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Metal complexes and solvent extraction properties of isonitrosoacetophenone 2-aminobenzoylhydrazone.

Three types of copper complexes as well as an oximate-bridged nickel complex with isonitrosoacetophenone 2-aminobenzoylhydrazone (H(2)L) have been prepared in ethanolic solution and characterized by elemental analyses, IR, (1)H NMR, UV-vis and magnetic susceptibility measurement. IR spectra show the ligand coordinates as a neutral, monoanionic and dianionic O,N,N-tridentate acylhydrazoneoxime ligand depending reaction conditions and metal salts employed. The elemental analyses results, spectroscopic and magnetic data are consistent with the formation of mononuclear copper complexes and binuclear complexes with both copper and nickel. The effects of varying pH and solvent on the absorption behavior of both ligand and complexes have been investigated. The extraction ability of acylhydrazoneoxime ligand has been examined by the liquid-liquid extraction of selected transition metal [Cu(2+), Ni(2+), Co(2+), Cr(3+), Hg(2+), Zn(2+), Cd(2+) and Mn(2+)] cations. The ligand shows strong binding ability toward copper(II) ion.

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N-2-hydroxy-4-methoxyacetophenone-N'-4-nitrobenzoyl hydrazine: synthesis and structural characterization.

A new aroyl hydrazone, N-2-hydroxy-4-methoxyacetophenone-N'-4-nitrobenzoyl hydrazine was prepared by the condensation reaction of 2-hydroxy-4-methoxyacetophenone and 4-nitrobenzoyl hydrazine. Characterization of the compound was done by elemental analysis and electronic, infrared and NMR spectral analyses. The complete structural assignment of the compound was done by NMR studies by using COSY homonuclear and HSQC heteronuclear techniques. The crystal and molecular structure was determined by single crystal X-ray diffraction studies: crystallized in the monoclinic system, space group P2(1)/n, Z=4, a=7.3343(9)A, b=20.3517(9)A, c=10.1375(5)A, alpha=90.00 degrees, beta=95.735(7) degrees and gamma=90.00 degrees. From the crystal structure, it is concluded that the compound exists as the keto isomer in the solid state. There is a completely extended conformation in the central part of the molecule C5C8N1N2C10O2 with an E configuration at the double bond of the hydrazinic bridge.

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Protection of rats against 3-butene-1,2-diol-induced hepatotoxicity and hypoglycemia by N-acetyl-l-cysteine.

3-Butene-1,2-diol (BDD), an allylic alcohol and major metabolite of 1,3-butadiene, has previously been shown to cause hepatotoxicity and hypoglycemia in male Sprague-Dawley rats, but the mechanisms of toxicity were unclear. In this study, rats were administered BDD (250 mg/kg) or saline, ip, and serum insulin levels, hepatic lactate levels, and hepatic cellular and mitochondrial GSH, GSSG, ATP, and ADP levels were measured 1 or 4 h after treatment. The results show that serum insulin levels were not causing the hypoglycemia and that the hypoglycemia was not caused by an enhancement of the metabolism of pyruvate to lactate because hepatic lactate levels were either similar (1 h) or lower (4 h) than controls. However, both hepatic cellular and mitochondrial GSH and GSSG levels were severely depleted 1 and 4 h after treatment and the mitochondrial ATP/ADP ratio was also lowered 4 h after treatment relative to controls. Because these results suggested a role for hepatic cellular and mitochondrial GSH in BDD toxicity, additional rats were administered N-acetyl-l-cysteine (NAC; 200 mg/kg) 15 min after BDD administration. NAC treatment partially prevented depletion of hepatic cellular and mitochondrial GSH and preserved the mitochondrial ATP/ADP ratio. NAC also prevented the severe depletion of serum glucose concentration and the elevation of serum alanine aminotransferase activity after BDD treatment without affecting the plasma concentration of BDD. Thus, depletion of hepatic cellular and mitochondrial GSH followed by the decrease in the mitochondrial ATP/ADP ratio was likely contributing to the mechanisms of hepatotoxicity and hypoglycemia in the rat.

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The NADPH oxidase inhibitor apocynin (acetovanillone) induces oxidative stress.

Apocynin (acetovanillone) is often used as a specific inhibitor of NADPH oxidase. In N11 glial cells, apocynin induced, in a dose-dependent way, a significant increase of both malonyldialdehyde level (index of lipid peroxidation) and lactate dehydrogenase release (index of a cytotoxic effect). Apocynin evoked also, in a significant way, an increase of H(2)O(2) concentration and a decrease of the intracellular glutathione/glutathione disulfide ratio, accompanied by augmented efflux of glutathione and glutathione disulfide. Apocynin induced the activation of both pentose phosphate pathway and tricarboxylic acid cycle, which was blocked when the cells were incubated with glutathione together with apocynin. The cell incubation with glutathione prevented also the apocynin-induced increase of malonyldialdehyde generation and lactate dehydrogenase leakage. Apocynin exerted an oxidant effect also in a cell-free system: indeed, in aqueous solution, it evoked a faster oxidation of the thiols glutathione and dithiothreitol, and elicited the generation of reactive oxygen species, mainly superoxide anions. Our results suggest that apocynin per se can induce an oxidative stress and exert a cytotoxic effect in N11 cells and other cell types, and that some effects of apocynin in in vitro and in vivo experimental models should be interpreted with caution.

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Paeonol attenuates TNBS-induced colitis by inhibiting NF-kappaB and STAT1 transactivation.

Paeonol, a major phenolic component of Moutan Cortex, is known to have anti-inflammatory activity. However, the effect of Paeonol on colitis has not been evaluated and the molecular mechanism of its anti-inflammatory action remains unknown. The aim of this study was to determine if Paeonol enema attenuates trinitrobenzene sulfonic acid (TNBS)-induced colitis in mice. We also investigated the effects of Paeonol in colon cancer-derived CW-2 cells and T cell leukemia-derived Jurkat cells treated with tumor necrosis factor alpha (TNFalpha) and/or interferon gamma (IFNgamma), which play critical roles in TNBS-induced colitis. Paeonol enema attenuated TNBS-induced colitis judging by body weigh reduction, colon length and histological score. Myeloperoxidase activity and inducible nitric oxide synthase (iNOS) production in the colon were also reduced with Paeonol enema. In CW-2 cells, Paeonol inhibited iNOS protein and mRNA expression induced by costimulation of TNFalpha and IFNgamma. Furthermore, Paeonol reduced TNFalpha-induced NF-kappaB transactivation and IFNgamma-induced STAT1 transactivation in CW-2 cells and also in Jurkat cells. These findings suggest that Paeonol enema may be useful for the treatment of colitis.

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Consequences of mitochondrial injury induced by pharmaceutical fatty acid oxidation inhibitors is characterized in human and rat liver slices.

Inhibition of liver mitochondrial beta-oxidation by pharmaceuticals may lead to safety concerns including mitochondrial dysfunction, lipid accumulation, inflammation and necrosis. In this study, the consequences of mitochondrial beta-oxidation inhibition by pharmaceuticals is investigated in human and rat liver slices. The fatty acid oxidation inhibitors Etomoxir and CPI975, inhibit the rate limiting mitochondrial beta-oxidation enzyme carnitine palmitoyltransferase I, while FOX988 and SDZ51-641, sequester mitochondrial coenzyme A to inhibit carnitine palmitoyltransferase II. Mitochondrial dysfunction was evident by a significant decrease of liver slice ATP levels and mitochondrial injury was verified by ultrastructural changes in morphology, manifested as enlarged mitochondria, C- or O-shaped mitochondria, and granular or crystalline inclusions. Gene expression changes were evident prior to changes in mitochondrial morphology. Time- and concentration dependent changes in mitochondrial genes linked with respiration and mitochondrial fatty acid beta-oxidation were associated with an up-regulation of peroxisome fatty acid oxidation genes, likely as a compensatory mechanism for the inhibition of the mitochondrial pathways. Gene expression changes preceding the decline of liver slice ATP and GSH levels included an up-regulation of stress response and oxidative stress gene expression, as well as genes linked with transcription, transporters, proliferation, cell matrix and signaling. In association with the decline of liver slice ATP and GSH was increased apoptosis and inflammation. Caspase activity, a functional indicator of apoptosis, was significantly increased as well as an up-regulation of genes linked with apoptosis. The increased gene and protein expression of the pro-inflammatory cytokine IL-8, produced by endothelial cells, is likely in response to the manifestation of oxidative stress and GSH depletion; further amplifying the oxidative stress response induced by the fatty acid oxidation inhibitors and triggering an inflammatory response. In summary, human and rat liver slices exhibited similar effects to the inhibitors of mitochondrial beta-oxidation, and the mitochondrial injury is associated with apoptosis and inflammation in the liver slices.

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Renal and antibacterial effects induced by myotoxin I and II isolated from Bothrops jararacussu venom.

Bothrops jararacussu myotoxin I (BthTx-I; Lys 49) and II (BthTX-II; Asp 49) were purified by ion-exchange chromatography and reverse phase HPLC. In this work we used the isolated perfused rat kidney method to evaluate the renal effects of B. jararacussu myotoxins I (Lys49 PLA2) and II (Asp49 PLA2) and their possible blockage by indomethacin. BthTX-I (5 microg/ml) and BthTX-II (5 microg/ml) increased perfusion pressure (PP; ct120=110.28+/-3.70 mmHg; BthTX I=171.28+/-6.30*mmHg; BthTX II=175.50+/-7.20*mmHg), renal vascular resistance (RVR; ct120=5.49+/-0.54 mmHg/ml.g(-1)min(-1); BthTX I=8.62+/-0.37*mmHg/ml g(-1)min(-1); BthTX II=8.9+/-0.36*mmHg/ml g(-1)min(-1)), urinary flow (UF; ct(120)=0.14+/-0.01ml g(-1)min(-1); BthTX I=0.32+/-0.05*ml g(-1)min(-1); BthTX II=0.37+/-0.01*ml g(-1)min(-1)) and glomerular filtration rate (GFR; ct120=0.72+/-0.10 ml g(-1)min(-1); BthTX I=0.85+/-0.13*ml g(-1)min(-1); BthTX II=1.22+/-0.28*ml g(-1)min(-1)). In contrast decreased the percent of sodium tubular transport (%TNa(+); ct(120)=79,76+/-0.56; BthTX I=62.23+/-4.12*; BthTX II=70.96+/-2.93*) and percent of potassium tubular transport (%TK(+);ct120=66.80+/-3.69; BthTX I=55.76+/-5.57*; BthTX II=50.86+/-6.16*). Indomethacin antagonized the vascular, glomerular and tubular effects promoted by BthTX I and it's partially blocked the effects of BthTX II. In this work also evaluated the antibacterial effects of BthTx-I and BthTx-II against Xanthomonas axonopodis. pv. passiflorae (Gram-negative bacteria) and we observed that both PLA2 showed antibacterial activity. Also we observed that proteins Also we observed that proteins chemically modified with 4-bromophenacyl bromide (rho-BPB) decrease significantly the antibacterial effect of both PLA2. In conclusion, BthTx I and BthTX II caused renal alteration and presented activity antimicrobial. The indomethacin was able to antagonize totally the renal effects induced by BthTx I and partially the effects promoted by BthTx II, suggesting involvement of inflammatory mediators in the renal effects caused by myotoxins. In the other hand, other effects could be independently of the enzymatic activity of the BthTX II and the C-terminal domain could be involved in both effects promoted for PLA2.

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Lipophilic organic contaminants in the Rhine river, Germany.

Detailed gas chromatographic-mass spectrometric analyses applied to eight Rhine river water samples constituted a comprehensive characterization of the low molecular weight organic contamination. Within the group of predominant anthropogenic contaminants, only a few compounds were characterized as frequently detected or priority pollutants. Numerous compounds exhibiting physiological or ecotoxicological properties are only rarely reported or still unnoticed riverine contaminants. Information on environmental behaviour or ecotoxicological effects is still limited for most of these substances. In particular, several brominated compounds (mono- and dibrominated (methoxyphenyl)propionic acids and hydroxymethylacetophenones) were identified for the first time as environmental contaminants. Quantitative analyses differentiated five groups of pollutants with respect to their concentration profiles. The spatial distribution and the intensity of emission sources on the one hand and the environmental stability as well as the tendency to adsorb on the particulate matter on the other hand determined the quantitative occurrence of individual compounds.

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Insulin-induced vascular endothelial growth factor expression is mediated by the NADPH oxidase NOX3.

Vascular endothelial growth factor (VEGF) is the most potent stimulatory factor of angiogenesis. Its expression is induced by reactive oxygen species (ROS) in hypoxic conditions and by insulin in normoxic cells. Both ROS and insulin can activate mitogen-activated protein kinases (MAPKs) and induce the transcriptional factor Sp1, components that are essential for VEGF gene expression. The aim of this study was to investigate the role of ROS producing NADPH oxidase enzymes (NOX-es) in insulin-regulated VEGF gene activation. To achieve this goal we chose HepG2 cells as our model system as these cells express the NADPH oxidase isoform NOX3 and respond to insulin stimulation with enhanced ROS production and mRNA transcription and production of VEGF. We demonstrate that in control cells insulin stimulation leads to H2O2 generation, a biphasic activation of p42/44 MAPK and the induction of both Sp1 and HIF-1alpha. Transfection of NOX3-specific siRNA abrogates H2O2 production and inhibits exclusively the second phase of p42/44 MAPK phosphorylation and Sp1 DNA binding and thus prevents upregulation of VEGF-A mRNA expression. In conclusion, our results demonstrate that NOX3, a ROS generating NADPH oxidase, plays an integral role in insulin-induced p42/44 MAPK signal transmission and VEGF-A production.

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Alcohol-induced impairment of neuronal nitric oxide synthase (nNOS)-dependent dilation of cerebral arterioles: role of NAD(P)H oxidase.

The goal of the present study was to determine the role of NAD(P)H oxidase in alcohol consumption-induced impairment of nNOS-dependent reactivity in cerebral arterioles. Sprague-Dawley rats were fed an alcohol diet for 2-3 months. We measured the effects of acute (1 hour) and chronic (1 month) treatment with a NAD(P)H oxidase inhibitor, apocynin, on responses of parietal pial arterioles to nNOS-dependent agonists (NMDA and kainate) and an nitric oxide synthase (NOS)-independent agonist (nitroglycerin). In addition, we measured the expression of NAD(P)H oxidase subunits and superoxide production in parietal cortex. Topical application of NMDA and kainate produced dose-related dilation of pial arterioles. However, the magnitude of vasodilation to these agonists was significantly less in alcohol-fed rats. Treatment with apocynin (acute and chronic) did not alter vasodilation in nonalcohol-fed rats, but significantly improved vasodilation in alcohol-fed rats. Response of pial arterioles to nitroglycerin was similar in nonalcohol-fed and alcohol-fed rats, and was not affected by apocynin. In addition, we found an up-regulation of gp91phox and p47phox in parietal cortex of alcohol-fed rats. Finally, alcohol consumption produced an increase in superoxide production under basal conditions and in the presence of NADPH. Acute treatment with apocynin suppressed alcohol consumption-induced superoxide generation. Our findings suggest that NAD(P)H oxidase plays an important role in chronic alcohol consumption-induced impairment of nNOS-dependent dilation of cerebral arterioles.

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Salvianolic acid B from Salvia miltiorrhiza inhibits tumor necrosis factor-alpha (TNF-alpha)-induced MMP-2 upregulation in human aortic smooth muscle cells via suppression of NAD(P)H oxidase-derived reactive oxygen species.

Activated matrix metalloproteinases (MMPs) in patients with acute coronary syndromes may contribute to plaque destabilization. Tumor necrosis factor-alpha (TNF-alpha) enhances NAD (P) H oxidase-dependent reactive oxygen species (ROS) formation and ROS induce MMP-2. In the present study, the effects of a potent water-soluble antioxidant, salvianolic acid B (SalB), derived from a Chinese herb, Salvia miltiorrhiza, on the expression of MMP-2 by TNF-alpha-treated human aortic smooth muscle cells (HASMCs) were investigated. In this study, salvianolic acid B scavenged H2O2 in a dose-dependent manner in test tube. We found that SalB, as well as NADPH oxidase inhibitors, DPI or apocynin, and antioxidant NAC, inhibited TNF-alpha-induced MMP-2 mRNA, protein expression, and gelatinolytic activity in HASMCs in a concentration-dependent manner. We also observed a dose-dependent decrease in ROS production and NADPH oxidase activity induced by TNF-alpha in the presence of SalB. SalB also significantly inhibited angiotensin II or H2O2-induced MMP-2 mRNA and protein expression and gelatinolytic activity in HASMCs. Our data point out that the importance of NADPH oxidase-dependent ROS generation in the control of SalB inhibition of TNF-alpha-induced MMP-2 expression and activity.

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NADPH oxidase inhibition prevents cocaine-induced up-regulation of xanthine oxidoreductase and cardiac dysfunction.

Oxidative stress is involved in the pathogenesis of cocaine-induced cardiomyopathy. In the present study, we aimed to determine the enzymatic sources of reactive oxygen species (ROS) production, namely NADPH oxidase and xanthine oxidoreductase (XOR) in male Wistar rats treated for 7 days with cocaine (2x7.5 mg/kg/day, ip) or cocaine with a NADPH oxidase inhibitor (apocynin, 50 mg/kg/day, po) or a XOR inhibitor (allopurinol, 50 mg/kg/day, po). Cocaine-induced cardiac dysfunction is associated with an increase in NADPH oxidase and XOR activities (59% and 29%, respectively) and a decrease in catalase activity. Apocynin or allopurinol treatment prevents the cocaine-induced cardiac alteration by restoration of cardiac output, stroke volume and fractional shortening. This is associated with a reduction of the myocardial production of superoxide anions and an enhancement of catalase activity. Surprisingly, apocynin treatment prevents XOR up-regulation supporting the hypothesis that NADPH oxidase-derived ROS play a role in modulating ROS production by XOR. These data suggest that NADPH and xanthine oxidase act synergically to form myocardial ROS and clearly demonstrate that their inhibition may be critical in preventing the initiation and progression of cocaine-induced LV dysfunction.

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Inhibition of NAD(P)H oxidase activity blocks vascular endothelial growth factor overexpression and neovascularization during ischemic retinopathy.

Because oxidative stress has been strongly implicated in up-regulation of vascular endothelial growth factor (VEGF) expression in ischemic retinopathy, we evaluated the role of NAD(P)H oxidase in causing VEGF overexpression and retinal neovascularization. Dihydroethidium imaging analyses showed increased superoxide formation in areas of retinal neovascularization associated with relative retinal hypoxia in a mouse model for oxygen-induced retinopathy. The effect of hypoxia in stimulating superoxide formation in retinal vascular endothelial cells was confirmed by in vitro chemiluminescence assays. The superoxide formation was blocked by specific inhibitors of NAD(P)H oxidase activity (apocynin, gp91ds-tat) indicating that NAD(P)H oxidase is a major source of superoxide formation. Western blot and immunolocalization analyses showed that retinal ischemia increased expression of the NAD(P)H oxidase catalytic subunit gp91phox, which localized primarily within vascular endothelial cells. Treatment of mice with apocynin blocked ischemia-induced increases in oxidative stress, normalized VEGF expression, and prevented retinal neovascularization. Apocynin and gp91ds-tat also blocked the action of hypoxia in causing increased VEGF expression in vitro, confirming the specific role of NAD(P)H oxidase in hypoxia-induced increases in VEGF expression. In conclusion, NAD(P)H oxidase activity is required for hypoxia-stimulated increases in VEGF expression and retinal neovascularization. Inhibition of NAD(P)H oxidase offers a new therapeutic target for the treatment of retinopathy.

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Chronic high pressure-induced arterial oxidative stress: involvement of protein kinase C-dependent NAD(P)H oxidase and local renin-angiotensin system.

Regardless of the underlying pathological mechanisms oxidative stress seems to be present in all forms of hypertension. Thus, we tested the hypothesis that chronic presence of high pressure itself elicits increased arterial O(2)(.-) production. Hypertension was induced in rats by abdominal aortic banding (Ab). Rats with Ab had elevated pressure in vessels proximal and normal pressure in vessels distal to the coarctation, yet both vascular beds were exposed to the same circulating factors. Compared to normotensive hind limb arteries (HLAs) hypertensive forelimb arteries (FLAs) exhibited 1) impaired dilations to acetylcholine and the nitric oxide donor S-nitroso-N-acetyl-D,L-penicillamine that were restored by administration of superoxide dismutase; 2) an increased production of O(2)(.-) (measured by lucigenin chemiluminescence and ethidium bromide fluorescence) that was inhibited or reduced by superoxide dismutase, the NAD(P)H oxidase inhibitors diphenyleneiodonium and apocynin, or the protein kinase C (PKC) inhibitors chelerythrine and staurosporine or by the angiotensin-converting enzyme (ACE) inhibitor captopril; and 3) increased ACE activity. In organ culture, exposure of isolated arteries of normotensive rats to high pressure (160 mmHg, for 24 hours) significantly increased O(2)(.-) production compared to that in arteries exposed to 80 mmHg. High pressure-induced O(2)(.-) generation was reduced by inhibitors of ACE and PKC. Incubation of cultured arteries with angiotensin II elicited significantly increased O(2)(.-) generation that was inhibited by chelerythrine. Thus, we propose that chronic presence of high pressure itself can elicit arterial oxidative stress, primarily by activating directly a PKC-dependent NAD(P)H oxidase pathway, but also, in part, via activation of the local renin-angiotensin system.

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Okadaic acid induces sustained activation of NFkappaB and degradation of the nuclear IkappaBalpha in human neutrophils.

Human neutrophils differ from other cells by containing high amount of IkappaBalpha in the nucleus, and this increased nuclear IkappaBalpha accumulation is associated with the inhibition of NFkappaB activity and increased apoptosis. However, the mechanisms regulating NFkappaB activation and IkappaBalpha degradation in human neutrophils are little understood. The objective of this study was to provide a further insight into the mechanisms regulating NFkappaB activity and IkappaBalpha degradation in human neutrophils. We show that okadaic acid (OA), an inhibitor of protein phosphatases PP1 and PP2A, induces sustained activation of NFkappaB and degradation of the nuclear IkappaBalpha, and increases interleukin-8 expression in the neutrophils. Furthermore, inhibitors of protein kinase C-delta (PKCdelta) and IkappaB kinase (IKK) inhibit the OA-induced activation of NFkappaB. Collectively, our results indicate that in human neutrophils, the sustained activation of NFkappaB is regulated by a continuous phosphorylation and degradation of the nuclear IkappaBalpha.

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FGF-2 and TPA induce matrix metalloproteinase-9 secretion in MCF-7 cells through PKC activation of the Ras/ERK pathway.

Matrix metalloproteinases (MMPs) play an important role in cancer metastasis. Here, we investigated the effect of fibroblast growth factor-2 (FGF-2) and 12-O-tetradecanoylphorbol-13-acetate (TPA) on the secretion of type IV collagenases (MMP-2, MMP-9) in breast cancer MCF-7 cells. As shown by gelatin zymography, both FGF-2 and TPA stimulated the secretion of MMP-9 in MCF-7 cells while they did not change the level of MMP-2 secretion. Signaling cascade studies indicated that both FGF-2 and TPA induced Ras activation, c-Raf phosphorylation, mitogen-activated protein kinase/ERK kinase (MEK(1/2)) phosphorylation, and extracellular signal-regulated kinase (ERK(1/2)) phosphorylation. The FGF-2- and TPA-induced MMP-9 secretion was significantly inhibited by transient transfection of MCF-7 cells with dominant negative Ras (Ras-N17) and by treatment with MEK(1/2) inhibitor PD98059. A pan-protein kinase C (PKC) inhibitor, GF109203X, was found to totally abolish the FGF-2- and TPA-induced MMP-9 secretion and ERK(1/2) phosphorylation. Use of isoform-specific PKC inhibitors such as Rotllerin and Gö6976 suggested, moreover, that the PKC-delta isoform is a likely component of FGF-2 and TPA trophic signaling. These results demonstrated that FGF-2 and TPA induce MMP-9 secretion in MCF-7 cells mainly through PKC-dependent activation of the Ras/ERK(1/2) signaling pathway.

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