptotic effects. The best results were recorded in the prophylactic group. Conclusions:S. lappa has a remarkable protective effect via its anti-inflammatory, anti-apoptotic, and antioxidant capacity. Thus, it could be a candidate as a natural antioxidant to face glucocorticoid’s harmful side effects.

Antitumor activity and mechanism of costunolide and dehydrocostus lactone: Two natural sesquiterpene lactones from the Asteraceae family

Costunolide (COS) and dehydrocostus lactone (DEH) are two natural sesquiterpene lactones with potential antitcancer activity against a range of cancer cell types both in vitro and in vivo, particularly for breast cancer and leukemia. There are many researches that have been taken to characterize these pathways and to reveal their anticancer mechanisms of action of COS and DEH. However, while there is a great deal of evidence detailing the effects of COS and DEH on considerable signaling pathways and cellular functions, a global view of their mechanism of action remains elusive. This review systematically summarizes the antitumor activity and mechanism of COS and DEH in the recent reports, and discusses the effect of the key active part (α-methylene-γ-butyrolactone) of COS and DEH against cancer. Moreover, we also discuss the antineoplastic activity of COS and DEH derivatives to improve the cytotoxicity and safety index. We believe this review can provide a systemic reference to develop COS and DEH as anticancer agents.

Dehydrocostus lactone attenuates osteoclastogenesis and osteoclast-induced bone loss by modulating NF-κB signalling pathway

Osteolysis is characterized by overactivated osteoclast formation and potent bone resorption. It is enhanced in many osteoclast‐related diseases including osteoporosis and periprosthetic osteolysis. The shortage of effective treatments for these pathological processes emphasizes the importance of screening and identifying potential regimens that could attenuate the formation and function of osteoclasts. Dehydrocostus lactone (DHE) is a natural sesquiterpene lactone containing anti‐inflammatory properties. Here, we showed that DHE suppressed receptor activator of nuclear factor‐κB ligand (RANKL)‐induced osteoclast formation and osteoclast marker gene expression. It also inhibited F‐actin ring formation and bone resorption in a dose‐dependent manner in vitro. Moreover, DHE inhibited the RANKL‐induced phosphorylation of NF‐κB, mitigated bone erosion in vivo in lipopolysaccharide‐induced inflammatory bone loss model and particle‐induced calvarial osteolysis model. Together, these results suggest that DHE reduces osteoclast‐related bone loss via the modulation of NF‐κB activation during osteoclastogenesis indicating that it might be a useful treatment for osteoclast‐related skeletal disorders.

Costunolide inhibits pulmonary fibrosis via regulating NF-kB and TGF-β1/Smad2/Nrf2-NOX4 signaling pathways

Specific study about the inhibitory effect of costunolide (CN) and relevant mechanism is of great significance for the treatment of pulmonary fibrosis. Here, the pharmacological activity of costunolide on the treatment of pulmonary fibrosis was investigated in vivo and in vitro. The in vivo mice study, mice were received intratracheal injection of bleomycin (BLM, 5 mg/kg) on 0 day to obtain BLM-induced pulmonary fibrosis firstly. From 2 day to 21 day, mice were orally administered with different dose of CN (low dose(CNL): 10 mg/kg, high dose(CNH): 20 mg/kg) and pirfenidone (PFD)(positive control, 50 mg/kg). The in vitro cells model, cells were incubated with recombinant human TGF-β1 for 24 h to get TGF-β₁-induced pulmonary fibrosis. Cells were treated differently for 24 h and divided into five groups. Then, the activity of CN was evaluated by the expression level of related protein and the factors of oxidative stress in vivo and in vitro, and the mechanism was tested from the involved channel protein aspect. As a result, from the comparison of multiple factors (α-SMA, collagen type I/III, HYP, MDA, SOD) between pirfenidone group and CN group, it revealed the beneficial effects of CN against BLM-induced and TGF-β₁-induced pulmonary fibrosis. In addition, our study also proved that CN exerted its effects through suppressing the NF-kB dependent inflammation and regulated TGF-β₁/Smad₂/ NOX₄-Nrf₂ signaling pathways. In conclusion, CN could be a potential theraputic candidate for the treatment pulmonary fibrosis in the future.

Diversity Modification and Structure-Activity Relationships of Two Natural Products 1β-hydroxy Alantolactone and Ivangustin as Potent Cytotoxic Agents

Sesquiterpene lactones (STLs) are a class of plant secondary metabolites widely found in nature with potent antitumor activities. In this work, two isolated STLs 1β-hydroxy alantolactone (1) and ivangustin (2) were derivatized through diversity-oriented strategy, and in vitro cytotoxic activity assessments were conducted against six cell lines including HeLa, PC-3, HEp-2, HepG2, CHO and HUVEC. The cytotoxic structure-activity relationship showed that the double bond between C5 and C6 was beneficial to improve activity; C1-OH oxidized derivatives showed a slight stronger activity, comparable to the positive drug etoposide (VP-16). Yet, C1-OH esterified derivatives decreased the potency which were different from those of 1-O-acetylbritannilactone (ABL) reported previously by us, and C13-methylene reductive and spiro derivatives resulted in almost complete ablation of cytotoxic activity. Mechanistic basis of cytotoxicity of the representative compound 1i was assayed to relate with apoptosis and cell cycle arrest. Furthermore, 1i inhibited TNF-α-induced canonical NF-κB signaling in PC-3 cells. Molecular modeling studies exhibited additional hydrogen bond interaction between 1i and the residue Lys37 of p65, indicating that 1i could form covalent protein adducts with Cys38 on p65.

Multiplexed Thiol Reactivity Profiling for Target Discovery of Electrophilic Natural Products

Electrophilic groups, such as Michael acceptors, expoxides, are common motifs in natural products (NPs). Electrophilic NPs can act through covalent modification of cysteinyl thiols on functional proteins, and exhibit potent cytotoxicity and anti-inflammatory/cancer activities. Here we describe a new chemoproteomic strategy, termed multiplexed thiol reactivity profiling (MTRP), and its use in target discovery of electrophilic NPs. We demonstrate the utility of MTRP by identifying cellular targets of gambogic acid, an electrophilic NP that is currently under evaluation in clinical trials as anticancer agent. Moreover, MTRP enables simultaneous comparison of seven structurally diversified α,β-unsaturated γ-lactones, which provides insights into the relative proteomic reactivity and target preference of diverse structural scaffolds coupled to a common electrophilic motif and reveals various potential druggable targets with liganded cysteines. We anticipate that this new method for thiol reactivity profiling in a multiplexed manner will find broad application in redox biology and drug discovery.

Achillolide A Protects Astrocytes against Oxidative Stress by Reducing Intracellular Reactive Oxygen Species and Interfering with Cell Signaling

Achillolide A is a natural sesquiterpene lactone that we have previously shown can inhibit microglial activation. In this study we present evidence for its beneficial effects on astrocytes under oxidative stress, a situation relevant to neurodegenerative diseases and brain injuries. Viability of brain astrocytes (primary cultures) was determined by lactate dehydrogenase (LDH) activity, intracellular ROS levels were detected using 2',7'-dichlorofluorescein diacetate, in vitro antioxidant activity was measured by differential pulse voltammetry, and protein phosphorylation was determined using specific ELISA kits. We have found that achillolide A prevented the H₂O₂-induced death of astrocytes, and attenuated the induced intracellular accumulation of reactive oxygen species (ROS). These activities could be attributed to the inhibition of the H₂O₂-induced phosphorylation of MAP/ERK kinase 1 (MEK1) and p44/42 mitogen-activated protein kinases (MAPK), and to the antioxidant activity of achillolide A, but not to H₂O₂ scavenging. This is the first study that demonstrates its protective effects on brain astrocytes, and its ability to interfere with MAPK activation. We propose that achillolide A deserves further evaluation for its potential to be developed as a drug for the prevention/treatment of neurodegenerative diseases and brain injuries where oxidative stress is part of the pathophysiology.

Potential anti-cancer activities and mechanisms of costunolide and dehydrocostuslactone

Costunolide (CE) and dehydrocostuslactone (DE) are derived from many species of medicinal plants, such as Saussurea lappa Decne and Laurus nobilis L. They have been reported for their wide spectrum of biological effects, including anti-inflammatory, anticancer, antiviral, antimicrobial, antifungal, antioxidant, antidiabetic, antiulcer, and anthelmintic activities. In recent years, they have caused extensive interest in researchers due to their potential anti-cancer activities for various types of cancer, and their anti-cancer mechanisms, including causing cell cycle arrest, inducing apoptosis and differentiation, promoting the aggregation of microtubule protein, inhibiting the activity of telomerase, inhibiting metastasis and invasion, reversing multidrug resistance, restraining angiogenesis has been studied. This review will summarize anti-cancer activities and associated molecular mechanisms of these two compounds for the purpose of promoting their research and application.

Dehydrocostuslactone inhibits LPS-induced inflammation by p38MAPK-dependent induction of hemeoxygenase-1 in vitro and improves survival of mice in CLP-induced sepsis in vivo

We investigated the hypothesis that the administration of dehydrocostuslactone (DL), a sesquiterpene lactone found in Saussurea lappa Clarke (Compositae), might reduce organ failure and increase survival in a cecal ligation and puncture (CLP)-induced mouse model of sepsis due to HO-1 induction. Treatment of RAW264.7 cells with DL increased HO-1 expression in a time- and concentration-dependent manner, and this up-regulation of HO-1 by DL was significantly inhibited by silencing either Nrf2 and p38 or treating cells with SB203580 (a p38MAPK inhibitor), but it was not inhibited in the presence of SP600125 (an ERK inhibitor), PD98059 (a JNK inhibitor), or LY294002 (PI3K inhibitor). As expected, DL concentration dependently inhibited the expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX-2), and the productions of NO and PGE2 in LPS-activated cells, and these inhibitions were reversed by silencing HO-1. Most importantly, administration of DL significantly reduced mortality and reduced serum IL-1β and TNF-α and the infiltration of macrophages into liver tissues of CLP-mice. Inducible NOS expression in lung and liver tissues of CLP-mice was reduced by DL, which was reversed by the co-administration of zinc-protoporphyrin IX (ZnPPIX; a competitive inhibitor of HO-1). Our findings indicate that DL might be useful for the treatment of sepsis.

Protolichesterinic acid derivatives: α-methylene-γ-lactones as potent dual activators of PPARγ and Nrf2 transcriptional factors

PPARγ and Nrf2 are important transcriptional factors involved in many signaling pathways, especially in the anti-infectious response of macrophages. Compounds bearing a Michael acceptor moiety are well known to activate such transcriptional factors, we thus evaluated the potency of α,β-unsaturated lactones synthesized using fluorous phase organic synthesis. Compounds were first screened for their cytotoxicity in order to select lactones for PPARγ and Nrf2 activation evaluation. Among them, two α-methylene-γ-lactones were identified as potent dual activators of PPARγ and Nrf2 in macrophages.

The cytoprotective effect of sulfuretin against tert-butyl hydroperoxide-induced hepatotoxicity through Nrf2/ARE and JNK/ERK MAPK-mediated heme oxygenase-1 expression

Sulfuretin is one of the major flavonoid components in Rhus verniciflua Stokes (Anacardiaceae) isolates. In this study, we investigated the protective effects of sulfuretin against tert-butyl hydroperoxide (t-BHP)-induced oxidative injury. The results indicated that the addition of sulfuretin before t-BHP treatment significantly inhibited cytotoxicity and reactive oxygen species (ROS) production in human liver-derived HepG2 cells. Sulfuretin up-regulated the activity of the antioxidant enzyme heme oxygenase (HO)-1 via nuclear factor E2-related factor 2 (Nrf2) translocation into the nucleus and increased the promoter activity of the antioxidant response element (ARE). Moreover, sulfuretin exposure enhanced the phosphorylation of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase 1/2 (ERK1/2), which are members of the mitogen-activated protein kinase (MAPK) family. Furthermore, cell treatment with a JNK inhibitor (SP600125) and ERK inhibitor (PD98059) reduced sulfuretin-induced HO-1 expression and decreased its protective effects. Taken together, these results suggest that the protective effect of sulfuretin against t-BHP-induced oxidative damage in human liver-derived HepG2 cells is attributable to its ability to scavenge ROS and up-regulate the activity of HO-1 through the Nrf2/ARE and JNK/ERK signaling pathways. Therefore, sulfuretin could be advantageous as a bioactive source for the prevention of oxidative injury.

Sesquiterpenoids in subtribe Centaureinae (Cass.) Dumort (tribe Cardueae, Asteraceae): distribution, (13)C NMR spectral data and biological properties

Asteraceae Bercht. & J. Presl is one of the biggest and most economically important plant families. The taxonomy and phylogeny of Asteraceae is rather complex and according to the latest and most reliable taxonomic classification of Panero & Funk, based on the analysis of nine chloroplast regions, the family is divided into 12 subfamilies and 35 tribes. One of the largest tribes of Asteraceae is Cardueae Cass. with four subtribes (Carlininae, Echinopinae, Carduinae and Centaureinae) and more than 2500 species. Susanna & Garcia-Jacas have organized the genera of Centaureinae (about 800 species) into seven informal groups, which recent molecular studies have confirmed: 1. Basal genera; 2. Volutaria group; 3. Rhaponticum group; 4. Serratula group; 5. Carthamus group; 6. Crocodylium group; 7. Centaurea group. This review summarizes reports on sesquiterpenoids from the Centaureinae subtribe of the Asteraceae family, as well as the (13)C NMR spectral data described in the literature. It further reviews studies concerning the biological activities of these metabolites. For this work, literature data on sesquiterpenes from the Centaureinae subtribe were retrieved with the help of the SciFinder database and other similar data banks. All entries from 1958 until the end of 2011 were considered. This review is addressed to scientists working in the metabolomics field such as chemists, botanists, etc., the spectroscopic data reported make this work a good tool for structural elucidation, the biological section gives useful information to those who wish to study the structure activity relationships.

Effects of a water-soluble curcumin protein conjugate vs. pure curcumin in a diabetic model of erectile dysfunction

INTRODUCTION

Curcumin is involved in erectile signaling via elevation of cyclic guanosine monophosphate (cGMP).

AIM

Assessment of the effects of water-soluble curcumin in erectile dysfunction (ED).

METHODS

One hundred twenty male white albino rats were divided into: 1st and 2nd control groups with or without administration of Zinc protoporphyrin (ZnPP), 3rd and 4th diabetic groups with or without ZnPP, 5th diabetic group on single oral dose of pure curcumin, 6th diabetic group on pure curcumin administered daily for 12 weeks, 7th and 8th diabetic groups on single dose of water-soluble curcumin administered with or without ZnPP, 9th and 10th diabetic groups on water-soluble curcumin administered daily for 12 weeks with or without ZnPP. All curcumin dosage schedules were administered after induction of diabetes.

MAIN OUTCOME MEASURES

Quantitative gene expression of endothelial nitric oxide synthase (eNOS), neuronal NOS (nNOS), inducible NOS (iNOS), heme oxygenase-1 (HO-1), nuclear transcription factor-erythroid2 (Nrf2), NF-Кβ, and p38. Cavernous tissue levels of HO and NOS enzyme activities, cGMP and intracavernosal pressure (ICP).

RESULTS

Twelve weeks after induction of diabetes, ED was confirmed by the significant decrease in ICP. There was a significant decrease in cGMP, NOS, HO enzymes, a significant decrease in eNOS, nNOS, HO-1 genes and a significant elevation of NF-Кβ, p38, iNOS genes. Administration of pure curcumin or its water-soluble conjugate led to a significant elevation in ICP, cGMP levels, a significant increase in HO-1 and NOS enzymes, a significant increase in eNOS, nNOS, HO-1, and Nrf2 genes, and a significant decrease in NF-Кβ, p38, and iNOS genes. Water-soluble curcumin showed significant superiority and more prolonged duration of action. Repeated doses regimens were superior to single dose regimen. Administration of ZnPP significantly reduced HO enzyme, cGMP, ICP/ mean arterial pressure (MAP), HO-1 genes in diabetic groups.

CONCLUSION

Water-soluble curcumin could enhance erectile function with more effectiveness and with more prolonged duration of action.

Okanin, a chalcone found in the genus Bidens, and 3-penten-2-one inhibit inducible nitric oxide synthase expression via heme oxygenase-1 induction in RAW264.7 macrophages activated with lipopolysaccharide

Excess production of nitric oxide by activated macrophages via inducible nitric oxide synthase leads to the development of various inflammatory diseases. Heme oxygenase-1 expression via activation of nuclear factor-erythroid 2-related factor 2 inhibits nitric oxide production and inducible nitric oxide synthase expression in activated macrophages. Okanin is one of the most abundant chalcones found in the genus Bidens (Asteraceae) that is used as various folk medications in Korea and China for treating inflammation. Here, we found that okanin (possessing the α-β unsaturated carbonyl group) induced heme oxygenase-1 expression via nuclear factor-erythroid 2-related factor 2 activation in RAW264.7 macrophages. 3-Penten-2-one, of which structure, as in okanin, possesses the α-β unsaturated carbonyl group, also induced nuclear factor-erythroid 2-related factor 2-dependent heme oxygenase-1 expression, while both 2-pentanone (lacking a double bond) and 2-pentene (lacking a carbonyl group) were virtually inactive. In lipopolysaccharide-activated RAW264.7 macrophages, both okanin and 3-penten-2-one inhibited nitric oxide production and inducible nitric oxide synthase expression via heme oxygenase-1 expression. Collectively, our findings suggest that by virtue of its α-β unsaturated carbonyl functional group, okanin can inhibit nitric oxide production and inducible nitric oxide synthase expression via nuclear factor-erythroid 2-related factor 2-dependent heme oxygenase-1 expression in lipopolysaccharide-activated macrophages.

Two naturally occurring terpenes, dehydrocostuslactone and costunolide, decrease intracellular GSH content and inhibit STAT3 activation

The main purpose of the present study is to envisage the molecular mechanism of inhibitory action ofdehydrocostuslactone (DCE) andcostunolide (CS), two naturally occurring sesquiterpene lactones, towards the activation of signal transducer and activator of transcription 3 (STAT3). We report that, in human THP-1 cell line, they inhibit IL-6-elicited tyrosine phosphorylation of STAT3 and its DNA binding activity with EC₅₀ of 10 µM with concomitantdown-regulation ofthe phosphorylation of the tyrosine Janus kinases JAK1, JAK2 and Tyk2. Furthermore, these compounds that contain an α-β-unsatured carbonyl moiety and function as potent Michael reaction acceptor, induce a rapid drop in intracellular glutathione (GSH) concentration by direct interaction with it, thereby triggering S-glutathionylation of STAT3. Dehydrocostunolide (HCS), the reduced form of CS lacking only the α-β-unsaturated carbonyl group, fails to exert any inhibitory action. Finally, the glutathione ethylene ester (GEE), the cell permeable GSH form, reverts the inhibitory action of DCE and CS on STAT3 tyrosine phosphorylation. We conclude that these two sesquiterpene lactones are able to induce redox-dependent post-translational modification of cysteine residues of STAT3 protein in order to regulate its function.

Isoalantolactone from Inula helenium caused Nrf2-mediated induction of detoxifying enzymes

Our previous study demonstrated that methanolic extract of Inula helenium (Elecampane) has the potential to induce detoxifying enzymes such as NAD(P)H:(quinone acceptor) oxidoreductase 1 (EC 1.6.99.2) (NQO1, QR) activity and glutathione S-transferase (GST) and found isoalantolactone and alantolactone as the active components. In this study we investigated the detoxifying enzyme-inducing potential of isoalantolactone, which is present in I. helenium and has a structure similar to that of alantolactone. The compound induced QR in a dose-dependent manner in both Hepa1c1c7 cells and its mutant BPRc1 cells lacking the arylhydrocarbon receptor translocator. Like with most phase 2 enzyme inducers, other phase 2 detoxifying enzymes, including GST, glutathione reductase, gamma-glutamylcysteine synthetase, and heme oxygenase-1, were also induced by isoalantolactone in a dose-dependent manner in the cultured cells. Furthermore, isoalantolactone caused a proportionate increase in luciferase activity depending upon concentration and exposure time in the reporter assay in which HepG2-C8 cells, transfectants carrying antioxidant response element-luciferase gene, were used. The nuclear translocation of nuclear factor-E2-related factor 2 (Nrf2) was stimulated by the compound and attenuated by phosphatidylinositol 3-kinase inhibitors such as LY294002 and wortmannin. In conclusion, isoalantolactone is a candidate for chemoprevention and acts as potent phase 2 enzyme inducer by stimulating the accumulation of Nrf2 in the nucleus.

Novel water-soluble curcumin derivative mediating erectile signaling

INTRODUCTION

Curcumin is an inducer of heme oxygenase enzyme-1 (HO-1) that is involved in erectile signaling via elevating cyclic guanosine monophosphate (cGMP)levels.

AIM

To assess the effect of oral administration of a water-soluble long-acting curcumin derivative on erectile signaling.

METHODS

Two hundred and thirty six male white albino rats were divided into four groups; group 1 (N = 20) includes control. Group 2 (N = 72) was equally divided into four subgroups; subgroup 1 received pure curcumin (10 mg/kg), subgroup 2 received the long-acting curcumin derivative (2 mg/kg), subgroup 3 received the long-acting curcumin derivative (10 mg/kg), and subgroup 4 received sildenafil (4 mg/kg). Subgroups were sacrificed after the first, second, and third hour. Group 3 (N = 72) was equally divided into the same four subgroups already mentioned and were sacrificed after 24 hours, 48 hours, and 1 week. Group 4 (N = 72) was subjected to intracavernosal pressure (ICP) measurements 1 hour following oral administration of the same previous doses in the same rat subgroups.

MAIN OUTCOME MEASURE

Cavernous tissue HO enzyme activity, cGMP, and ICP.

RESULTS

In group 2, there was a significant progressive maintained elevation of HO activity and cGMP tissue levels starting from the first hour in subgroups 3 and 4, whereas, the rise in HO activity and cGMP started from second hour regarding the other rat subgroups. Sildenafil effect decreased after 3 hours. In group 3, there was a significant maintained elevation of HO activity and cGMP tissue levels extended to 1 week as compared to controls for all rat subgroups that received both forms of curcumin. In group 4, long-acting curcumin derivative exhibited more significant potentiation of intracavernosal pressure as compared to control and to the pure curcumin.

CONCLUSION

Water-soluble long-acting curcumin derivative could mediate erectile function via upregulating cavernous tissue cGMP.

Dimethoxycurcumin, a Synthetic Curcumin Analogue, Induces Heme Oxygenase-1 Expression through Nrf2 Activation in RAW264.7 Macrophages

Curcumin [1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione] induces heme oxygenase-1 (HO-1) expression via activation of the nuclear factor-erythroid-2-related factor 2 (Nrf2), whereas tetrahydrocurcumin [1,7-bis(4-hydroxy-3-methoxyphenyl)-3,5-heptanedione], one of curcumin in vivo metabolites, has no effect on HO-1 expression and Nrf2 activation. The aim of this study was to investigate whether dimethoxycurcumin [1,7-bis(4,3-dimethoxyphenyl)-1,6-heptadiene-3,5-dione], a synthetic curcumin analogue with higher metabolic stability over curcumin, could induce HO-1 expression to the same extent as curcumin in RAW264.7 macrophages. Dimethoxycurcumin and curcumin, but not tetrahydrocurcumin, induced HO-1 expression and Nrf2 nuclear translocation, suggesting that the unsaturated nature of the diarylheptanoid chain of the compounds are crucial for HO-1 expression and Nrf2 activation. Blockage of Nrf2 synthesis by small interfering RNA abolished HO-1 expression by dimethoxycurcumin, indicating that dimethoxycurcumin may induce HO-1 expression via Nrf2 activation. In comparison, dimethoxycurcumin and curcumin had about the same effect on HO-1 expression, suggesting that dimethoxycurcumin retains the HO-1-inducing activity of its parent compound curcumin in RAW264.7 macrophages.