A-family anti-inflammatory cyclopentenone prostaglandins: A novel class of non-statin inhibitors of HMG-CoA reductase.

Disruption of the intracellular lipid balance leading to cholesterol accumulation is one of the features of cells that participate in the development of atherosclerotic lesions. Evidence form our laboratory indicates that anti-inflammatory cyclopentenone prostaglandins (cyPGs) of A- and J-family deviate lipid metabolism from the synthesis of cholesterol and cholesteryl esters to the synthesis of phospholipids in foam-cell macrophages. cyPGs possessing an α,ß-unsaturated cyclopentane ring are highly electrophilic substances able to promptly react with reactive cysteines of intracellular molecules through Michael addition. On the other hand, HMG-CoA reductase (HMGCR), the enzyme responsible for the rate-limiting step in cholesterol biosynthesis, presents critically reactive cysteines at the entry of catalytic domain, particularly Cys561, that could be target of cyPG inhibition. In the present study, we showed that cyPGs (but not other non-α,ß-unsaturated PGs) physically interact with HMGCR, in a dithiothreitol- and ß-mercaptoethanol-sensitive way, and block the activity of the catalytic subunit of the enzyme (IC50 for PGA2 = 0.17 µM). PGA2 inhibits HMGCR activity in cultured rat and human macrophages/macrophage-foam cells and leads to enhanced expression of HMGCR protein, as observed with statins. In cell culture models, PGA2 effectively inhibits the reductase at non-toxic doses (e.g., 1 µM) that block cell proliferation thus suggesting that part of the well-known antiproliferative effect of PGA2 may be due to its ability of blocking HMGCR activity, as cells cannot proliferate without a robust cholesterogenesis. Therefore, besides the powerfully anti-inflammatory and antiproliferative effects, the anticholesterogenic effects of PGA2 should be exploited in atherosclerosis therapeutics.

Effects of n-3 fatty acids and exercise on oxidative stress parameters in type 2 diabetic: a randomized clinical trial.

BACKGROUND: The relationship between diabetes and oxidative stress has been previously reported. Exercise represents a useful non-pharmacological strategy for the treatment in type 2 diabetic (T2DM) patients, but high intensity exercise can induce a transient inflammatory state and increase oxidative stress. Nutritional strategies that may contribute to the reduction of oxidative stress induced by acute exercise are necessary. The aim of this study was to examine if n-3 PUFA supplementation intervention can attenuate the inflammatory response and oxidative stress associated with high intensity exercise in this population. As a primary outcome, lipoperoxidation measurements (TBARS and F2-isoprostanes) were selected. METHODS: Thirty T2DM patients, without chronic complications, were randomly allocated into two groups: placebo (gelatin capsules) or n-3 PUFA (capsules containing 180 mg of eicosapentaenoic acid and 120 mg of docosahexaenoic acid). Blood samples were collected fasting before and after 8 weeks supplementation. In the beginning and at the end of protocol, an acute exercise was performed (treadmill), and new blood samples were collected before and immediately after the exercise for measurements of oxidative stress and high-sensitivity C-reactive protein (hs-CRP). RESULTS: After the supplementation period, a decrease in triglycerides levels was observed only in n-3 PUFA supplementation group (mean difference and 95% CI of 0.002 (0.000-0.004), p = 0.005). Supplementation also significantly reduced TRAP levels after exercise (mean difference and 95% CI to 9641 (- 20,068-39,351) for - 33,884 (- 56,976 - -10,793), p = 0.004, Cohen's d effect size = 1.12), but no significant difference was observed in n-3 PUFA supplementation group in lipoperoxidation parameters as TBARS (mean difference and 95% CI to - 3.8 (- 10-2.4) for - 2.9 (- 1.6-7.4) or F2-isoprostanes (mean difference and 95% CI -0.05 (- 0.19-0.10) for - 0.02 (- 0.19-0.16), p > 0.05 for both. CONCLUSION: PUFA n-3 supplementation reduced triglycerides as well as TRAP levels after exercise, without a significant effect on inflammatory and oxidative stress markers.This study is registered at ClinicalTrials.gov with the registration number of NCT03182712.

Evaluation of Ricinus communis L. for the Phytoremediation of Polluted Soil with Organochlorine Pesticides.

Phytoremediation is an attractive alternative to conventional treatments of soil due to advantages such as low cost, large application areas, and the possibility of in situ treatment. This study presents the assessment of phytoremediation processes conducted under controlled experimental conditions to evaluate the ability of Ricinus communis L., tropical plant species, to promote the degradation of 15 persistent organic pollutants (POPs), in a 66-day period. The contaminants tested were hexachlorocyclohexane (HCH), DDT, heptachlor, aldrin, and others. Measurements made in rhizosphere soil indicate that the roots of the studied species reduce the concentration of pesticides. Results obtained during this study indicated that the higher the hydrophobicity of the organic compound and its molecular interaction with soil or root matrix the greater its tendency to concentrate in root tissues and the research showed the following trend: HCHs < diclofop-methyl < chlorpyrifos < methoxychlor < heptachlor epoxide < endrin < o,p'-DDE < heptachlor < dieldrin < aldrin < o,p'-DDT < p,p'-DDT by increasing order of log K ow values. The experimental results confirm the importance of vegetation in removing pollutants, obtaining remediation from 25% to 70%, and demonstrated that Ricinus communis L. can be used for the phytoremediation of such compounds.

Role of alpha- and beta-adrenoreceptors in rat monocyte/macrophage function at rest and acute exercise

Previous studies from our laboratory have demonstrated that a single bout of moderate exercise stimulates macrophage function, increasing phagocytic capacity, and production of hydrogen peroxide and nitric oxide (NO˙) through nuclear factor kappa B activation. In this work, we investigated the role of α- and β-adrenoreceptors on the function of monocyte/macrophages during rest and exercise. Adult male Wistar rats were i.p. administered (100 μL/100 g) with specific adrenergic antagonists before an acute moderate exercise bout: prazosin (α1-specific antagonist 2 mg/kg), propranolol (unspecific β1/β2 antagonist 10 mg/kg), double blockade (α1 and β1/β2), or phosphate-buffered saline (control). Acute exercise consisted in a single swimming session of moderate intensity (5 % body weight overload on the chest) for 60 min. Control groups (rest) received the same antagonists and were killed 60 min after drug administration. Exercise increased phagocytic capacity (1.7-fold, p < 0.05), NO˙ production (5.24 fold, p < 0.001), and inducible nitric oxide synthase (NOS2) expression (by 58.1 %), thus suggesting macrophage activation. The β-adrenoreceptor blockade did not change this behavior. In resting animals, α1 antagonist, as well as the double (α1/β) blockade, however, further increased phagocytic capacity (by up to 261 %, p < 0.001), NO˙ production (by up to 328 %, p < 0.001), and the expressions of NOS2 (by 182 %, p < 0.001) and HSP70 (by 42.5 %, p < 0.01) suggesting a tonic inhibitory effect of α1 stimulation on macrophage activation. In exercised animals, α1-blockade showed similar enhancing effect on phagocytic indices and expressions of NOS and HSP70, particularly in double-blocked groups, although NO˙ production was found to be reduced in exercised animals submitted to both α- and β-blockade. Redox (glutathione) status and lipoperoxidation were evaluated in all test groups and approximately paralleled macrophage NO˙ production. We suggest the prevalence of a peripheral α1-adrenoreceptor inhibitory tonus that limits macrophage responsiveness but operates differently after physical exercise

Role of alpha- and beta-adrenoreceptors in rat monocyte/macrophage function at rest and acute exercise.

Previous studies from our laboratory have demonstrated that a single bout of moderate exercise stimulates macrophage function, increasing phagocytic capacity, and production of hydrogen peroxide and nitric oxide (NO˙) through nuclear factor kappa B activation. In this work, we investigated the role of α- and ß-adrenoreceptors on the function of monocyte/macrophages during rest and exercise. Adult male Wistar rats were i.p. administered (100 µL/100 g) with specific adrenergic antagonists before an acute moderate exercise bout: prazosin (α1-specific antagonist 2 mg/kg), propranolol (unspecific ß1/ß2 antagonist 10 mg/kg), double blockade (α1 and ß1/ß2), or phosphate-buffered saline (control). Acute exercise consisted in a single swimming session of moderate intensity (5% body weight overload on the chest) for 60 min. Control groups (rest) received the same antagonists and were killed 60 min after drug administration. Exercise increased phagocytic capacity (1.7-fold, p < 0.05), NO˙ production (5.24 fold, p < 0.001), and inducible nitric oxide synthase (NOS2) expression (by 58.1%), thus suggesting macrophage activation. The ß-adrenoreceptor blockade did not change this behavior. In resting animals, α1 antagonist, as well as the double (α1/ß) blockade, however, further increased phagocytic capacity (by up to 261%, p < 0.001), NO˙ production (by up to 328%, p < 0.001), and the expressions of NOS2 (by 182%, p < 0.001) and HSP70 (by 42.5%, p < 0.01) suggesting a tonic inhibitory effect of α1 stimulation on macrophage activation. In exercised animals, α1-blockade showed similar enhancing effect on phagocytic indices and expressions of NOS and HSP70, particularly in double-blocked groups, although NO˙ production was found to be reduced in exercised animals submitted to both α- and ß-blockade. Redox (glutathione) status and lipoperoxidation were evaluated in all test groups and approximately paralleled macrophage NO˙ production. We suggest the prevalence of a peripheral α1-adrenoreceptor inhibitory tonus that limits macrophage responsiveness but operates differently after physical exercise.

Oxidation of melatonin by taurine chloramine.

Melatonin is widely known for its antioxidant, immunomodulatory, and anti-inflammatory effects. Hypochlorous acid (HOCl) is one example of an endogenous oxidant that is promptly neutralized by melatonin. Melatonin also inhibits myeloperoxidase, the enzyme that catalyzes the oxidation of chloride to HOCl. Taurine is the most abundant free amino acid in leukocytes. In activated neutrophils, taurine is converted to taurine chloramine (Tau-NHCl) through a reaction with HOCl. In addition, the related compound taurine bromamine (Tau-NHBr) can be released by neutrophils and eosinophils. The aim of this study was to investigate the reactivity of Tau-NHCl and Tau-NHBr with melatonin. We found that melatonin can react with either Tau-NHCl or Tau-NHBr, leading to the production of 2-hydroxymelatonin and N(1)-acetyl-N(2)-formyl-5-methoxykynuramine (AFMK). The reaction was pH-dependent, and it occurs more rapidly at a slightly acidic pH. Tau-NHBr was significantly more reactive than Tau-NHCl. Using Tau-NHBr as the oxidizing agent, 1 mm melatonin was oxidized in less than 1 min. The pH dependence of the reaction with Tau-NHCl and the increased reactivity of Tau-NHBr can be explained by a mechanism based on the initial attack of chloronium (Cl(+)) or bromonium (Br(+)) ions on melatonin. We also found that the addition of iodide to the reaction medium increased the yield of AFMK. These findings could contribute to the establishment of new functions for melatonin in inflammatory and parasitic diseases, where the role of this indoleamine has been extensively investigated.

The co-catalytic effect of chlorpromazine on peroxidase-mediated oxidation of melatonin: enhanced production of N1-acetyl-N2-formyl-5-methoxykynuramine.

Accumulating evidence points to relationships between increased production of reactive oxygen or decreased antioxidant protection in schizophrenic patients. Chlorpromazine (CPZ), which remains a benchmark treatment for people with schizophrenia, has been described as a pro-oxidant compound. Because the antioxidant compound melatonin exerts protective effects against CPZ-induced liver disease in rats, in this investigation, our main objective was to study the effect of CPZ as a co-catalyst of peroxidase-mediated oxidation of melatonin. We found that melatonin was an excellent reductor agent of preformed CPZ cation radical (CPZ(*+)). The addition of CPZ during the horseradish peroxidase (HRP)-catalyzed oxidation of melatonin provoked a significant increase in the rate of oxidation and production of N(1)-acetyl-N(2)-formyl-5-methoxykynuramine (AFMK). Similar results were obtained using myeloperoxidase. The effect of CPZ on melatonin oxidation was rather higher at alkaline pH. At pH 9.0, the efficiency of oxidation of melatonin was 15 times higher and the production of AFMK was 30 times higher as compared with the assays in the absence of CPZ. We suggest that CPZ is able to exacerbate the rate of oxidation of melatonin by an electron transfer mechanism where CPZ(*+), generated during the peroxidase-catalyzed oxidation, is able to efficiently oxidize melatonin.

Flow-injection spectrophotometric determination of novalgin in pharmaceuticals using micellar medium.

A sensitive flow-injection (FI) procedure with spectrophotometric detection in a micellar medium is proposed for the determination of novalgin. The method is based on the instantaneous formation of a red-orange product (lambda(max) = 510 nm) after the reaction between novalgin and p-dimethylaminocinnamaldehyde (p-DAC) in a dilute acid medium. The sensitivity of this reaction was increased by a factor of 5.6 in the presence of sodium dodecyl sulfate (SDS). Experimental design methodologies were used to optimize the chemical and FI variables. The calibration curve was linear in the range of 1.45 x 10(-6) to 2.90 x 10(-5) mol L(-1) with an excellent correlation coefficient (r = 0.9999). The detection limit was 1.31 x 10(-7) mol L(-1) (n = 20, RSD = 2.0%). No interferences were observed from the common excipients. The results obtained by the proposed method were favorably compared with those given by the iodometric reference method at 95% confidence level.

The effect of pH on horseradish peroxidase-catalyzed oxidation of melatonin: production of N1-acetyl-N2-5-methoxykynuramine versus radical-mediated degradation.

There is a growing body of evidence that melatonin and its oxidation product, N(1)-acetyl-N(2)-formyl-5-methoxykynuramine (AFMK), have anti-inflammatory properties. From a nutritional point of view, the discovery of melatonin in plant tissues emphasizes the importance of its relationship with plant peroxidases. Here we found that the pH of the reaction mixture has a profound influence in the reaction rate and products distribution when melatonin is oxidized by the plant enzyme horseradish peroxidase. At pH 5.5, 1 mm of melatonin was almost completely oxidized within 2 min, whereas only about 3% was consumed at pH 7.4. However, the relative yield of AFMK was higher in physiological pH. Radical-mediated oxidation products, including 2-hydroxymelatonin, a dimer of 2-hydroxymelatonin and O-demethylated dimer of melatonin account for the fast consumption of melatonin at pH 5.5. The higher production of AFMK at pH 7.4 was explained by the involvement of compound III of peroxidases as evidenced by spectral studies. On the other hand, the fast oxidative degradation at pH 5.5 was explained by the classic peroxidase cycle.