Involvement of NO/cGMP signaling in the apoptotic and anti-angiogenic effects of beta-lapachone on endothelial cells in vitro

The thiophene α-terthienylmethanol isolated from Tagetes minuta inhibits angiogenesis by targeting protein kinase C isozymes α and β2

Background: Tumor angiogenesis is considered as a crucial pathologic feature of cancer with a key role in multidrug resistance (MDR). Adverse effects of the currently available drugs and the development of resistance to these remain as the hardest obstacles to defeat.

Objetive: This work explores flora from Argentina as a source of new chemical entities with antiangiogenic activity.

Methods: Tube formation assay using bovine aortic endothelial cells (BAECs) was the experiment of choice to assess antiangiogenic activity. The effect of the pure compound in cell invasiveness was investigated through the trans-well migration assay. The inhibitory effect of the pure compound on VEGFR-2 and PKC isozymes α and β2 activation was studied by molecular and massive dynamic simulations. Cytotoxicity on peripheral blood mononuclear cells and erythrocyte cells was evaluated by means of MTT and hemolysis assay, respectively. In silico prediction of pharmacological properties (ADME) and evaluation of drug-likeness features were performed using the SwissADME online tool.

Results: Among the plants screened, T. minuta, showed an outstanding effect with an IC₅₀ of 33.6 ± 3.4 μg/ml. Bio-guided isolation yielded the terthiophene α-terthienylmethanol as its active metabolite. This compound inhibited VEGF-induced tube formation with an IC₅₀ of 2.7 ± 0.4 μM and significantly impaired the invasiveness of bovine aortic endothelial cells (BAECs) as well as of the highly aggressive breast cancer cells, MDA-MB-231, when tested at 10 μM. Direct VEGFR-2 and PKC inhibition were both explored by means of massive molecular dynamics simulations. The results obtained validated the inhibitory effect on protein kinase C (PKC) isozymes α and β2 as the main mechanism underlying its antiangiogenic activity. α-terthienylmethanol showed no evidence of toxicity against peripheral blood mononuclear and erythrocyte cells.

Conclusion: These findings support this thiophene as a promising antiangiogenic phytochemical to fight against several types of cancer mainly those with MDR phenotype.

Evaluation of the anti-inflammatory effects of synthesised tanshinone I and isotanshinone I analogues in zebrafish

During inflammation, dysregulated neutrophil behaviour can play a major role in a range of chronic inflammatory diseases, for many of which current treatments are generally ineffective. Recently, specific naturally occurring tanshinones have shown promising anti-inflammatory effects by targeting neutrophils in vivo, yet such tanshinones, and moreover, their isomeric isotanshinone counterparts, are still a largely underexplored class of compounds, both in terms of synthesis and biological effects. To explore the anti-inflammatory effects of isotanshinones, and the tanshinones more generally, a series of substituted tanshinone and isotanshinone analogues was synthesised, alongside other structurally similar molecules. Evaluation of these using a transgenic zebrafish model of neutrophilic inflammation revealed differential anti-inflammatory profiles in vivo, with a number of compounds exhibiting promising effects. Several compounds reduce initial neutrophil recruitment and/or promote resolution of neutrophilic inflammation, of which two also result in increased apoptosis of human neutrophils. In particular, the methoxy-substituted tanshinone 39 specifically accelerates resolution of inflammation without affecting the recruitment of neutrophils to inflammatory sites, making this a particularly attractive candidate for potential pro-resolution therapeutics, as well as a possible lead for future development of functionalised tanshinones as molecular tools and/or chemical probes. The structurally related β-lapachones promote neutrophil recruitment but do not affect resolution. We also observed notable differences in toxicity profiles between compound classes. Overall, we provide new insights into the in vivo anti-inflammatory activities of several novel tanshinones, isotanshinones, and structurally related compounds.

A microfluidics-based wound-healing assay for studying the effects of shear stresses, wound widths, and chemicals on the wound-healing process

Collective cell migration plays important roles in various physiological processes. To investigate this collective cellular movement, various wound-healing assays have been developed. In these assays, a “wound” is created mechanically, chemically, optically, or electrically out of a cellular monolayer. Most of these assays are subject to drawbacks of run-to-run variations in wound size/shape and damages to cells/substrate. Moreover, in all these assays, cells are cultured in open, static (non-circulating) environments. In this study, we reported a microfluidics-based wound-healing assay by using the trypsin flow-focusing technique. Fibroblasts were first cultured inside this chip to a cellular monolayer. Then three parallel fluidic flows (containing normal medium and trypsin solution) were introduced into the channels, and cells exposed to protease trypsin were enzymatically detached from the surface. Wounds of three different widths were generated, and subsequent wound-healing processes were observed. This assay is capable of creating three or more wounds of different widths for investigating the effects of various physical and chemical stimuli on wound-healing speeds. The effects of shear stresses, wound widths, and β-lapachone (a wound healing-promoting chemical) on wound-healing speeds were studied. It was found that the wound-healing speed (total area healed per unit time) increased with increasing shear stress and wound width, but under a shear stress of 0.174 mPa the linear healing speed (percent area healed per unit time) was independent of the wound width. Also, the addition of β-lapachone up to 0.5 μM did not accelerate wound healing. This microfluidics-based assay can definitely help in understanding the mechanisms of the wound-healing process and developing new wound-healing therapies.

Efficient Promotion of Autophagy and Angiogenesis Using Mesenchymal Stem Cell Therapy Enhanced by the Low-Energy Shock Waves in the Treatment of Erectile Dysfunction

Background

Mesenchymal stem cell therapy (MSCT) and defocused low-energy shock wave therapy (ESWT) has been shown to ameliorate erectile dysfunction (ED). However, the interactions and effects of action between MSCT and ESWT remain poorly understood. In this study, we investigated the mechanisms of combination therapy with MSCT and ESWT in a rat model of diabetic ED.

Materials and Methods

Eight-week-old male Sprague-Dawley rats were randomly divided into 2 parts. Diabetic rats induced by streptozotocin (65 mg/kg) were randomly divided into 4 groups: (1) DM control group, (2) DM + ESWT group, (3) DM + MSCT group, and (4) DM + ESWT + MSCT group. The sham group was a normal control group (without streptozotocin). MSCT and (or) ESWT were, respectively, administered to each group according to the proposal for 8 weeks. Immediately after recording of intracavernous pressure (ICP), the penis was then harvested for histologic analysis, ELISA, and Western blotting.

Results

The ratio of ICP/MAP was significantly higher in the DM + ESWT + MSCT group than in ESWT or MSCT treated group (P < 0.05). Also, the treatment stimulated angiogenesis and vasodilatation in the corpus cavernosum (P < 0.05). ESWT increased the quantity of MSCs in the corpus cavernosum and also induced MSCs to express more VEGF in vitro and vivo (P < 0.05) which activated the PI3K/AKT/mTOR and NO/cGMP signaling pathways in the corpus cavernosum. The combination approach stimulated autophagy and decreased apoptosis in the corpus cavernosum. NGF and BDNF expressions were higher in the DM + ESWT + MSCT group than in the DM control group (P < 0.01). Furthermore, the treatment promoted the MSC recruitment by inducing penile tissues to express more PECAM and SDF-1.

Conclusions

Combination of LI-ESWT and MSCT can get a better result than a single treatment by expressing more VEGF which can take part in autophagy by triggering the PI3K/AKT/mTOR signaling pathway. This cooperative therapy would provide a new research direction in ED treatment for the future.

Tabetri™ (Tabebuia avellanedae Ethanol Extract) Ameliorates Atopic Dermatitis Symptoms in Mice

Tabebuia avellanedae has been traditionally used as an herbal remedy to alleviate various diseases. However, the plant's pharmacological activity in allergic and inflammatory diseases and its underlying mechanism are not fully understood. Therefore, we investigated the pharmacological activity of Tabetri (T. avellanedae ethanol extract (Ta-EE)) in the pathogenesis of AD. Its underlying mechanism was explored using an AD mouse model and splenocytes isolated from this model. Ta-EE ameliorated the AD symptoms without any toxicity and protected the skin of 2,4-dinitrochlorobenzene- (DNCB-) induced AD mice from damage and epidermal thickness. Ta-EE reduced the secreted levels of allergic and proinflammatory cytokines, including histamine, immunoglobulin E (IgE), interleukin- (IL-) 4, and interferon-gamma (IFN-γ) in the DNCB-induced AD mice. Ta-EE suppressed the mRNA expression of T helper 2-specific cytokines, IL-4 and IL-5, and the proinflammatory cytokine IFN-γ in the atopic dermatitis skin lesions of AD mice. Moreover, Ta-EE suppressed the mRNA expression of IL-4, IL-5, IFN-γ, and another proinflammatory cytokine, IL-12, in the Con A-stimulated splenocytes. It also suppressed IL-12 and IFN-γ in the LPS-stimulated splenocytes. Taken together, these results suggest that Ta-EE protects against the development of AD through the inhibition of mRNA expression of T helper 2-specific cytokines and other proinflammatory cytokines.

Tabetri™ (Tabebuia avellanedae Ethanol Extract) Ameliorates Osteoarthritis Symptoms Induced by Monoiodoacetate through Its Anti-Inflammatory and Chondroprotective Activities

Although osteoarthritis (OA), a degenerative joint disease characterized by the degradation of joint articular cartilage and subchondral bones, is generally regarded as a degenerative rather than inflammatory disease, recent studies have indicated the involvement of inflammation in OA pathogenesis. Tabebuia avellanedae has long been used to treat various diseases; however, its role in inflammatory response and the underlying molecular mechanisms remain poorly understood. In this study, the pharmacological effects of Tabetri (Tabebuia avellanedae ethanol extract (Ta-EE)) on OA pathogenesis induced by monoiodoacetate (MIA) and the underlying mechanisms were investigated using experiments with a rat model and in vitro cellular models. In the animal model, Ta-EE significantly ameliorated OA symptoms and reduced the serum levels of inflammatory mediators and proinflammatory cytokines without any toxicity. The anti-inflammatory activity of Ta-EE was further confirmed in a macrophage-like cell line (RAW264.7). Ta-EE dramatically suppressed the production and mRNA expressions of inflammatory mediators and proinflammatory cytokines in lipopolysaccharide-stimulated RAW264.7 cells without any cytotoxicity. Finally, the chondroprotective effect of Ta-EE was examined in a chondrosarcoma cell line (SW1353). Ta-EE markedly suppressed the mRNA expression of matrix metalloproteinase genes. The anti-inflammatory and chondroprotective activities of Ta-EE were attributed to the targeting of the nuclear factor-kappa B (NF-κB) and activator protein-1 (AP-1) signaling pathways in macrophages and chondrocytes.

Reduction of doxorubicin-induced genotoxicity by Handroanthus impetiginosus in mouse bone marrow revealed by micronucleus assay

Handroanthus impetiginosus has long been used in traditional medicine and various studies have determined the presence of bioactive chemical compounds and potential phytotherapeutics. In this study, the genotoxicity of the lyophilized tincture of H. impetiginosus bark (THI) was evaluated in mouse bone marrow using micronucleus assays. The interaction between THI and genotoxic effects induced by the chemotherapeutic agent, doxorubicin (DXR), was also analyzed. Experimental groups were evaluated 24 to 48 h after treatment with N-nitroso-N-ethylurea (NEU; 50 mg/kg), DXR (5 mg/kg), sodium chloride (NaCl; 150 mM), and THI (0.5-2 g/kg). Antigenotoxic assays were carried out using THI (0.5 g/kg) in combination with NEU or DXR. Analysis of the micronucleated polychromatic erythrocytes (MNPCEs) indicated no significant differences between treatment doses of THI (0.5-2 g/kg) and NaCl. Polychromatic erythrocyte (PCE) to normochromatic erythrocyte (NCE) ratios did not indicate any statistical differences between DXR and THI or NaCl, but there were differences between THI and NaCl. A significant reduction in MNPCEs and PCE/NCE ratios was observed when THI was administered in combination with DXR. This study suggested the absence of THI genotoxicity that was dose-, time-, and gender-independent and the presence of moderate systemic toxicity that was dose-independent, but time- and gender-dependent. The combination of THI and DXR also suggested antigenotoxic effects, indicating that THI reduced genotoxic effects induced by chemotherapeutic agents.

Lapachol and lapachone analogs: a journey of two decades of patent research(1997-2016)

INTRODUCTION

Lapachol (1), β-lapachone (2) and α-lapachone (3) are three well-studied natural products isolated from Tabebuia impetiginosa having most interesting chemodiversity and demonstrating diverse biological effects. Areas covered: The current review summarizes the recent and past discovery of chemotherapeutic agents based on the compounds 1-3. This review presents an overview of patents filed over the past two decades (1997 to 2016) mostly relating to the anticancer effects of these lapachol and lapachone analogues. Expert opinion: The large number of interesting patents published on the therapeutic potential of quinones 1-3 and their synthetic derivatives lends credence to the importance of these molecules. Moreover, these quinones demonstrated potent anticancer effects towards various cancer cell lines and chemical modification of these quinones have led to products displaying enhanced anticancer effects. It is noteworthy that the majority of patents published are on the anticancer effects of quinones 1-3 and their synthetic derivatives along with a limited number of additional biological effects. It is our opinion that in order to get lead compounds, there needs to be a greater focus on the elucidation of the precise mechanism of action of these compounds including SAR and in vivo studies.

β-lapachone-Induced Apoptosis of Human Gastric Carcinoma AGS Cells Is Caspase-Dependent and Regulated by the PI3K/Akt Pathway

β-lapachone is a naturally occurring quinone that selectively induces apoptotic cell death in a variety of human cancer cells in vitro and in vivo; however, its mechanism of action needs to be further elaborated. In this study, we investigated the effects of β-lapachone on the induction of apoptosis in human gastric carcinoma AGS cells. β-lapachone significantly inhibited cellular proliferation, and some typical apoptotic characteristics such as chromatin condensation and an increase in the population of sub-G1 hypodiploid cells were observed in β-lapachone-treated AGS cells. Treatment with β-lapachone caused mitochondrial transmembrane potential dissipation, stimulated the mitochondria-mediated intrinsic apoptotic pathway, as indicated by caspase-9 activation, cytochrome c release, Bcl-2 downregulation and Bax upregulation, as well as death receptor-mediated extrinsic apoptotic pathway, as indicated by activation of caspase-8 and truncation of Bid. This process was accompanied by activation of caspase-3 and concomitant with cleavage of poly(ADP-ribose) polymerase. The general caspase inhibitor, z-VAD-fmk, significantly abolished β-lapachone-induced cell death and inhibited growth. Further analysis demonstrated that the induction of apoptosis by β-lapachone was accompanied by inactivation of the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. The PI3K inhibitor LY29004 significantly increased β-lapachone-induced apoptosis and growth inhibition. Taken together, these findings indicate that the apoptotic activity of β-lapachone is probably regulated by a caspase-dependent cascade through activation of both intrinsic and extrinsic signaling pathways, and that inhibition of the PI3K/Akt signaling may contribute to β-lapachone-mediated AGS cell growth inhibition and apoptosis induction.

Beta-lapachone inhibits pathological retinal neovascularization in oxygen-induced retinopathy via regulation of HIF-1α

Retinal neovascularization in retinopathy of prematurity (ROP) is the most common cause of blindness for children. Despite evidence that hypoxia inducible factor (HIF)-1α -VEGF axis is associated with the pathogenesis of ROP, the inhibitors of HIF-1α have not been established as a therapeutic target in the control of ROP pathophysiology. We investigated the hypothesis that degradation of HIF-1α as a master regulator of angiogenesis in hypoxic condition, using β-lapachone, would confer protection against hypoxia-induced retinopathy without affecting physiological vascular development in mice with oxygen-induced retinopathy (OIR), an animal model of ROP. The effects of β-lapachone were examined after intraocular injection in mice with OIR. Intraocular administration of β-lapachone resulted in significant reduction in hypoxia-induced retinal neovascularization without retinal toxicity or perturbation of developmental retinal angiogenesis. Our results demonstrate that HIF-1α–mediated VEGF expression in OIR is associated with pathological neovascularization, not physiological angiogenesis. Thus, strategies blocking HIF-1α in the developing eye in the pathological hypoxia could serve as a novel therapeutic target for ROP.

A one-pot, three-component reaction for the synthesis of novel 7-arylbenzo[c]acridine-5,6-diones

A one pot domino protocol for an efficient synthesis of 7-arylbenzo[c]acridine-5,6-diones, with a novel nucleus, has been developed by reacting 2-hydroxynaphthalene-1,4-dione, aromatic aldehydes and aromatic amines using environmentally benevolentp-toluene sulphonic acid as a catalyst.

Effect of DNA damage response by quinazolinone analogue HMJ-38 on human umbilical vein endothelial cells: evidence for γH2A.X and DNA-PK-dependent pathway

The present study aims to explore the mechanism of quinazolinone analogue HMJ-38-induced DNA damage in endothelial cells in vitro. We attempt to evaluate the antiangiogenetic response utilizing human umbilical vein endothelial cells (HUVECs). Herein, the results demonstrated that HMJ-38 incubation triggered DNA damage behavior and showed a longer DNA migration in HUVECs based on the comet assay and the analysis of DNA agarose gel electrophoresis to contact DNA smears. We further gained to determine a marker of DNA double strand breaks, phosphorylated histone H2A.X (Ser139) (γH2A.X), in HMJ-38-treated HUVECs by flow cytometry and Western blotting assay. We consider that HMJ-38 has caused an increase in γH2A.X, and DNA damage seemed to mediate through DNA-dependent serine/threonine protein kinase (DNA-PK) binding to Ku70/Ku80 as well as advanced activated p-Akt (Ser473) and stimulated phosphorylated glycogen synthase kinase-3β (p-GSK-3β) conditions in HUVECs. Importantly, the effect of above DNA damage response was prevented by N-acetyl-l-cysteine (a reactive oxygen species scavenger), and NU7026 (a DNA-PK inhibitor) could attenuate DNA-PK catalytic subunit and phosphorylation of H2A.X on Ser139 expression in comparison with HMJ-38 alone treated HUVECs. Therefore, HMJ-38-provoked DNA damage stress in HUVECs probably led to the activation of γH2A.X/DNA-PK/GSK-3β signaling. In summary, our novel finding provides more information addressing the pharmacological approach of newly synthesized HMJ-38 for further development and therapeutic application in antiangiogenetic effect of cancer chemotherapy.

In vitro electrical-stimulated wound-healing chip for studying electric field-assisted wound-healing process

The wound-healing assay is an easy and economical way to quantify cell migration under diverse stimuli. Traditional assays such as scratch assays and barrier assays are widely and commonly used, but neither of them can represent the complicated condition when a wound occurs. It has been suggested that wound-healing is related to electric fields, which were found to regulate wound re-epithelialization. As a wound occurs, the disruption of epithelial barrier short-circuits the trans-epithelial potential and then a lateral endogenous electric field is created. This field has been proved invitro as an important cue for guiding the migration of fibroblasts, macrophages, and keratinocytes, a phenomenon termed electrotaxis or galvanotaxis. In this paper, we report a microfluidic electrical-stimulated wound-healing chip (ESWHC) integrating electric field with a modified barrier assay. This chip was used to study the migration of fibroblasts under different conditions such as serum, electric field, and wound-healing-promoting drugs. We successfully demonstrate the feasibility of ESWHC to effectively and quantitatively study cell migration during wound-healing process, and therefore this chip could be useful in drug discovery and drug safety tests.

N-benzyl-5-phenyl-1H-pyrazole-3-carboxamide promotes vascular endothelial cell angiogenesis and migration in the absence of serum and FGF-2

AIM

To investigate the effect of N-benzyl-5-phenyl-1H-pyrazole-3-carboxamide (BPC) on angiogenesis in human umbilical vein endothelial cells (HUVECs).

METHODS

Capillary-like tube formation on matrigel and cell migration analyses were performed in the absence of serum and fibroblast growth factor (FGF-2). Reactive oxygen species (ROS) were measured using a fluorescent probe, 2', 7'- dichlorodihydrofluorescein (DCHF). The nitric oxide (NO) production of HUVECs was examined using a NO detection kit. Morphological observation under a phase contrast microscope, a viability assay using 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl-tetrazolium (MTT) and a lactate dehydrogenase (LDH) activity analysis by a detection kit were performed to evaluate the toxicity of BPC on HUVECs in the presence of serum and FGF-2. The level of hypoxia-inducible factor 1α (HIF-1α) and the release of vascular endothelial growth factor (VEGF) were measured by Western blot and ELISA, respectively.

RESULTS

In the absence of serum and FGF-2, cells treated with BPC (5-20 μmol/L) rapidly aligned with one another and formed tube-like structures within 12 h. In the presence of serum and FGF-2, cells treated with BPC for 24, 48 and 72 h had no changes in morphology, viability or LDH release compared with the control group. Cell migration in the BPC-treated group was significantly increased compared with the control group. During this process, NO production and ROS level were elevated dramatically, and the levels of HIF-1α and VEGF were increased dependent on the generation of ROS.

CONCLUSION

BPC most effectively promoted angiogenesis and migration in HUVECs in the absence of FGF-2 and serum.

Antidepressant-like action of the ethanolic extract from Tabebuia avellanedae in mice: evidence for the involvement of the monoaminergic system

The antidepressant-like effect of the ethanolic extract obtained from barks of Tabebuia avellanedae, a plant widely employed in folk medicine, was investigated in two predictive models of depression: forced swimming test (FST) and tail suspension test (TST) in mice. Additionally, the mechanisms involved in this antidepressant-like action and the effects of the association of the extract with the antidepressants fluoxetine, desipramine and bupropion in the TST were investigated. The extract from T. avellanedae produced an antidepressant-like effect, in the FST (100 mg/kg, p.o.) and in the TST (10-300 mg/kg, p.o.), without accompanying changes in ambulation when assessed in the open-field test. The anti-immobility effect of the extract (30 mg/kg, p.o.) in the TST was prevented by pre-treatment of mice with ketanserin (5 mg/kg, i.p., a preferential 5-HT(2A) receptor antagonist), prazosin (1 mg/kg, i.p., an alpha(1)-adrenoceptor antagonist), yohimbine (1 mg/kg, i.p., an alpha(2)-adrenoceptor antagonist), propranolol (2 mg/kg, i.p., a beta-adrenoceptor antagonist), sulpiride (50 mg/kg, i.p., a dopamine D(2) receptor antagonist) and SCH23390 (0.05 mg/kg, s.c., a dopamine D(1) receptor antagonist). The combined administration of a subeffective dose of WAY100635 (0.1 mg/kg, s.c., a selective 5-HT(1A) receptor antagonist) and a subeffective dose of the extract (1 mg/kg, p.o.) produced a significant reduction in the immobility time in the TST. In addition, the combination of fluoxetine (1 mg/kg, p.o.), desipramine (0.1 mg/kg, p.o.), or bupropion (1 mg/kg, p.o.) with a subeffective dose of the extract (1 mg/kg, p.o.) produced a synergistic antidepressant-like effect in the TST, without causing hyperlocomotion in the open-field test. It may be concluded that the extract from T. avellanedae produces an antidepressant-like effect in the FST and in the TST that is dependent on the monoaminergic system. Taken together, our results suggest that T. avellanedae deserves further investigation as a putative alternative therapeutic tool that could help the conventional pharmacotherapy of depression.

Combination of reverse and chemical genetic screens reveals angiogenesis inhibitors and targets

We combined reverse and chemical genetics to identify targets and compounds modulating blood vessel development. Through transcript profiling in mice, we identified 150 potentially druggable microvessel-enriched gene products. Orthologs of 50 of these were knocked down in a reverse genetic screen in zebrafish, demonstrating that 16 were necessary for developmental angiogenesis. In parallel, 1280 pharmacologically active compounds were screened in a human cell-based assay, identifying 28 compounds selectively inhibiting endothelial sprouting. Several links were revealed between the results of the reverse and chemical genetic screens, including the serine/threonine (S/T) phosphatases ppp1ca, ppp1cc, and ppp4c and an inhibitor of this gene family; Endothall. Our results suggest that the combination of reverse and chemical genetic screens, in vertebrates, is an efficient strategy for the identification of drug targets and compounds that modulate complex biological systems, such as angiogenesis.

In vitro and in vivo anti-inflammatory effects of taheebo, a water extract from the inner bark of Tabebuia avellanedae

AIM OF STUDY

Tabebuia spp. (Bignoniaceae) are native to tropical rain forests throughout Central and South America and have long been used as a folk medicine to treat bacterial infection, blood coagulation, cancer and inflammatory diseases. In this study, we aimed to demonstrate the ethnopharmacological activity of Tabebuia avellanedae in various in vitro and in vivo inflammatory conditions.

MATERIALS AND METHODS

To do this, LPS-stimulated macrophages and arachidonic acid or croton oil-induced mouse ear edema models were employed.

RESULTS

The water extract (taheebo) of Tabebuia avellanedae significantly suppressed the production of prostaglandin (PG) E(2) and nitric oxide (NO), and blocked the mRNA expression of their catalyzing enzymes (cyclooxygenase [COX)-II] and inducible NO synthase [iNOS], respectively), in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The blockade of inflammatory mediators by taheebo seemed to be the result of the interruption of extracellular signal-related kinase (ERK) activation, according to immunoblotting analysis and the NO assay, where LPS strongly induced the phosphorylation (a hallmark of activation) of ERK, and U0126, a selective ERK inhibitor, was found to strongly inhibit PGE(2) production. Similarly, oral administration of taheebo (100mg/kg) for 1 week completely diminished mouse ear edema induced by arachidonic acid, an activator of COX-II, but not croton oil, an activator of lipoxygenase.

CONCLUSIONS

These data suggest that the ethnopharmacological action of taheebo may be due to its negative modulation of macrophage-mediated inflammatory responses by suppressing PGE(2) production. Thus, this water extract may be developed as a new therapeutic remedy for various inflammatory diseases such as arthritis and atherosclerosis.