Chemical and biological properties of nordihydroguaiaretic acid

Nordihydroguaiaretic acid (NDGA) is a natural product obtained by the alkaline extraction of dried plants of Larrea tridentata species. Due to the biological properties presented, such as antioxidant, anti-inflammatory, antiviral and cytotoxic capacity, this compound is being increasingly studied. In this review, it was evaluated the benefits of NDGA against different animal models. Besides that, it was found that this compound has antitumor activity similar to its synthetic derivative terameprocol in prostate tumors. The hypoglycemic effect may be evidenced by the inhibition of sugar uptake by NDGA; in obesity, studies have observed that NDGA presented a positive regulatory effect for Peroxisome proliferator-activated receptors (PPAR-α) involved in the oxidation of hepatic fatty acids and reduced the expression of lipogenic genes. Regarding its antioxidant potential, its mechanism is related to the ability to in vitro scavenging reactive substances. Although there are several studies demonstrating the benefits of using NDGA, there are also reports of its toxicity, mainly of liver damage and nephrotoxicity

Efecto sinérgico de ácidos grasos poliinsaturados (PUFAS) y ácidos nordihidroguaiaretico (NDGA) sobre parámetros metabólicos, inflamatorios y de oxidación celular en el desarrollo de diabetes espontánea de un modelo experimental

La Diabetes Mellitus (DM) es una enfermedad compleja con progresivas alteraciones en los parámetros metabólicos incluyendo también un estado de inflamación crónica sistémica de bajo grado, entre otros. La actividad física y la planificación nutricional son herramientas efectivas para prevenir y tratar la enfermedad y disminuir otros factores de riesgo relacionados, como el sobrepeso y obesidad. El modelo animal de ratas Stillman Salgado (ratas eSS) se basa en el empleo experimental de una variedad de ratas Wistar las cuales desarrollan espontánea y progresivamente una forma de DM, habitualmente con repercusiones clínicas y de laboratorio de leves a moderadas. Con la evolución de la DM, los animales muestran progresiva intolerancia a la glucosa, con aumento de los niveles plasmáticos de insulina, triglicéridos y glucosa, entre otros parámetros alterados. Es ampliamente conocido que los perfiles lipídicos influyen y son influidos por diversas patologías, como por ejemplo enfermedad Cardiovascular, DM, obesidad, entre otras. La relación entre la ingesta de ácidos grasos poli insaturados (PUFAs) de la serie omega 6/omega 3 (ω-6/ ω-3) menor a 4:1 se relaciona con bajos índices inflamatorios y de oxidación celular, hallándose en la dieta denominada “occidental” un desbalanceado consumo de carnes rojas, un disbalance en la alimentación respecto a estos PUFAs, con porcentajes aún mayores a 10:1, inclusive llegando a 40:1. Ello colabora para que se produzca un aumento progresivo de moléculas inflamatorias (eicosanoides en general) a partir de ácido araquidónico (AA), PUFAs ω-6, constituyendo la denominación común en estas entidades el establecimiento de inflamación crónica sostenida de bajo grado (CLGI)...

Diabetes Mellitus (DM) is a complex disease with alterations inmetabolic and inflammatory indices. Stillman Salgado rats (eSS rats) spontaneouslydevelop DM once reached middle age showing progressive impairment of glucosetolerance along with hypertriglyceridemia, hyperglycemia, and hyperinsulinemia. Inthe present study, we analyzed the effects of ω-3 and ω-6 polyunsaturated fatty acids(PUFAs) supplementation with or without nordihydroguaiaretic acid (NDGA), astrong, natural antioxidant and Lipooxygenase inhibitor molecule, isolated from nativeflora plants, on metabolic and inflammatory parameters in eSS rats to search whetherwhich combination may delay the development of DM and/or prevent its progression.MATERIALS AND METHODS: eSS rats after 10th days stopping breastfeed weremonthly administered intraperitoneal (IP) with ω-3 commercial fish oil (EPA 35% andDHA 40% 6,25mg/Kg) and purchased ω-6 (90% arachidonic acid 6,25mg/Kg)throughout twelve months. Two additional groups of rats received IP 1.9mg/KgNDGA along with w-3 and w-6 fatty acids. Blood and tissue samples were collectedto determine plasma TGs (TG), total plasma fatty acids (FA), A1C hemoglobin, Creactiveprotein (CRP), Gamma glutamyl transpeptidase (GGTP), lipo and hydroperoxides, nitrites and IL-6 (in plasma and in different organs as liver, kidney andpancreas) and then underwent oral glucose tolerance test (OGTT) as well...

Larvicidal activity of crude extracts from Larrea cuneifolia (Zygophyllaceae) and of its metabolite nordihydroguaiaretic acid against the vector Culex quinquefasciatus (Diptera: Culicidae)

INTRODUCTION: The aim of the present study was to analyze the larvicidal activity of different crude extracts of Larrea cuneifolia and its most abundant lignan, nordihydroguaiaretic acid (NDGA), against Culex quinquefasciatus. METHODS: Chloroform, methanol, and aqueous extracts from L. cuneifolia and NDGA were tested against larvae of Cx. quinquefasciatus under laboratory conditions. RESULTS: The chloroform extract showed the highest larvicidal effect, with an estimated LC50 of 0.062 mg/ml. NDGA also demonstrated significant larvicidal activity with an estimated LC50 of 0.092 mg/ml. CONCLUSIONS: These results indicate that the chloroform extract of L. cuneifolia and NDGA are promising insecticides of botanical origin that could be useful for controlling Cx. quinquefasciatus.

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 microM H2O2 for 24 hours, cell viability was decreased to 40%. However, when cells were pretreated with 25~150 microM 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.

Effects of Lipoxygenase Inhibitor on Diabetic Nephropathy in Rats: Decreasing Proteinuria and Preserving Renal Function / 대한신장학회지

PURPOSE: Oxidative stress leads to an increased production of lipoxygenase derivatives in diabetic nephropathy. Thus, we hypothesized that lipoxygenase inhibitor, nordihydroguaiaretic acid (NDGA), ha the effects of decreasing proteinuria and preserving renal function in streptozotocin (STZ)-induced diabetic rats. METHODS: 45 Sprague-Dawley rats were divided into three groups; (A) treatment with lipoxygenase inhibitor, NDGA in diabetic nephropathy rats, (B) treatment with dimethyl sulfoxide (DMSO) as a vehicle in STZ-induced diabetic rats, (C) normal control group with subcutaneous injection of normal saline. Diabetes was induced by a single intraperitoneal injection of STZ (65 mg/kg) in rats of group A and B. After the 4th week of STZ injection, NDGA (10 mg/kg) and DMSO were given subcutaneously for another 4 weeks in group A and B respectively. RESULTS: The NDGA-treated diabetic rats exhibited significantly decreased urinary albumin excretion. Serum creatinine and blood urea nitrogen concentrations were increased in both group A and B, and tend to be higher in group B than group A. Twenty-four-hour urine creatinine clearances were increased in both group A and B after injection of STZ. Pathologic alterations of kidney were observed after injection of STZ, and then attenuated after administration of NDGA. CONCLUSION: These results suggest the potential of lipoxygenase inhibitor as a complementary therapy for the prevention and treatment of diabetic nephropathy.

Nordihydroguaiaretic acid partially inhibits inflammatory responses after focal cerebral ischemia in rats / 生理学报

The aim of the present study is to investigate the role of nordihydroguaiaretic acid (NDGA) on inflammatory cells accumulation after focal cerebral ischemia and the underlying mechanism. Focal cerebral ischemia was induced by 30 min of middle cerebral artery occlusion (MCAO) followed by 72 h of reperfusion. NDGA (5 and 10 mg/kg) was administered intraperitoneally 30 min, 2, 24, 48 h after reperfusion, respectively. The brain injuries were observed by neurological and histological examination. Endogenous IgG exudation, neutrophils and macrophages/microglia accumulation, and intercellular adhesion molecule-1 (ICAM-1) protein expression were determined by immunohistochemistry 72 h after reperfusion. ICAM-1 mRNA was determined by RT-PCR 72 h after reperfusion. The catalysates of 5-lipoxygenase (5-LOX), leukotriene B4 (LTB4) and cysteinyl leukotrienes (CysLTs), were evaluated by ELISA 3 h after reperfusion. The results showed that NDGA ameliorated neurological dysfunction, decreased infarct volume, and inhibited endogenous IgG exudation, neutrophils infiltration, ICAM-1 mRNA and protein expression 72 h after reperfusion. Moreover, NDGA reduced the levels of LTB4 and CysLTs 3 h after reperfusion. However, NDGA did not reduce the accumulation of macrophages/microglia 72 h after reperfusion. These results suggest that NDGA decreases neutrophil infiltration in the subacute phase of focal cerebral ischemia via inhibiting 5-LOX activation.

Arachidonic Acid Activates K+-Cl--cotransport in HepG2 Human Hepatoblastoma Cells

K+-Cl--cotransport (KCC) has been reported to have various cellular functions, including proliferation and apoptosis of human cancer cells. However, the signal transduction pathways that control the activity of KCC are currently not well understood. In this study we investigated the possible role of phospholipase A2 (PLA2)-arachidonic acid (AA) signal in the regulatory mechanism of KCC activity. Exogenous application of AA significantly induced K+ efflux in a dose-dependent manner, which was completely blocked by R-(+)-[2-n-butyl-6,7-dichloro-2-cyclopentyl-2,3-dihydro-1-oxo-1H-inden-5-yl]oxy]acetic acid (DIOA), a specific KCC inhibitor. N-Ethylmaleimide (NEM), a KCC activator-induced K+ efflux was significantly suppressed by bromoenol lactone (BEL), an inhibitor of the calcium-independent PLA2 (iPLA2), whereas it was not significantly altered by arachidonyl trifluoromethylketone (AACOCF3) and p-bromophenacyl bromide (BPB), inhibitors of the calcium-dependent cytosolic PLA2 (cPLA2) and the secretory PLA2 (sPLA2), respectively. NEM increased AA liberation in a dose- and time-dependent manner, which was markedly prevented only by BEL. In addition, the NEM-induced ROS generation was significantly reduced by DPI and BEL, whereas AACOCF3 and BPB did not have an influence. The NEM-induced KCC activation and ROS production was not significantly affected by treatment with indomethacin (Indo) and nordihydroguaiaretic acid (NDGA), selective inhibitors of cyclooxygenase (COX) and lipoxygenase (LOX), respectively. Treatment with 5,8,11,14-eicosatetraynoic acid (ETYA), a non-metabolizable analogue of AA, markedly produced ROS and activated the KCC. Collectively, these results suggest that iPLA2-AA signal may be essentially involved in the mechanism of ROS-mediated KCC activation in HepG2 cells.

Post-treatment Effects of Erythropoietin and Nordihydroguaiaretic Acid on Recovery from Cisplatin-induced Acute Renal Failure in the Rat

5-Lipoxygenase inhibitor and human recombinant erythropoietin might accelerate renal recovery in cisplatin-induced acute renal failure rats. Male Sprague-Dawley rats were randomized into four groups: 1) normal controls; 2) Cisplatin group-cisplatin induced acute renal failure (ARF) plus vehicle treatment; 3) Cisplatin+nordihydroguaiaretic acid (NDGA) group-cisplatin induced ARF plus 5-lipoxygenase inhibitor treatment; 4) Cisplatin+erythropoietin (EPO) group-cisplatin induced ARF plus erythropoietin treatment. On day 10 (after 7 daily injections of NDGA or EPO), urea nitrogen and serum Cr concentrations were significantly lower in the Cisplatin+NDGA and Cisplatin+EPO groups than in the Cisplatin group, and 24 hr urine Cr clearances were significantly higher in the Cisplatin+EPO group than in the Cisplatin group. Semiquantitative assessments of histological lesions did not produce any significant differences between the three treatment groups. Numbers of PCNA(+) cells were significantly higher in Cisplatin, Cisplatin+NDGA, and Cisplatin+EPO groups than in normal controls. Those PCNA(+) cells were significantly increased in Cisplatin+NDGA group. These results suggest that EPO and also NDGA accelerate renal function recovery by stimulating tubular epithelial cell regeneration.

Effects of Celecoxib and Nordihydroguaiaretic Acid on Puromycin Aminonucleoside-Induced Nephrosis in the Rat

The selective cyclooxygenase-2 (COX-2) and 5-lipoxygenase (LOX) inhibitors might inhibit prostaglandin synthesis and reduce proteinuria. The present study was designed to investigate the anti-proteinuric effects of nordihydroguaiaretic acid (NDGA) as compared with celecoxib in puromycin aminonucleoside (PAN) nephrosis rats. Fifty five male Sprague-Dawley rats were divided into 4 groups; A, normal control; B, PAN group; C, PAN+COX-2 inhibitor (celecoxib) group; and D, PAN+5-LOX inhibitor (NDGA) group. After induction of PAN nephrosis through repeated injections of PAN (7.5 and 15 mg/100 g body weight), rats were treated with celecoxib, NDGA, or vehicle for 2 weeks. Twenty four hour urine protein excretions were significantly lower in PAN+celecoxib and PAN+NDGA groups than in PAN group. Serum creatinine (SCr) concentrations and 24 hr urine creatinine clearances (CCr) were not significantly different in the four groups. Electron microscopy showed that podocyte morphology was changed after the induction of PAN nephrosis and was recovered after celecoxib or NDGA administration. Celecoxib significantly recovered the expressions of nephrin, CD2AP, COX-2, and TGF-beta. NDGA also recovered TGF-betaexpression, but did not alter the expressions of nephrin, CD2AP and COX-2. The present study suggested that celecoxib and NDGA might effectively reduce proteinuria in nephrotic syndrome without impairing renal function.

Regulation of pro-inflammatory responses by lipoxygenases via intracellular reactive oxygen species in vitro and in vivo

Reactive oxygen species (ROS) performs a pivotal function as a signaling mediator in receptor-mediated signaling. However, the sources of ROS in this signaling have yet to be determined, but may include lipoxygenases (LOXs) and NADPH oxidase. The stimulation of lymphoid cells with TNF-alpha, IL-1beta, and LPS resulted in significant ROS production and NF-kappaB activation. Intriguingly, these responses were markedly abolished via treatment with the LOXs inhibitor nordihydroguaiaretic acid (NDGA). We further examined in vivo anti-inflammatory effects of NDGA in allergic airway inflammation. Both intraperitoneal and intravenous NDGA administration attenuated ovalbumin (OVA)-induced influx into the lungs of total leukocytes, as well as IL-4, IL-5, IL-13, and TNF-alpha levels. NDGA also significantly reduced serum levels of OVA-specific IgE and suppressed OVA-induced airway hyperresponsiveness to inhaled methacholine. The results of our histological studies and flow cytometric analyses showed that NDGA inhibits OVA-induced lung inflammation and the infiltration of CD11b+ macrophages into the lung. Collectively, our findings indicate that LOXs performs an essential function in pro-inflammatory signaling via the regulation of ROS regulation, and also that the inhibition of LOXs activity may have therapeutic potential with regard to the treatment of allergic airway inflammation.

Advances in the research of lipoxygenase inhibitors / 中南大学学报(医学版)

Lipoxygenase is a protein with non-heme iron atom, which has been discovered in many animals and plants. Lipoxygenase which has a close relationship with human tumors, inflammatory diseases, asthma, arteriosclerosis, and toxic action of chemicals could not only di-oxygenate endogenous polyunsaturated fatty acid to yield bioactive factors such as leukotrienes(LTs), but also has co-oxidation activity to activate xenobiotics. Lipoxygenase inhibitors include hydroxamic acid derivatives, nordihydroguaiaretic acid, flavonoids, FLAP inhibitors and so on. All of them can effectively restrain the catalytic action of lipoxygenase. Literatures demonstrate that the inhibitors can block the formation of relevant bioactive factors and toxic products of xenobiotics clinically which are used to prevent and cure the relevant diseases to keep people healthy.

Effect of nordy on the function of endothelial progenitor cells from human umbilical cord blood induced by vascular endothelial growth factor / 药学学报

This study is to investigate whether the synthesized chiral compound Nordy has influence on the function of endothelial progenitor cells (EPCs) from human umbilical cord blood induced by vascular endothelial growth factor (VEGF). EPCs were isolated from human umbilical cord blood by density gradient centrifugation. After cultured for 7 -10 days, EPCs were prepared for detecting effect of Nordy on proliferation, migration and tubule-forming activity in Matrigel induced by VEGF. Incubation of EPCs with 100 micromol L(-1) Nordy for 24 h initially inhibited the proliferative capacity of EPCs induced by VEGF (P <0.05). Moreover, 25 -50 micromol L(-1) Nordy also exhibited inhibitory effect at 48 -72 h. In addition, 25 - 100 micromol L(-1) Nordy impaired EPCs migratory and tubule-forming capacity in vitro (P < 0.05). Nordy could inhibit in EPCs the functions of proliferation, migration and tubulogenesis induced by VEGF in vitro, which might be a possible mechanism of its anti-EPCs effects.

Protective role of nordihydroguaiaretic acid (NDGA) against the genotoxic damage induced by ethynodiol diacetate in human lymphocytes in vitro.

Antioxidants and plant products are reported to reduce the genotoxic damage of steroids. In our present study we have tested different dosages of nordihydroguaiaretic acid (NDGA) against the genotoxic damage induced by ethynodiol diacetate in the presence of S9 mix. Treatments with nordihydroguaiaretic acid (NDGA) results in the reduction of the genotoxic damage. A significant decrease was observed at all the tested doses of NDGA in sister chromatic exchanges of number of abnormal cells. The results suggest a protective role of NDGA against the genotoxic damage.

Effect of nordy on biological behaviors of malignant glioma cell line U87MG and the analysis of differential expression proteome / 中华病理学杂志

<p><b>OBJECTIVE</b>To explore effects of nordy on biological behaviors of human malignant glioblastoma cell line U87MG in vitro and transplanted tumor in vivo, and to identify the differential proteome upon Nordy induced differentiation.</p><p><b>METHODS</b>Glioblastoma U87MG cells were induced to differentiate by synthetic lipoxygenase inhibitor, Nordy. The drug was also given via peritoneal injection to nude mice (27 mg/kg body weight) bearing orthotopic transplanted tumors of U87MG cells in the brain. The tumor volumes and GFAP expression were measured. Total proteins of U87MG cells after Nordy treatment were analysed by two-dimensional gel electrophoresis. PDQuest 7.1 computer software was used to compare protein profiles of the treated cells with that of untreated control. Differentially expressed proteins were then selected and characterized by matrix assisted laser desorption ionization-time of flight-mass spectrometry. The functional aspects of these proteins were analyzed by bioinformatics.</p><p><b>RESULTS</b>Nordy suppressed both the proliferation of U87MG cells in vitro and the tumor growth of orthotopic transplanted tumors in vivo (P < 0.01). The differentially expressed proteins induced by Nordy included proliferation-associated gene A, alternative splicing factor ASF-3, eukaryotic translation initiation factor 5A, coffilin 1 (non-muscle), beta galactoside binding lectin, glyceraldehyde-3-phosphate dehydrogenase, enolase 1 and an unknown protein.</p><p><b>CONCLUSIONS</b>Nordy promotes the differentiation of glioblastoma cells, by which it may serve as a therapeutic agent. Various proteins identified during Nordy-induced differentiation are involved in the cell proliferation, metabolism, differentiation, apoptosis and gene transcription.</p>

Effect of nordy on FPR function of malignant human glioma cell line U87 / 药学学报

Nordy is a synthesized chrial compound. To investigate the effects of nordy (25 - 100 micromol x L(-1)) on the function of formylpeptide receptor (FPR) of malignant human glioma cells, human glioblastoma cell line U87 was used to detect its proliferation, migration, calcium mobilization, vascular endothelial growth factor (VEGF) mRNA and protein levels after activation of FPR by its agonist N-formyl-methionyl-leucyl-phenylalanine (fMLF). Cell proliferation, migration ability, VEGF mRNA, VEGF protein and calcium mobilization were evaluated by cell counting, chemotaxis assay, RT-PCR, ELISA and spectrometry. Nordy (50 - 100 micromol x L(-1)) potently inhibited the proliferation, migration and calcium mobilization of U87 cells induced by fMLF (P < 0.05). Moreover, 100 micromol x L(-1) nordy showed a significantly impaired VEGF mRNA expression and protein secretion induced by fMLF (P < 0.05). Nordy could inhibit FPR functioning in glioma cell proliferation, migration and angiogenesis, which might be a possible mechanism of its anti-cancer effects.

Influences of Free Fatty Acids on Transmembrane Action Potential and ATP-sensitive Potassium Channel Activity in Rat Myocardium

BACKGROUND: To evaluate the role of free fatty acids on the ischemic myocardium, influences of various free fatty acids upon transmembrane action potential and ATP-sensitive K+(KATP) channel activity were examined in the ventricular myocardium and single cardiac myocytes. METHODS: KATP channel activities were measured in the enzymatically (collagenase) isolated single rat ventricular cardiac myocytes by the method of the excised inside-out and the cell-attached patch clamp, and transmembrane action potentials were recorded using the conventional 3M-KCl microelectode techniques in the rat ventricular myocardium. RESULTS: Free fatty acids [FFAs; arachidonic acid (AA), linoleic acid (LA) and lysophosphatidylcholine (LPC)] reduced the KATP channel activity in a dose-dependent manner in the inside-out patch, and 50%-inhibition concentrations (IC50) were 88 +/- 11.2, 49 +/- 12.5, and 188 +/- 17.4 M respectively. Both frequency of channel opening and the mean open-burst duration were markedly decreased, but the amplitude of single channel currents were not changed by the FFAs. AA (50 micrometer) and LPC (50 micrometer) did not affect the dinitrophenol (DNP, 50 micrometer)-induced KATP channel activity, whereas LA (50 micrometer) had a tendency to reduce the activity. The channel inhibition effects by 10 micrometer AA in the inside-out patch were significantly augmented by diclofenac (10 micrometer), but was not changed by nordihydroguaiaretic acid. FFAs never stimulated KATP channel activity, even in the inside-out patch where KATP channel activity reduced in the presence of internal ATP (100 micrometer). Time for 90% repolarization (APD90) significantly increased during superfusion of the FFAs, to 22 (50 micrometer AA), 24 (50 micrometer LA), and 18 (50 micrometer LPC) % from those of the contol at the time of 10 min superfusion, but the other action potential characteristics were not changed by the FFAs. AA (10 micrometer) attenuated cromakalim (10 micrometer)-induced APD90 shortening effects. CONCLUSION: It was inferred that FFAs inhibit the KATP channel activity directly by themselves and/or indirectly by their metabolites in the rat ventricular cardiomyocytes, and therefore, duration of action potential lengthens to be a burden over the ischemic myocardium accounting for the injury of myocardium at the late stage of ischemia.

Study on the action by PAF on IL-1 modulation in alveolar macrophages: Involvement of endogenous arachidonate metabolites and intracellular Ca++ mobilization

Platelet-activating factor (PAF) enhanced interleukin-1 (IL-1) activity by the interaction with a specific receptor in rat alveolar macrophages. In this study, we investigated the role of endogenous arachidonate metabolites and intracellular calcium mobilization in the PAF-induced IL-1 activity. Alveolar macrophages were preincubated with 5-lipoxygenase and cyclooxygenase inhibitors 30 min before the addition of PAF and lipopolysaccharide (LPS). After 24 h culture, IL-1 activity was measured in the supernate of sample using the thymocyte proliferation assay. Inhibition of 5-lipoxygenase by nordihydroguaiaretic acid and AA-861 completely blocked the PAF-induced enhancement of IL-1 activity with IC50 of 2 micrometer and 5 micrometer, respectively. In contrast, the inhibition of cyclooxygenase pathway by indomethacin and ibuprofen resulted in the potentiation in PAF-induced IL-1 activity with maximal effect at 1 micrometer and 5 micrometer, respectively. In addition, leukotriene B4 and prostaglandin E2 production were observed in PAF-stimulated alveolar macrophage culture. As could be expected, 5-lipoxygenase and cyclooxygenase inhibitors abolished PAFstimulated leukotriene B4 and prostaglandin E2 production, respectively. The effects of PAF on intracellular calcium mobilization in alveolar macrophages were evaluated using the calcium-sensitive dye fura-2 at the single cell level. PAF at any dose between 10-16 and 10-8M did not increase intracellular calcium. Furthermore, there was no effective change of intracellular calcium level when PAF was added to alveolar macrophages in the presence of LPS or LPS + LTB4, and 4, 24 and 48h after treatment of these stimulants. Together, the results indicate that IL-1 activity induced by PAF is differently regulated through subsequent induction of endogenous 5-lpoxygenase and cyclooxygenase pathways, but not dependent on calcium signalling pathway.

Indomethacin, esculetin and nordihydroguaiaretic acid modify arachidonate biosynthesis in rat adrenocortical cells

Se estudio la duración del efecto inhibición que produce la ACTH sobre la incorporación y transformación del ácido [1-14C] eicosatrienoico, en células corticoadrenales aisladas de ratas normales. También se investigó el efecto de la esculetina, indometacina y del ácido nordihidroguaiarético, independientemente o en presencia de ACTH o dibutiril cíclico (diBuAMPc), sobre la biosíntesis de araquidonato. La ACTH y el di BUAMPc produjeron una inhibición significativa en la biosíntese de ácido araquidónico. La depresión producida por la hormona se consideró como un efecto a corto tiempo. El ácido nordihidroguaiarético y la esculetina deprimieron la captación del ácido 20:3 (n=6) en las células corticoadrenales. Este efecto se potenció cuando las células fueron tratadas simultáneamente con ACTH o diBuAMPc. La indometacina no modificó la capacitación del ácido 20:3 (n-6) e incrementó la actividad delta5 desaturante. Este efecto indicaría que, normalmente, los metabolitos producidos por la vía de la negativa sobre la actividad delta5 desaturante producida por la ACTH y el diBuAMPc, y la modulación positiva que se infiere de los resultados obtenidos en el presente trabajo, se puede asumir que existen, por lo menos, dos mecanismos que participan en la formación del ácido 20:4(n-6). Estos mecanismos parecen operar independentemente y probablemente interaccionan produciendo un control bidireccional

The secretory effect of canatoxina ou rat brain synaptosomes involves a lipoxygenase-mediated pathway

Canatoxin (CNTX), a neurotoxic protein, is known to activate platelet secretion and aggregation in vitro through a lipoxygenase-dependent pathway. This study shows that CNTX also induces time and dose-dependent serotonin secretion from rat brain synaptosomes. The secretory effect induced by 6 micronM CNTX was similar to that elicited by 150 mM KCl. Nordihyderoguaiaretic acid (500 micronM) completely abolished CNTX-induced serotonin release while 150 micronM indomethacin had no effect. These data suggest the involvement of the lipoxygenase pathway in neurotransmitter release elicited by CNTX as occurs in the platelet