Milan Číž

Comparative content of some bioactive compounds in apples, peaches and pears and their influence on lipids and antioxidant capacity in rats

The aim of this study was to compare some bioactive compounds in apples, peaches and pears and their influence on lipids and antioxidant capacity in rats. The content of total polyphenols (g/100g) was 0.23 +/- 0.03; 0.22 +/- 0.03 and 0.68 +/- 0.1 in peeled fruits and 0.48 +/- 0.04, 0.47 +/- 0.04 and 1.2 +/- 0.12 in peels of peaches, pears and apples, respectively. Caffeic, p-coumaric and ferulic acids and the total radical-trapping antioxidative potential (TRAP) values in peeled apples and their peels were significantly higher than in peaches and pears, respectively. Contrarary, no significant differences in the content of dietary fiber among the studied fruits were found. The content of all studied indices in peels was significantly higher than peeled fruits (p < 0.05 ). A good correlation between the total polyphenols and the TRAP values was found in all fruits. Diets supplemented with apples and to a less extent with peaches and pears have improved lipid metabolism and increased the plasma antioxidant potential especially in rats fed with added cholesterol. The highest content of biologically active compounds and the best results in the experiment on rats makes apple preferable for dietary prevention of atherosclerosis and other diseases.

Comparison of the contents of the main biochemical compounds and the antioxidant activity of some Spanish olive oils as determined by four different radical scavenging tests.

The aim of this study was to compare the contents of the main biochemical compounds and the antioxidant capacity of five Spanish olive oils by four different antioxidant tests and to find out the most valuable oil for disease preventing diets. Fatty acids, sterols and individual antioxidant compounds in Arbequina, Hojiblanca, Extra Virgin, Picual and Lampante Spanish olive oils were determined. Antioxidant activities were done as well using different radical scavenging activities: total radical-trapping antioxidative potential by ABAP (TRAP-ABAP), radical scavenging activity by DPPH (RSA-DPPH), antioxidant assay by beta-carotene-linoleate model system (AA-beta-carotene) and total antioxidant status by ABTS (TAA-ABTS). The highest content of all studied antioxidant compounds (353; 329; 4.6 and 2.7 mg/kg for tocopherols, tocotrienols, polyphenols and o-diphenols, respectively) was found in Extra Virgin oil. Also the highest antioxidant capacity was observed in Extra Virgin oil (668 nM/ml; 29.4%; 40.4% and 2.64 mM TE/kg for TRAP-ABAP, RSA-DPPH, AA- beta-carotene and TAA-ABTS, respectively). The correlation between total phenols and antioxidant capacities measured by four methods was very high, but the highest for the beta-carotene (R = 0.9958). In conclusion, the best method for determination of the antioxidant capacity of olive oils is the beta-carotene test. Extra Virgin olive oil has high organoleptic properties and the highest antioxidant activity. The above-mentioned makes this oil a preferable choice for diseases preventing diets.

Reactive oxygen metabolite production is inhibited by histamine and H1-antagonist dithiaden in human PMN leukocytes.

The study evaluated the distinction between extracellular and intracellular production of reactive oxygen metabolites (ROM) in isolated polymorphonuclear leukocytes (PMNL) stimulated with opsonised zymosan (OZ) and investigated its modulation by the endogenous mediator histamine (0.1-100 w mol/l) and by the H 1 -antagonist dithiaden (1-100 w mol/l). For this observation, a modified luminol and an isoluminol amplified chemiluminescence (CL) technique were used. Our results showed that PMNL activated with OZ responded with a respiratory burst accompanied by both extra- and intracellular generation of ROM. Histamine and dithiaden significantly decreased both the extra- and intracellular component of chemilumiescence stimulated with OZ. While dithiaden decreased both the extra- and intracellular part of CL with the same potency, histamine decreased preferentially the extracellular part of CL. The fact that histamine as well as the H 1 -antagonist dithiaden decreased the respiratory burst indicates that not only histamine receptors but also non-receptor mechanisms could be involved in the reduction of CL. Interaction with enzymes (NADPH-oxidase, myeloperoxidase, phospholipase A 2 ) or interference with PMNL membrane structure may well result in reduction of the chemiluminescence signal.

Seed oils improve lipid metabolism and increase antioxidant potential in rats fed diets containing cholesterol

Abstract The goal of this investigation was to find the most valuable among four often-used seed oils for atherosclerosis preventing diets. Fatty acids, sterols, antioxidant compounds, stability and total radical-trapping antoxidative potential (TRAP) in sunflower, sunflower high oleic, rapeseed and grapeseed oils were determined. The highest stability and the highest TRAP (3.8 Rancimat 120°C, hours and 324 nmol/ml) and the lowest stability and the lowest TRAP (2.4 Rancimat 120°C, hours and 201 nmol/ml) were in rapeseed and sunflower oils, respectively. The effect of these two seed oils on lipid metabolism and antioxidant activity was investigated on 60 (divided in six diet groups of 10) male Wistar rats adapted to cholesterol-free or 1% cholesterol diets. The control group (Control) consumed basal diet (BD) only. To the BD were added 10g/100g rapeseed (Rapeseed group) or sunflower (Sunflower group) oils, 1 g/100 g cholesterol (Chol group) or both (Chol/Rapeseed group) and (Chol/Sunflower group). The experiment lasted 4 weeks. In the Chol/Rapeseed and Chol/Sunflower vs. Chol group, the oil supplemented diets significantly ( P

Modulation of neutrophil oxidative burst via histamine receptors

Histamine has the ability to influence the activity of immune cells including neutrophils and plays a pivotal role in inflammatory processes, which are a complex network of cellular and humoral events. One of the main functions manifested by activated neutrophils is oxidative burst, which is linked to the production of reactive oxygen species; therefore, the effects of histamine receptor agonists and antagonists on the oxidative burst of neutrophils is reviewed. A role for the well‐characterized histamine H1 and H2 receptors in this process is discussed and compared to that of the recently discovered H4 receptor.

Serotonin modulates the oxidative burst of human phagocytes via various mechanisms.

Serotonin, the major secretory product of activated platelets, has been widely reported as regulating various constituents of the immune system and immune functions. This modulation is complex and the data available are rather controversial. The aim of the present study was to clarify the mechanisms of serotonin action on human phagocytes. The effect of serotonin in a concentration range of 10−7 M–10−3 M on various parameters of oxidative burst of phagocytes was studied using various luminol-enhanced chemiluminescence methods. Serotonin inhibited the chemiluminescence response of the cells in a dose dependent manner. The effect of serotonin on the activity of myeloperoxidase was studied in further experiments. In this case, serotonin again exerted a dose dependent inhibition of the myeloperoxidase activity. The hypothesis that the inhibitory activity of serotonin might be also receptor mediated was evaluated using various serotonin receptor agonists and antagonists. None of the agonists studied exerted any direct antioxidative properties. Only (±)-DOI hydrochloride, a selective 5-HTR2 agonist, exerted similar effects on phagocytic cells as serotonin. It can be concluded that serotonin could affect the oxidative burst of phagocytes. Responsibility for its inhibitory effects lies with both the decrease in the generation of reactive oxygen species (due to the inhibition of myeloperoxidase activity) and with direct scavenging of reactive oxygen species. The effect of serotonin on phagocytes is also partially mediated by 5-HTR2 receptor.

Soluble glucomannan isolated from Candida utilis primes blood phagocytes.

It is well documented that the polysaccharide glucomannan (GM), an abundant constituent of the fungal cell wall, in the form of particulate induces strong activation of phagocytes, however, the effects of soluble GM are not known. Activation of phagocyte anti-microbial mechanisms is a crucial part of the innate host defense against invading pathogens. However, under uncontrolled inflammatory conditions they contribute to damage of surrounding tissues. Thus, to prevent these deleterious effects, the activation of phagocytes is a tightly regulated process. Therefore, in this study we analyzed the effect of soluble GM on some neutrophil functions such as reactive oxygen species production, degranulation, and receptor mobilization at the plasma membrane. Soluble GM at the tested concentrations did not stimulate oxidative burst of phagocytes directly but significantly potentiated oxidative burst in response to opsonized zymosan particles. GM induced significant phosphorylation of p47phox subunit of NADPH oxidase on Ser345. This priming effect of GM was accompanied by time and concentration dependent degranulation characterized by increased surface expression of receptors stored in neutrophil granules (CD10, CD11b, CD14, CD35, and CD66b). Degranulation was further confirmed by increase of elastase activity in media. Thus, it could be suggested that soluble GM induces priming of phagocytes connected with their degranulation, the increase of surface receptor expression, and potentiation of oxidative burst response to opsonized particles through the activation of NADPH oxidase.

Effect of H1-antagonist Dithiaden on human PMN-leukocyte aggregation and chemiluminescence is stimulus-dependent.

Abstract.Objective and design: Contradictory data published on histamine-PMN leukocyte interactions stimulated us to study to the role of histamine and H1-antagonist Dithiaden® in generation of reactive oxygen species (ROS) and aggregation of human neutrophils.¶Methods and materials: Whole blood or isolated PMN-leukocytes were exposed in a dose-dependent way to histamine or H1-antagonist Dithiaden® and subsequently stimulated. Whole blood was stimulated with opsonised zymosan (OZ). Isolated cells were stimulated with membrane stimuli (OZ, N-formyl-methionyl-leucyl-phenylalanine – fMLP), or membrane bypassing stimuli (Ca2+-ionophore A23187, phorbol-myristate-acetate – PMA). The luminol-enhanced chemiluminescence (CL) was measured separately (whole blood) in a luminometer or simultaneously with neutrophil aggregation in a whole blood lumiaggregometer.¶Results: Depending on the concentration used, Dithiaden® was 1.5- to 25.0-times more effective in inhibiting activated CL of whole blood than histamine. In isolated neutrophils both histamine and Dithiaden® inhibited OZ- and A23187-stimulated CL dose-dependently, with potentiation observed after stimulation with PMA and fMLP. Histamine did not alter aggregation with any of the stimuli tested. Dithiaden® inhibited A23187-, OZ- and PMA-stimulated PMN-leukocytes but potentiated fMLP-induced aggregation of isolated neutrophils. Simultaneous application of Dithiaden® and histamine abolished the effect of Dithiaden® on fMLP-stimulated CL.¶Conclusions: Dithiaden®, depending on the stimuli applied, inhibited human neutrophils, both isolated or in whole blood, more markedly than histamine. The inhibition of aggregation and CL was dose- and stimulus-dependent. Histamine administered simultaneously abolished the effect of Dithiaden® on fMLP-stimulated PMN-leukocytes. It seems likely that the interaction of Dithiaden® with neutrophils operated both at an extra- and intracellular level.

Serotonin and its 5-HT2 receptor agonist DOI hydrochloride inhibit the oxidative burst in total leukocytes but not in isolated neutrophils

AIMS Serotonin (5-HT) is capable of reducing the oxidative burst of professional phagocytes. In this study, we investigated whether 5-HT mediates this modulation via 5-HT receptors (5-HTR) or whether this is due instead to 5-HT antioxidative properties. MAIN METHODS The leukocytes or polymorphonuclear leukocytes (PMNL) were isolated from human blood, and their ability to produce reactive oxygen species (ROS) after 5-HT or its agonist treatment was tested by luminol-enhanced chemiluminescence (CL) analysis. KEY FINDINGS It was found that 5-HTR(2) agonist DOI hydrochloride does not have any antioxidative properties, despite its ability to inhibit the CL response of activated human total leukocytes. On the other hand, DOI hydrochloride was unable to inhibit the CL response of activated human PMNL. It seems that the reduction of the oxidative burst of professional phagocytes was evoked by the activation of 5-HTR not on the neutrophil surface but on the surface of different leukocytes, which produced anti-inflammatory cytokines with NADPH oxidase activity modulating properties. SIGNIFICANCE Platelets and activated PMNL are in tight contact at sites of inflammation. 5-HT released from platelets might have a protective function against PMNL-derived oxidative stress and oxidative damages.

The effects of H1-antihistamines on the nitric oxide production by RAW 264.7 cells with respect to their lipophilicity

H1-antihistamines are known to be important modulators of inflammatory response. However, the information about the influence of these drugs on reactive nitrogen species generation is still controversial. The main aim of the present study was to investigate the effects of selected H1-antihistamines on nitric oxide production by lipopolysaccharide-stimulated murine macrophages RAW 264.7, measured as changes in inducible nitric oxide synthase (iNOS) protein expression in cell lysates by Western blotting and nitrite formation in cell supernatants using the Griess reaction. In pharmacological non-toxic concentrations, H1-antihistamines significantly inhibited nitrite accumulation that was not caused by the scavenging ability of drugs against nitric oxide, measured amperometrically. The degree of inhibition of nitrite accumulation positively correlated with the degree of tested lipophilicity, measured by reversed-phase thin layer chromatography. Furthermore, H1-antihistamines differentially modulated the iNOS protein expression. In conclusion, as was shown in this study, the modulation of nitric oxide production could be caused by the downregulation of iNOS protein expression and/or the iNOS protein activity.